Adding splitting screen and buffer switching

.gitea/workflows/build.yml

@@ -0,0 +1,35 @@
+name: Build project
+
+on:
+  push:
+    branches: ["main"]
+
+jobs:
+  build:
+    runs-on: giorgio-runner
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          tokens: ${{ secrets.GITEA_TOKEN }}
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y meson ninja-build gcc
+
+      - name: Configure Meson
+        run: meson setup build
+
+      - name: Build project
+        run: meson compile -C build
+
+      - name: Run tests
+        run: ctest --test-dir build || true
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: beluga
+          path: build/beluga

.gitignore

@@ -1,3 +1,3 @@
-tmp/*
-bin/*
+build/*
 doc/*
+beluga.wiki/*

Makefile

@@ -1,32 +0,0 @@
-##
-# TEST
-#
-# @file
-# @version 0.1
-
-BELUGA_OUTPUT=bin
-
-BUILD_FLAGS=-Wall -Wextra -pedantic
-
-build: main.c src/*
-	if [ ! -d $(BELUGA_OUTPUT) ]; then mkdir $(BELUGA_OUTPUT); fi
-	$(CC) main.c -o $(BELUGA_OUTPUT)/beluga src/* $(BUILD_FLAGS)
-
-DEBUG_FLAGS=-Wall -Wextra -pedantic -Werror -fsanitize=address -g
-
-debug:  main.c src/*
-	if [ ! -d $(BELUGA_OUTPUT) ]; then mkdir $(BELUGA_OUTPUT); fi
-	$(CC) main.c -o $(BELUGA_OUTPUT)/beluga src/* $(DEBUG_FLAGS)
-
-doc:
-	if [ ! -d doc/ ]; then mkdir doc; fi
-	doxygen
-
-clean:
-	rm -r $(BELUGA_OUTPUT)
-	rm -rf doc/
-	rm -rf tmp/
-
-all: build doc
-
-# end

README.md

@@ -1,26 +1,32 @@
 # Beluga
 
-Beluga is a project of CLI text editor that will fit perfectly with your azerty keyboard.
+Beluga is a project of CLI text editor that uses lisp as configuration language.
 
 ## Requirements
 
-You will only need **make** or **gcc** to compile the editor.
+You will only need **meson** and a **C compiler** to compile the editor.
 
 ## Installation
+### From source
+Here is the installation line for development version:
 
-Here is the installation line :
+```git clone https://git.giorgio-nas.fr/arthur/beluga.git && cd beluga && meson setup build && meson compile -C build```
 
-```git clone --branch V1.0 --single-branch https://github.com/le-cocotier/beluga.git ~/.beluga && cd ~/.beluga && make build```
+The executable file will be `build/beluga`. Feel free to add it to your path.
 
-The executable file will be in `bin/beluga`. Feel free to add it to your path.
+### From installation script ( prefered )
 
-You can either run `make all` if you're interested by the doxygen documentation.
+Just clone the repo and execute the script `install.sh`. It will automatically add beluga to your path.
 
 ## Getting start
 
 To open an existing file just type :
-```beluga path_to_my_file```
+```./build/beluga path_to_my_file```
 
-The only keybinds that you will need will be :
- - Ctrl-Q : leave the editor
- - Ctrl-S : Save a file
+Here is some few command that you will need :
+
+| keybind       | command          |
+|---------------|------------------|
+| Ctrl-x Ctrl-c | leave the editor |
+| Ctrl-x Ctrl-s | Save a file      |
+| Ctrl-x f      | open file        |

assets/beluga.txt

@@ -0,0 +1,43 @@
+                      **#%#*****###%**
+                *##+--------------------=##*  
+             #*=----------------------------=*#*                                 
+          #*------------------------------------*#                               
+        %+----------------------------------------=#*                            
+       #+---------------------------------------------##                            
+     *#-------------------------------------------------=##                         
+    *#----------------------------------------------------:-##
+    #----------------------------------------------------------##                   
+   #=--------------------------------------------------------------##                
+  +--------------------------+@#-%*-----------------------------------#*         
+  +--------------------------%@@@@#-------------------------------------**                              BELUGA - VERSION 2.3
+  *-=-------------------------#@@*---------------------------------------=%
+  %*#==--------------------------------------------------------------------+#                           ----- KEY-BINDS -----
+  *%%=-=--------------------------------------------------------------------=#                          CTRL-x CTRL-c  leave
+  %=--------------------------------------------------------------------------#*                        CTRL-x CTRL-s   save
+ %-----------------------------------------------------------------------------**                       CTRL-x f   open-file
+*+--=---===----=---------------=*-----------------------------------------------** 
+ #--=##      *#%#*+==----==+**+----------------------=  ***=---------------------% 
+ *%**=-----------====    ==---------------------------------=+#+-----------------=#                                 
+   *%=----------------------------------------------------------=#*---------------#                                 
+     ##=----------------------------------=------------------------+%=------------+#                                
+       #%+---------------------------------=*------------------------+%------------#                                
+         *#%*=-------------=-----------------#-------------------------#+----------#                                
+             **#%#*******+=======-------------#=------------------------#----------#                                
+                #===#*=======------------------#*----=-----------=--=##*-----------#                                
+                 -====##=------------------------*%+------------=*#+=====----------#                                
+                 --=====+#*=----------------------=-=+*#####***+=======-----------=*                                
+                %------=====*%*=-------------------------========-----------------+*                                
+                 *-=--------====%%###+=--------------------------=-----------------#                                
+                  #-----------=%        +*##%%%%%%@@%%%%####*==---------------------**                              
+                    %=-------#*                                  #%*=-----------------+#                              
+                     *%+--=##                                       ##=-----------------=#*                           
+                        **                                       #+----=-------------------#*                       
+                                                               %+----------------------------#*                     
+                                                             *%-------------==----------------+#                    
+                                                            ##--------------==------------------#                     
+                                                           *#--------------===%-----------------=%                  
+                                                          ##---------------=-##*-----------------+#                 
+                                                        *#---------------==#+=#%-----------------%                 
+                                                       *%---------------+#      %*---------------#*                  
+                                                      *#------------=+#*          #%*=-----------#*                  
+                                                       #****##******                 *#%%##+=----%                 

config/init.lisp

@@ -0,0 +1,89 @@
+;; MACROS
+
+(define TAB-LENGTH 4)
+(define QUIT-TIMES 1)
+(define THEME "dark")
+
+;; PACKAGES
+
+;; First git clone it
+;; (add-package "smart_delimiters")
+
+;; FUNCTIONS
+
+(define editor-delete-next-char (lambda () (
+                                            (move-cursor "right")
+                                            (editor-delete-previous-char)
+                                            )
+                                  )
+  )
+
+
+(define (char-between ch lo hi)
+  (if (char>=? ch lo)
+      (char<=? ch hi)
+      #f))
+
+(define (alphanumericp ch)
+  (if ch
+      (if (char-between ch #\a #\z)
+          #t
+          (if (char-between ch #\A #\Z)
+              #t
+              (if (char-between ch #\0 #\9)
+                  #t
+                  #f)))
+      #f))
+
+
+(define (word-char-p ch)
+  (if (alphanumericp ch)
+      #t
+      #f))
+
+(define editor-move-to-end-of-word (lambda () (
+  (if (word-char-p (editor-read-char))
+	((move-cursor "right")
+	(editor-move-to-end-of-word))
+    ))
+                                     ))
+
+(define enter-and-tab 
+  (lambda () 
+    (editor-insert-new-line)
+    (let ((is-in (move-cursor "up")))
+      (do ((ch (editor-read-char) (editor-read-char)))
+          ((and (not (char=? ch #\space)) is-in) #f)
+        (move-cursor "down")
+        (editor-insert-char " ")
+        (set! is-in (move-cursor "up")))
+      (move-cursor "down"))))
+
+(add-prefix "user")
+
+
+
+(map-key "CTRL-x" '(editor-set-prefix "user") "no-prefix")
+(map-key "CTRL-g" '(editor-set-prefix "no-prefix") "user")
+(map-key "CTRL-c" editor-quit "user")
+(map-key "CTRL-s" editor-save "user")
+(map-key "ARROW-UP" '(move-cursor "up") "no-prefix")
+(map-key "ARROW-DOWN" '(move-cursor "down") "no-prefix")
+(map-key "ARROW-RIGHT" '(move-cursor "right") "no-prefix")
+(map-key "ARROW-LEFT" '(move-cursor "left") "no-prefix")
+(map-key "ENTER" enter-and-tab "no-prefix")
+(map-key "CTRL-a" move-cursor-beg-line "no-prefix")
+(map-key "CTRL-e" move-cursor-end-line "no-prefix")
+(map-key "BACKSPACE" editor-delete-previous-char "no-prefix")
+(map-key "DEL" editor-delete-next-char "no-prefix")
+(map-key "PAGE-UP" move-cursor-page-up "no-prefix")
+(map-key "PAGE-DOWN" move-cursor-page-down "no-prefix")
+(map-key "f" editor-open-file "user")
+(map-key "TAB" editor-insert-tab "no-prefix")
+(map-key "CTRL-k" editor-del-row "no-prefix")
+(map-key "CTRL-s" buffer-find "no-prefix")
+(map-key "CTRL-r" editor-move-to-end-of-word "no-prefix")
+(map-key "\"" editor-split-screen-vertical "user")
+(map-key "o" editor-switch-next-pane "user")
+(map-key "*" editor-unify-panes "user")
+

include/buffer.h

@@ -0,0 +1,58 @@
+/**
+ * @file buffer.h
+ * @brief Buffer management for handling multiple open files
+ */
+
+#ifndef BUFFER_H_
+#define BUFFER_H_
+
+#include "data.h"
+
+/**
+ * @brief Creates a new buffer for a file
+ * @param filename Path to the file
+ * @return Buffer ID on success, -1 on failure
+ */
+int bufferCreate(const char *filename);
+
+/**
+ * @brief Switches to a specific buffer by ID
+ * @param buffer_id The buffer ID to switch to
+ * @return 0 on success, -1 on failure
+ */
+int bufferSwitch(int buffer_id);
+
+struct buffer_t *bufferFindById(int buffer_id);
+
+/**
+ * @brief Closes a buffer by ID
+ * @param buffer_id The buffer ID to close
+ * @return 0 on success, -1 on failure
+ */
+int bufferClose(int buffer_id);
+
+/**
+ * @brief Gets the current active buffer
+ * @return Pointer to current buffer_t, NULL if none
+ */
+struct buffer_t *bufferGetCurrent(void);
+
+/**
+ * @brief Lists all open buffers
+ * @return Number of open buffers
+ */
+int bufferListAll(void);
+
+/**
+ * @brief Saves current buffer to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSave(void);
+
+/**
+ * @brief Saves all buffers to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSaveAll(void);
+
+#endif

include/builtins.h

@@ -0,0 +1,56 @@
+#ifndef BUILTINS_H_
+#define BUILTINS_H_
+
+#include "lisp.h"
+
+// Mouvement
+
+Lisp moveCursor(Lisp args, LispError *e, LispContext ctx);
+Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx);
+Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx);
+Lisp editorMoveCursorPageUp(Lisp args, LispError* e, LispContext ctx);
+Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx);
+
+// Text editing
+
+Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx);
+Lisp l_editorInserTab(Lisp args, LispError *e, LispContext ctx);
+Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx);
+Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx);
+Lisp editorDelRow_L(Lisp args, LispError *e, LispContext ctx);
+Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx);
+
+// Editor
+
+Lisp editorQuit(Lisp args, LispError *e, LispContext ctx);
+Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx);
+Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx);
+Lisp editorPrefix(Lisp args, LispError *e, LispContext ctx);
+Lisp mapKey(Lisp args, LispError *e, LispContext ctx);
+void registerBuiltin(char * key_sequence, LispCFunc f);
+Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx);
+Lisp addPackage(Lisp args, LispError *e, LispContext ctx);
+
+
+// Buffer
+
+Lisp editorSwitchNextBuffer(Lisp args, LispError *e, LispContext ctx);
+Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx);
+
+
+// Pane
+
+Lisp l_editorSplitScreenVertical(Lisp args, LispError *e, LispContext ctx);
+Lisp editorSwitchNextPane(Lisp args, LispError *e, LispContext ctx);
+Lisp editorUnifiedPanes(Lisp args, LispError *e, LispContext ctx);
+
+
+
+
+
+
+// Other
+
+void free_structs(void);
+
+#endif

include/color.h

@@ -0,0 +1,123 @@
+#ifndef COLOR_H_
+#define COLOR_H_
+
+
+// ============================================================================
+// TEXT STYLES / ATTRIBUTES
+// ============================================================================
+#define ANSI_RESET          "\x1b[0m"      // Reset all attributes
+#define ANSI_BOLD           "\x1b[1m"      // Bold text
+#define ANSI_DIM            "\x1b[2m"      // Dim/faint text
+#define ANSI_ITALIC         "\x1b[3m"      // Italic text
+#define ANSI_UNDERLINE      "\x1b[4m"      // Underline text
+#define ANSI_BLINK          "\x1b[5m"      // Blinking text
+#define ANSI_REVERSE        "\x1b[7m"      // Reverse video (invert colors)
+#define ANSI_HIDDEN         "\x1b[8m"      // Hidden/invisible text
+#define ANSI_STRIKETHROUGH  "\x1b[9m"      // Strikethrough text
+
+// ============================================================================
+// FOREGROUND COLORS (30-37 standard, 90-97 bright)
+// ============================================================================
+#define ANSI_BLACK          "\x1b[30m"
+#define ANSI_RED            "\x1b[31m"
+#define ANSI_GREEN          "\x1b[32m"
+#define ANSI_YELLOW         "\x1b[33m"
+#define ANSI_BLUE           "\x1b[34m"
+#define ANSI_MAGENTA        "\x1b[35m"
+#define ANSI_CYAN           "\x1b[36m"
+#define ANSI_WHITE          "\x1b[37m"
+
+// Bright/Light foreground colors (90-97)
+#define ANSI_BRIGHT_BLACK   "\x1b[90m"
+#define ANSI_BRIGHT_RED     "\x1b[91m"
+#define ANSI_BRIGHT_GREEN   "\x1b[92m"
+#define ANSI_BRIGHT_YELLOW  "\x1b[93m"
+#define ANSI_BRIGHT_BLUE    "\x1b[94m"
+#define ANSI_BRIGHT_MAGENTA "\x1b[95m"
+#define ANSI_BRIGHT_CYAN    "\x1b[96m"
+#define ANSI_BRIGHT_WHITE   "\x1b[97m"
+
+// ============================================================================
+// BACKGROUND COLORS (40-47 standard, 100-107 bright)
+// ============================================================================
+#define ANSI_BG_BLACK       "\x1b[40m"
+#define ANSI_BG_RED         "\x1b[41m"
+#define ANSI_BG_GREEN       "\x1b[42m"
+#define ANSI_BG_YELLOW      "\x1b[43m"
+#define ANSI_BG_BLUE        "\x1b[44m"
+#define ANSI_BG_MAGENTA     "\x1b[45m"
+#define ANSI_BG_CYAN        "\x1b[46m"
+#define ANSI_BG_WHITE       "\x1b[47m"
+
+// Bright/Light background colors (100-107)
+#define ANSI_BG_BRIGHT_BLACK   "\x1b[100m"
+#define ANSI_BG_BRIGHT_RED     "\x1b[101m"
+#define ANSI_BG_BRIGHT_GREEN   "\x1b[102m"
+#define ANSI_BG_BRIGHT_YELLOW  "\x1b[103m"
+#define ANSI_BG_BRIGHT_BLUE    "\x1b[104m"
+#define ANSI_BG_BRIGHT_MAGENTA "\x1b[105m"
+#define ANSI_BG_BRIGHT_CYAN    "\x1b[106m"
+#define ANSI_BG_BRIGHT_WHITE   "\x1b[107m"
+
+// ============================================================================
+// 256-COLOR MODE (for more colors)
+// ============================================================================
+// Foreground: \x1b[38;5;Nm  where N is 0-255
+// Background: \x1b[48;5;Nm  where N is 0-255
+// Example macros:
+#define ANSI_FG_256(N)      "\x1b[38;5;" #N "m"
+#define ANSI_BG_256(N)      "\x1b[48;5;" #N "m"
+
+// ============================================================================
+// TRUE COLOR / 24-BIT COLOR (RGB)
+// ============================================================================
+// Foreground: \x1b[38;2;R;G;Bm
+// Background: \x1b[48;2;R;G;Bm
+// Example macros:
+#define ANSI_FG_RGB(R,G,B)  "\x1b[38;2;" #R ";" #G ";" #B "m"
+#define ANSI_BG_RGB(R,G,B)  "\x1b[48;2;" #R ";" #G ";" #B "m"
+
+// ============================================================================
+// CURSOR MOVEMENT
+// ============================================================================
+#define ANSI_CURSOR_UP(N)       "\x1b[" #N "A"    // Move up N lines
+#define ANSI_CURSOR_DOWN(N)     "\x1b[" #N "B"    // Move down N lines
+#define ANSI_CURSOR_RIGHT(N)    "\x1b[" #N "C"    // Move right N columns
+#define ANSI_CURSOR_LEFT(N)     "\x1b[" #N "D"    // Move left N columns
+#define ANSI_CURSOR_HOME        "\x1b[H"          // Move to home (0,0)
+#define ANSI_CURSOR_HIDE        "\x1b[?25l"       // Hide cursor
+#define ANSI_CURSOR_SHOW        "\x1b[?25h"       // Show cursor
+
+// ============================================================================
+// SCREEN CONTROL
+// ============================================================================
+#define ANSI_CLEAR_SCREEN   "\x1b[2J"      // Clear entire screen
+#define ANSI_CLEAR_LINE     "\x1b[K"       // Clear from cursor to end of line
+#define ANSI_CLEAR_UP       "\x1b[1J"      // Clear from cursor to start
+#define ANSI_CLEAR_DOWN     "\x1b[0J"      // Clear from cursor to end
+
+// ============================================================================
+// EXAMPLE USAGE
+// ============================================================================
+/*
+#include <stdio.h>
+
+int main(void) {
+    // Simple color example
+    printf("%sHello in Red%s\n", ANSI_RED, ANSI_RESET);
+    
+    // Bold and colored
+    printf("%s%sBold Green%s\n", ANSI_BOLD, ANSI_GREEN, ANSI_RESET);
+    
+    // Background color
+    printf("%s%sYellow on Blue%s\n", ANSI_YELLOW, ANSI_BG_BLUE, ANSI_RESET);
+    
+    // Combine multiple styles
+    printf("%s%s%sUnderlined Bold Cyan%s\n", 
+           ANSI_UNDERLINE, ANSI_BOLD, ANSI_CYAN, ANSI_RESET);
+    
+    return 0;
+}
+*/
+
+#endif

include/data.h

@@ -1,40 +1,149 @@
 #ifndef DATA_H_
 #define DATA_H_
 
+#include <stdio.h>
 #include <termios.h>
 #include <time.h>
 
+#include "lisp.h"
+
 /**
  * \struct erow
  * \brief Store one editor row
  * \param
  * */
 
-typedef struct erow {
+typedef struct frow {
   int size;     /**< Size of the line */
   int rsize;    /**< Size of the render line */
   char *chars;  /**< Characters of the line */
   char *render; /**< The actual line we will print */
-} erow;
+} frow;
+
+
+/**
+ * @brief Split modes for screen layout
+ */
+typedef enum {
+    SPLIT_NONE = 0,      // Single buffer fullscreen
+    SPLIT_VERTICAL,      // Left-right split
+    SPLIT_HORIZONTAL     // Top-bottom split
+} SplitMode;
+
+/**
+ * @brief Represents an editor viewport/pane
+ */
+typedef struct {
+    int buffer_id;        // Which buffer this pane displays
+    int start_row;        // Starting row on screen
+    int start_col;        // Starting column on screen
+    int height;           // Height of this pane
+    int width;            // Width of this pane
+    int cursor_x;         // Local cursor x in this pane
+    int cursor_y;         // Local cursor y in this pane
+  int rx, ry; 
+    int row_offset;       // Scroll offset for rows
+    int col_offset;       // Scroll offset for columns
+    int is_active;        // Is this pane currently active
+} EditorPane;
+
+/**
+ * @brief Screen layout manager
+ */
+typedef struct {
+    SplitMode mode;
+    EditorPane *panes;
+    int num_panes;
+    int active_pane;      // Index of active pane
+} ScreenLayout;
+
+
+typedef struct theme {
+  char *BACKGROUND_COLOR;
+  char *COLOR_KEYWORD;
+  char *COLOR_TYPE;
+  char *COLOR_STRING;
+  char *COLOR_COMMENT;
+  char *COLOR_NUMBER;
+  char *COLOR_DEFAULT;
+
+} theme_t;
+
+enum bufferStatus_e {
+  IDLE,
+  READ_ONLY,
+  READ_AND_WRITE,
+};
+
+struct const_t {
+  int TAB_LENGTH;
+  int QUIT_TIMES;
+  char *THEME;
+};
+
+struct prefix_t {
+  char prefix_name[64];
+  int prefix_id;
+};
+
+struct keyBind_t {
+  char *key_sequence;
+  int prefix_id;
+  Lisp command;
+};
+
+enum buffer_type { FILE_BUFF, TERMINAL_BUFF };
+
+struct buffer_t {
+  enum buffer_type type;
+  int buffer_id;
+  int width, height;
+  int x, y; /**< Position in the buffer (cursor) */
+  frow *row;
+  int numrows;
+  char *filename;
+  enum bufferStatus_e state;
+  int dirty;             /**< Has this buffer been modified since last save */
+  int row_offset;        /**< Scroll offset for rows in this buffer */
+  int col_offset;        /**< Scroll offset for columns in this buffer */
+};
 
 /**
  * \struct editorConfig
  * \brief Containing our editor state.
  */
 struct editorConfig {
-  int cursor_x, cursor_y; /**< Cursor position */
-  int rx;                 /**< Position in the render*/
-  int row_offset;         /**< Position scroll of lines */
-  int col_offset;         /**< Position scroll of colomns*/
   int screenrows;         /**< Terminal height*/
   int screencols;         /**< Terminal width*/
-  int numrows;            /**< Number of rows contained */
-  erow *row;              /**< Store all the rows printed */
+
+  ScreenLayout layout;
+  
   int dirty;
-  char *filename;
+  int prefix_state;
   char status_msg[80];
   time_t status_msg_time;
   struct termios orig_termios; /**< Terminal communication interface */
+
+  struct const_t constantes;
+  int quit_times_buffer;
+
+  char *init_file_path;
+  FILE *fd_init_file;
+  Lisp env;
+  LispContext ctx;     /** Lisp context */
+  Lisp ctx_data;       /** Lisp data context */
+  LispError ctx_error; /** Lisp ctx error */
+
+  struct keyBind_t *key_binds;
+  int number_of_keybinds;
+
+  struct prefix_t *prefix;
+  int number_of_prefix;
+
+  struct buffer_t buffers[64];
+  int number_of_buffer;
+
+  theme_t theme;
 };
 
 /**
@@ -47,4 +156,6 @@ struct abuf {
   int len; /**< Length of the text */
 };
 
+extern struct editorConfig E;
+
 #endif

include/define.h

@@ -24,8 +24,6 @@ enum editorKey {
 
 #define ABUF_INIT {NULL, 0}
 
-#define BELUGA_VERSION "1.0"
-#define TAB_LENGTH 4
-#define QUIT_TIMES 1
+#define BELUGA_VERSION "1.1"
 
 #endif // DEFINE_H_

include/editor_op.h

@@ -2,10 +2,12 @@
 #define EDITOR_OP_H_
 
 #include "data.h"
-void editorInsertChar(struct editorConfig *E, int c);
+void bufferInsertChar(int c);
 
-void editorInsertNewLine(struct editorConfig *E);
+void bufferInsertNewLine();
 
-void editorDelChar(struct editorConfig *E);
+void bufferDelChar();
+
+void editorSetStatusMessage(const char *fmt, ...);
 
 #endif // EDITOR_OP_H_

include/file_io.h

@@ -8,10 +8,15 @@
 #include <stdlib.h>
 #include <sys/types.h>
 
-char *editorRowsToString(struct editorConfig *E, int *buffer_len);
+char *bufferRowsToString(struct buffer_t *buf,int *buffer_len);
 
-void editorOpen(struct editorConfig *E, char *filename);
 
-void editorSave(struct editorConfig *E);
+void editorCloseFile(void);
+
+void editorOpen(struct buffer_t *buffer);
+
+void editorSave();
+
+void bufferFind(struct buffer_t *buf);
 
 #endif // FILE_IO_H_

include/init.h

@@ -1,6 +1,7 @@
 #ifndef INIT_H_
 #define INIT_H_
 
+#include "builtins.h"
 #include "data.h"
 #include "terminal.h"
 #include <stdio.h>
@@ -10,6 +11,8 @@
  * \brief Job's function is to initialize all the fields of editorConfig.
  * */
 
-void initEditor(struct editorConfig *E);
+void initBuiltins();
+
+void initEditor();
 
 #endif // INIT_H_

include/input.h

@@ -5,6 +5,7 @@
 #include "define.h"
 #include "output.h"
 #include "terminal.h"
+#include "builtins.h"
 #include <unistd.h>
 
 // KEYS keycode
@@ -19,15 +20,19 @@
 // END \x1b[4~ || <esc>[8~ || <esc>[F  || <esc>OF
 // DELETE \x1b[3~
 
-char *editorPrompt(struct editorConfig *E, char *prompt);
+char *editorPrompt(char *prompt, char * PlaceHolder, char bPathMode);
 
-void editorMoveCursor(struct editorConfig *E, int key);
+char *key_to_string(int key);
+
+int editorMoveCursor(int key);
+
+int executeKeyBind(char *key_sequence);
 
 /**
  * \fn void editorProcessKeypress()
  * \brief Get the last key input and do the proper action.
  */
 
-void editorProcessKeypress(struct editorConfig *E);
+void editorProcessKeypress();
 
 #endif // INPUT_H_

include/output.h

@@ -1,11 +1,7 @@
 #ifndef OUTPUT_H_
 #define OUTPUT_H_
 
-#include "append_buffer.h"
 #include "data.h"
-#include "define.h"
-#include "row_op.h"
-#include <stdio.h>
 #include <unistd.h>
 
 /**
@@ -13,16 +9,14 @@
  * \brief Draws left rows of the editor.
  */
 
-void editorDrawRows(struct editorConfig *E, struct abuf *ab);
+void editorDrawRows(struct abuf *ab);
 
-void editorRefreshScreen(struct editorConfig *E);
+void editorRefreshScreen();
 
-void editorScroll(struct editorConfig *E);
+void editorScroll();
 
-void editorDrawStatusBar(struct editorConfig *E, struct abuf *ab);
+void editorDrawStatusBar(struct abuf *ab);
 
-void editorDrawMessageBar(struct editorConfig *E, struct abuf *ab);
-
-void editorSetStatusMessage(struct editorConfig *E, const char *fmt, ...);
+void editorDrawMessageBar(struct abuf *ab);
 
 #endif // OUTPUT_H_

include/row_op.h

@@ -8,21 +8,22 @@
 #include <time.h>
 #include <unistd.h>
 
-int editorRowCxToRx(erow *row, int cursor_x);
+int bufferRowCxToRx(frow *row, int cursor_x);
 
-void editorUpdateRow(erow *row);
+int bufferRowRxToCx(frow *row, int rx);
 
-void editorInsertRow(struct editorConfig *E, int at, char *s, size_t len);
+void bufferUpdatfrow(frow *row);
 
-void editorFreeRow(erow *row);
+void bufferInsertRow(struct buffer_t *buffer, int at, char *s, size_t len);
 
-void editorDelRow(struct editorConfig *E, int at);
+void bufferFrefrow(frow *row);
 
-void editorRowInsertChar(struct editorConfig *E, erow *row, int at, int c);
+void bufferDelRow(struct buffer_t *buffer, int at);
 
-void editorRowAppendString(struct editorConfig *E, erow *row, char *s,
-                           size_t len);
+void bufferRowInsertChar(struct buffer_t *buffer, frow *row, int at, int c);
 
-void editorRowDelchar(struct editorConfig *E, erow *row, int at);
+void bufferRowAppendString(struct buffer_t *buffer, frow *row, char *s, size_t len);
+
+void bufferRowDelchar(struct buffer_t *buffer, frow *row, int at);
 
 #endif // ROW_OP_H_

include/split_screen.h

@@ -0,0 +1,62 @@
+/**
+ * @file split_screen.h
+ * @brief Split screen management for displaying multiple buffers
+ */
+
+#ifndef SPLIT_SCREEN_H_
+#define SPLIT_SCREEN_H_
+
+#include "data.h"
+
+/**
+ * @brief Initializes split screen system
+ */
+void splitScreenInit(void);
+
+/**
+ * @brief Splits screen vertically (left-right)
+ * @param buffer_id_left Buffer ID for left pane
+ * @param buffer_id_right Buffer ID for right pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenVertical(int buffer_id_left, int buffer_id_right);
+
+/**
+ * @brief Splits screen horizontally (top-bottom)
+ * @param buffer_id_top Buffer ID for top pane
+ * @param buffer_id_bottom Buffer ID for bottom pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom);
+
+/**
+ * @brief Returns to single buffer fullscreen
+ */
+void splitScreenUnify(void);
+
+/**
+ * @brief Switches active pane (focus moves between splits)
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSwitchPane(void);
+
+/**
+ * @brief Updates the active pane's buffer
+ * @param buffer_id New buffer ID for active pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSetPaneBuffer(int buffer_id);
+
+/**
+ * @brief Gets current screen layout
+ * @return Pointer to current ScreenLayout
+ */
+ScreenLayout *splitScreenGetLayout(void);
+
+/**
+ * @brief Gets active pane
+ * @return Pointer to active EditorPane
+ */
+EditorPane *splitScreenGetActivePane(void);
+
+#endif

include/syntax_highlighter.h

@@ -0,0 +1,23 @@
+#ifndef SYNTAX_HIGHLIGHTER_H_
+#define SYNTAX_HIGHLIGHTER_H_
+
+#include "color.h"
+
+// Color codes that only affect foreground, preserving your background color
+#define COLOR_RESET         "\x1b[39m"            // Reset all (4 bytes)
+
+// Token types
+typedef enum {
+  TOKEN_KEYWORD,
+  TOKEN_TYPE,
+  TOKEN_STRING,
+  TOKEN_COMMENT,
+  TOKEN_NUMBER,
+  TOKEN_OPERATOR,
+  TOKEN_DEFAULT
+} TokenType;
+
+char *highlight_line(const char * line, int *length);
+
+#endif
+

include/terminal.h

@@ -21,9 +21,9 @@
 
 void die(const char *s);
 
-void disableRawMode(struct editorConfig *E);
+void disableRawMode();
 
-void enableRawMode(struct editorConfig *E);
+void enableRawMode();
 
 int editorReadKey();
 

install.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+
+echo "--- Welcome to Beluga installer ---"
+read -p "Do you want to start the installation ? (Y/n)" confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1
+
+# Check dependencies
+
+if ! command -v "meson" &>/dev/null; then
+    echo "❌ Error: meson not found. Please install it first."
+    exit 1
+fi
+
+
+# Create config files
+
+echo "Create config files ..."
+mkdir -pv ~/.beluga/
+mkdir -pv ~/.beluga/assets/
+cp -rv ./assets/beluga.txt ~/.beluga/assets/
+mkdir -pv ~/.beluga/packages/
+mkdir -pv ~/.beluga/config/
+
+read -p "Do you want to replace your config file or keep it (init.lisp.bak) / (init.lisp.new) ? (Y/n)" confirm
+if [[ "$confirm" =~ ^[Yy]$ ]]; then
+    mv ~/.beluga/config/init.lisp  ~/.beluga/config/init.lisp.bak
+    cp -rv ./config/init.lisp ~/.beluga/config/
+else
+    cp -rv ./config/init.lisp ~/.beluga/config/init.lisp.new
+fi
+
+
+# Compile the project
+
+echo "Start compilation ..."
+meson setup build/
+meson compile -C build/
+
+# Add to path
+echo "Adding beluga to the path"
+sudo cp -f ./build/beluga /usr/local/bin/
+
+echo "Installation finish"
+echo "Check ~/.beluga/config/init.lisp for customization"

main.c

@@ -5,6 +5,13 @@
  * interactions. \version 0.1 \date 21 septembre 2024
  */
 
+#include "include/buffer.h"
+#include "include/split_screen.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
 #define _DEFAULT_SOURCE
 #define _BSD_SOURCE
 #define _GNU_SOURCE
@@ -13,24 +20,35 @@
 #include "include/file_io.h"
 #include "include/init.h"
 #include "include/input.h"
-#include "include/output.h"
+#include "include/editor_op.h"
 #include "include/terminal.h"
 
+struct editorConfig E;
+
 int main(int argc, char *argv[]) {
 
-  struct editorConfig E;
+  char * splash_screen = (char *) calloc(256, sizeof(char));
   
-  enableRawMode(&E);
-  initEditor(&E);
+  enableRawMode();
+  initEditor();
   if (argc >= 2) {
-    editorOpen(&E, argv[1]);
+    EditorPane *active = splitScreenGetActivePane();
+    active->buffer_id = bufferCreate(argv[1]);
+  } else {
+    strcat(splash_screen, getenv("HOME"));
+    strcat(splash_screen, "/.beluga/assets/beluga.txt");
+    fprintf(stderr, "%s\n", splash_screen);
+    EditorPane *active = splitScreenGetActivePane();
+    active->buffer_id = bufferCreate(splash_screen);
   }
+  //free(splash_screen);
+
+  editorSetStatusMessage("HELP: Ctrl-x Ctrl-s = save | Ctrl-x Ctrl-c = quit");
 
-  editorSetStatusMessage(&E, "HELP: Ctrl-S = save | Ctrl-Q = quit");
 
   while (1) {
-    editorRefreshScreen(&E);
-    editorProcessKeypress(&E);
+    editorRefreshScreen();
+    editorProcessKeypress();
   }
   return 0;
 }

meson.build

@@ -0,0 +1,32 @@
+project('beluga', 'c',
+  version : '2.3',
+  default_options : [
+    'c_std=none',
+  ]
+)
+
+cc = meson.get_compiler('c')
+m = cc.find_library('m', required: false)            
+
+# Source files
+src_files = files(
+  'main.c',
+  'src/append_buffer.c',
+  'src/editor_op.c',
+  'src/syntax_highlighter.c',
+  'src/file_io.c',
+  'src/init.c',
+  'src/input.c',
+  'src/output.c',
+  'src/row_op.c',
+  'src/terminal.c',
+  'src/builtins.c',
+  'src/buffer.c',
+  'src/split_screen.c'
+)
+
+# Executable
+executable('beluga',
+  src_files,
+  dependencies: [m]
+)

src/append_buffer.c

@@ -1,5 +1,7 @@
 #include "../include/append_buffer.h"
 
+extern struct editorConfig E;
+
 void abAppend(struct abuf *ab, const char *s, int len) {
   char *new = realloc(ab->b, ab->len + len);
 

src/buffer.c

@@ -0,0 +1,236 @@
+/**
+ * @file buffer.c
+ * @brief Buffer management implementation for multiple open files
+ */
+
+#include "../include/buffer.h"
+#include "../include/file_io.h"
+#include "../include/editor_op.h"
+#include "../include/data.h"
+#include "include/split_screen.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+extern struct editorConfig E;
+
+/**
+ * @brief Finds a buffer by filename
+ * @param filename The filename to search for
+ * @return Buffer ID if found, -1 if not found
+ */
+static int bufferFindByFilename(const char *filename) {
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        if (E.buffers[i].filename != NULL && 
+            strcmp(E.buffers[i].filename, filename) == 0) {
+            return E.buffers[i].buffer_id;
+        }
+    }
+    return -1;
+}
+
+/**
+ * @brief Finds a buffer by ID
+ * @param buffer_id The buffer ID to find
+ * @return Pointer to buffer, NULL if not found
+ */
+struct buffer_t *bufferFindById(int buffer_id) {
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        if (E.buffers[i].buffer_id == buffer_id) {
+            return &E.buffers[i];
+        }
+    }
+    return NULL;
+}
+
+/**
+ * @brief Creates a new buffer for a file
+ * @details Allocates buffer slot, loads file content, saves buffer metadata.
+ * If file is already open, switches to existing buffer instead.
+ * @param filename Path to the file
+ * @return Buffer ID on success, -1 on failure
+ */
+int bufferCreate(const char *filename) {
+    // Check if file is already open
+    int existing_id = bufferFindByFilename(filename);
+    if (existing_id != -1) {
+        return bufferSwitch(existing_id);
+    }
+    
+    // Check if we have space for more buffers
+    if (E.number_of_buffer >= 64) {
+        editorSetStatusMessage("Error: maximum buffers reached (64)");
+        return -1;
+    }
+    
+    // Initialize new buffer
+    struct buffer_t *new_buf = &E.buffers[E.number_of_buffer];
+    new_buf->buffer_id = E.number_of_buffer;
+    new_buf->filename = strdup(filename);
+    new_buf->type = FILE_BUFF;
+    new_buf->state = READ_AND_WRITE;
+    new_buf->x = 0;
+    new_buf->y = 0;
+    new_buf->row_offset = 0;
+    new_buf->col_offset = 0;
+    new_buf->dirty = 0;  // New file starts clean
+    
+    // Load file content using existing editorOpen
+    editorOpen(new_buf);
+    
+    E.number_of_buffer++;
+    
+    editorSetStatusMessage("Opened: %s (buffer %d)", filename, new_buf->buffer_id);
+    return new_buf->buffer_id;
+}
+
+/**
+ * @brief Switches to a specific buffer by ID
+ * @details Saves current buffer state, loads target buffer content and state.
+ * @param buffer_id The buffer ID to switch to
+ * @return 0 on success, -1 on failure
+ */
+int bufferSwitch(int buffer_id) {
+    struct buffer_t *target = bufferFindById(buffer_id);
+    if (target == NULL) {
+      E.layout.panes[E.layout.active_pane].buffer_id = buffer_id;
+        editorSetStatusMessage("Error: buffer not found");
+        return -1;
+    }
+        
+    
+    editorSetStatusMessage("Switched to: %s (buffer %d)", 
+                          target->filename, buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Closes a buffer by ID
+ * @details Frees buffer resources and removes from buffer list.
+ * Prompts to save unsaved changes. If closing current buffer,
+ * switches to next available buffer.
+ * @param buffer_id The buffer ID to close
+ * @return 0 on success, -1 on failure
+ */
+int bufferClose(int buffer_id) {
+    struct buffer_t *buf = bufferFindById(buffer_id);
+    if (buf == NULL) {
+        editorSetStatusMessage("Error: buffer not found");
+        return -1;
+    }
+
+    EditorPane * active = splitScreenGetActivePane();
+    
+    // If this is the current buffer, find next buffer to switch to
+    if (active->buffer_id == buffer_id) {
+        int next_id = -1;
+        
+        // Try to switch to next buffer
+        for (int i = 0; i < E.number_of_buffer; i++) {
+            if (E.buffers[i].buffer_id != buffer_id) {
+                next_id = E.buffers[i].buffer_id;
+                break;
+            }
+        }
+        
+        if (next_id != -1) {
+            bufferSwitch(next_id);
+        } else {
+            // No other buffers, clear editor
+            editorCloseFile();
+        }
+    }
+    
+    // Free buffer resources
+    free(buf->filename);
+    buf->filename = NULL;
+    buf->buffer_id = -1;
+    
+    // Remove from buffer list by shifting
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        if (E.buffers[i].buffer_id == buffer_id) {
+            for (int j = i; j < E.number_of_buffer - 1; j++) {
+                E.buffers[j] = E.buffers[j + 1];
+            }
+            E.number_of_buffer--;
+            break;
+        }
+    }
+    
+    editorSetStatusMessage("Closed buffer %d", buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Gets the current active buffer
+ * @return Pointer to current buffer_t, NULL if none
+ */
+struct buffer_t *bufferGetCurrent(void) {
+  EditorPane * active = splitScreenGetActivePane();
+    return bufferFindById(active->buffer_id);
+}
+
+/**
+ * @brief Lists all open buffers
+ * @details Prints buffer information to status message
+ * @return Number of open buffers
+ */
+int bufferListAll(void) {
+    if (E.number_of_buffer == 0) {
+        editorSetStatusMessage("No buffers open");
+        return 0;
+    }
+    
+    char buf[256] = "";
+    int offset = 0;
+    EditorPane * active = splitScreenGetActivePane();
+    
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        struct buffer_t *b = &E.buffers[i];
+        char marker = (b->buffer_id == active->buffer_id) ? '*' : ' ';
+        offset += snprintf(&buf[offset], sizeof(buf) - offset,
+                          "%c%d:%s ", marker, b->buffer_id, 
+                          b->filename ? b->filename : "[No Name]");
+    }
+    
+    editorSetStatusMessage("Buffers: %s", buf);
+    return E.number_of_buffer;
+}
+
+/**
+ * @brief Saves current buffer to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSave(void) {
+    EditorPane * active = splitScreenGetActivePane();
+    if (active->buffer_id == -1) {
+        editorSetStatusMessage("Error: no buffer active");
+        return -1;
+    }
+    
+    editorSave();
+    return 0;
+}
+
+/**
+ * @brief Saves all buffers to disk
+ * @details Iterates through all buffers, saves each one
+ * @return 0 on success, -1 on failure
+ */
+int bufferSaveAll(void) {
+    int saved = 0;
+    int failed = 0;
+    
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        if (bufferSwitch(E.buffers[i].buffer_id) == 0) {
+            if (E.dirty && bufferSave() == 0) {
+                saved++;
+            }
+        } else {
+            failed++;
+        }
+    }
+    
+    editorSetStatusMessage("Saved %d buffers (%d failed)", saved, failed);
+    return (failed == 0) ? 0 : -1;
+}

src/builtins.c

@@ -0,0 +1,513 @@
+/**
+ * @file builtins.c
+ * @brief Built-in Lisp functions for editor operations
+ * @details Provides Lisp bindings for core editor functionality including
+ * cursor movement, file operations, keybinding management, and text manipulation
+ */
+
+#include "../include/builtins.h"
+#include "../include/data.h"
+#include "../include/define.h"
+#include "../include/editor_op.h"
+#include "../include/file_io.h"
+#include "../include/input.h"
+#include "../include/row_op.h"
+#include "../include/buffer.h"
+#include "../include/split_screen.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * @brief Finds a prefix configuration by name
+ * @details Searches the prefix array for a prefix matching the given name.
+ * Returns the first prefix (default) if no match is found.
+ * @param prefix_name Name of the prefix to search for (max 64 chars)
+ * @return Matching prefix_t structure, or E.prefix[0] if not found
+ * @note Updates global editor state E
+ */
+struct prefix_t find_prefix(const char prefix_name[64]) {
+  int i = E.number_of_prefix + 1;
+  while (i--) {
+    if (!strcmp(prefix_name, E.prefix[i].prefix_name)) {
+      return E.prefix[i];
+    }
+  }
+  return E.prefix[0];
+}
+
+/**
+ * @brief Lisp function to bind a command to a key sequence
+ * @details Registers a keybinding with an associated Lisp command and optional
+ * prefix modifier. Dynamically extends the keybind array.
+ * @param args Lisp list of 3 arguments: (key-sequence command prefix-name)
+ *        - key_sequence (string): The key or key combination to bind
+ *        - command (Lisp): The Lisp command/function to execute
+ *        - prefix_name (string): Prefix modifier name
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (key_binds array)
+ */
+Lisp mapKey(Lisp args, LispError *e, LispContext ctx) {
+  /*
+   * 3 arguments keybind command prefix
+   */
+  const char *key_sequence = lisp_string(lisp_car(args));
+  args = lisp_cdr(args);
+  // second argument
+  Lisp func = lisp_car(args);
+
+  E.key_binds = (struct keyBind_t *)realloc(
+      E.key_binds, ++E.number_of_keybinds * sizeof(struct keyBind_t));
+  E.key_binds[E.number_of_keybinds - 1].key_sequence =
+      (char *)malloc(50 * sizeof(char));
+
+  strncpy(E.key_binds[E.number_of_keybinds - 1].key_sequence, key_sequence, 50);
+
+  E.key_binds[E.number_of_keybinds - 1].command = func;
+
+  // Third argument
+  args = lisp_cdr(args);
+  const char *prefix_name = lisp_string(lisp_car(args));
+  struct prefix_t prefix = find_prefix(prefix_name);
+
+  E.key_binds[E.number_of_keybinds - 1].prefix_id = prefix.prefix_id;
+  
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to move cursor in a specified direction
+ * @details Moves the editor cursor up, down, left, or right based on direction string.
+ * @param args Lisp list with one argument: direction string
+ *        - "u": up, "d": down, "r": right, "l": left
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return Lisp boolean indicating whether movement was valid
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp moveCursor(Lisp args, LispError *e, LispContext ctx) {
+  const char *direction = lisp_string(lisp_car(args));
+  int is_in = 0;
+  switch (direction[0]) {
+  case 'u':
+    is_in = editorMoveCursor(ARROW_UP);
+    break;
+  case 'd':
+    is_in = editorMoveCursor(ARROW_DOWN);
+    break;
+  case 'r':
+    is_in = editorMoveCursor(ARROW_RIGHT);
+    break;
+  case 'l':
+    is_in = editorMoveCursor(ARROW_LEFT);
+    break;
+  }
+  fprintf(stderr, "move lisp %d\n", is_in);
+  return lisp_make_bool(is_in);
+}
+
+/**
+ * @brief Frees all dynamically allocated editor structures
+ * @details Releases memory for prefix table, keybinds, filename, and all rows.
+ * Called during shutdown to prevent memory leaks.
+ * @note Updates global editor state E
+ */
+void free_structs(void) {
+  int i, j;
+  free(E.prefix);
+  for (i = 0; i < E.number_of_keybinds; ++i) {
+    free(E.key_binds[i].key_sequence);
+  }
+  free(E.key_binds);
+  // free layout
+  free(E.layout.panes);
+
+  // Free buffers
+  for (i = 0; i < E.number_of_buffer; ++i) {
+    free(E.buffers[i].filename);
+    for (j = 0; j < E.buffers[i].numrows; ++j) {
+      free(E.buffers[i].row[j].render);
+      free(E.buffers[i].row[j].chars);
+    }
+    free(E.buffers[i].row);
+  }
+  
+  free(E.init_file_path);
+  fclose(E.fd_init_file);
+  
+}
+
+/**
+ * @brief Lisp function to quit the editor
+ * @details Closes editor with unsaved changes protection. Prompts user to confirm
+ * quit after multiple attempts if file is dirty. Cleans up resources and restores terminal.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null() (never returns on successful exit)
+ * @note Calls exit(0) to terminate program
+ * @note Updates quit_times_buffer counter
+ * @see free_structs()
+ */
+Lisp editorQuit(Lisp args, LispError *e, LispContext ctx) {
+  if (E.dirty && E.quit_times_buffer > 0) {
+    editorSetStatusMessage("WARNING! Changes hasn't been saved. Press Ctrl-Q "
+                           "another time to quit.");
+    --E.quit_times_buffer;
+    return lisp_null();
+  }
+  free_structs();
+  write(STDOUT_FILENO, "\x1b[2J", 4);
+  write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
+  disableRawMode();
+  lisp_shutdown(E.ctx);
+  exit(0);
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to save the current file
+ * @details Wrapper around editorSave() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorSave()
+ */
+
+Lisp l_editorSplitScreenVertical(Lisp args, LispError *e, LispContext ctx) {
+  if (E.number_of_buffer >= 2) {
+        splitScreenVertical(E.buffers[0].buffer_id, E.buffers[1].buffer_id);
+    } else {
+        editorSetStatusMessage("Need at least 2 buffers open");
+    }
+  return lisp_null();
+}
+
+Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx) {
+
+  editorSave();
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to insert a new line at cursor
+ * @details Wrapper around editorInsertNewLine() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorInsertNewLine()
+ */
+Lisp l_editorInsertNewLine(Lisp args, LispError *e, LispContext ctx) {
+
+  bufferInsertNewLine();
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to insert a tab (spaces) at cursor
+ * @details Inserts TAB_LENGTH spaces at the current cursor position.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Uses E.constantes.TAB_LENGTH for indentation width
+ */
+Lisp l_editorInserTab(Lisp args, LispError *e, LispContext ctx) {
+
+  for (int i = 0; i<E.constantes.TAB_LENGTH; ++i) {
+    bufferInsertChar(' ');
+  }
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to move cursor to beginning of line
+ * @details Moves cursor to column 0 of the current line.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ */
+Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx) {
+  E.layout.panes[E.layout.active_pane].cursor_x = 0;
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to move cursor to end of line
+ * @details Moves cursor to the end of the current line content.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ */
+Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  if (active->cursor_y < buf->numrows) {
+    active->cursor_x = buf->row[active->cursor_y].size;
+  }
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to delete character before cursor
+ * @details Wrapper around editorDelChar() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorDelChar()
+ */
+Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx) {
+  bufferDelChar();
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to move cursor up by one screen
+ * @details Scrolls up one full screen height, moving cursor to top of visible area.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp editorMoveCursorPageUp(Lisp args, LispError *e, LispContext ctx) {
+  EditorPane *active = splitScreenGetActivePane();
+  active->cursor_y = active->row_offset;
+  int times = E.screenrows;
+  while (--times) {
+    editorMoveCursor(ARROW_UP);
+  }
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to move cursor down by one screen
+ * @details Scrolls down one full screen height, moving cursor to bottom of visible area.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
+  active->cursor_y = active->row_offset + E.screenrows - 1;
+  if (active->cursor_y > buffer->numrows) {
+    active->cursor_y = buffer->numrows;
+  }
+  int times = E.screenrows;
+  while (--times) {
+    editorMoveCursor(ARROW_DOWN);
+  }
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to open a file
+ * @details Prompts user for filename and opens the file for editing.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorOpen()
+ * @see editorPrompt()
+ */
+Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx) {
+  char *filename = editorPrompt("Open : %s", getenv("PWD"), 1);
+  if (filename){
+    //    editorOpen(filename);
+    EditorPane *active = splitScreenGetActivePane();
+    active->buffer_id = bufferCreate(filename);
+  }
+  free(filename);
+  
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to insert a character
+ * @details Extracts a character from Lisp string argument and inserts it at cursor.
+ * @param args Lisp list with one string argument
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Uses first character of the string argument
+ */
+Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx) {
+  char c = lisp_string(lisp_car(args))[0];
+  bufferInsertChar(c);
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to load and execute a package
+ * @details Loads a Lisp package from the user's packages directory
+ * (~/.beluga/packages/<package_name>/init.lisp) and evaluates it.
+ * @param args Lisp list with one argument: package name (string)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Package files must be valid Lisp code
+ * @note Package directory defaults to ~/.beluga/packages/
+ */
+Lisp addPackage(Lisp args, LispError *e, LispContext ctx) {
+  const char *package_name = lisp_string(lisp_car(args));
+  fprintf(stderr, "%s\n", package_name);
+  char *package_dir = (char *)calloc(256, sizeof(char));
+  FILE *fd_package = NULL;
+  strcat(package_dir, getenv("HOME"));
+  strcat(package_dir, "/.beluga/packages/");
+  strcat(package_dir, package_name);
+  strcat(package_dir, "/init.lisp");
+  fprintf(stderr, "%s\n", package_dir);
+  fd_package = fopen(package_dir, "r");
+  lisp_eval(lisp_read_file(fd_package, &E.ctx_error, E.ctx), &E.ctx_error,
+            E.ctx);
+  fclose(fd_package);
+  free(package_dir);
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to delete the current row
+ * @details Removes the line at the current cursor position.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorDelRow()
+ */
+Lisp editorDelRow_L(Lisp args, LispError *e, LispContext ctx) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
+  bufferDelRow(buffer, active->cursor_y);
+  return lisp_null();
+}
+
+Lisp editorSwitchNextBuffer(Lisp args, LispError *e, LispContext ctx) {
+  fprintf(stderr, "switch buffer\n");
+  if (E.number_of_buffer > 0) {
+    EditorPane *active = splitScreenGetActivePane();
+    int next_idx = (active->buffer_id + 1) % E.number_of_buffer;
+    active->buffer_id = next_idx;
+    }
+
+  return lisp_null();
+}
+
+Lisp editorSwitchNextPane(Lisp args, LispError *e, LispContext ctx) {
+  splitScreenSwitchPane();
+  return lisp_null();
+}
+
+Lisp editorUnifiedPanes(Lisp args, LispError *e, LispContext ctx) {
+  if (E.layout.num_panes - 1) {
+    splitScreenUnify();
+  }
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to search for text
+ * @details Wrapper around editorFind() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorFind()
+ */
+Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx) {
+  fprintf(stderr, "LispFind\n");
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
+  bufferFind(buffer);
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to read character at cursor
+ * @details Returns the character at the current cursor position as a Lisp character.
+ * Returns 'a' if at end of line.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return Lisp character object representing the character at cursor
+ */
+Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx) {
+  Lisp returned_char;
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
+  if (buffer->row[active->cursor_y].render[active->cursor_x] == 0) {
+    returned_char = lisp_make_char('a');
+  } else {
+    
+     returned_char = lisp_make_char(buffer->row[active->cursor_y].render[active->cursor_x]); 
+  }
+  return returned_char;
+}
+
+/**
+ * @brief Lisp function to set the current prefix mode
+ * @details Changes the editor's prefix state to a named prefix, affecting which
+ * keybindings are active. Updates status message to show active prefix.
+ * @param args Lisp list with one argument: prefix name (string)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (prefix_state)
+ * @see find_prefix()
+ */
+Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx) {
+  /*
+   * Set the prefix state of editor to the prefix in argument
+   */
+  const char *prefix_name = lisp_string(lisp_car(args));
+  struct prefix_t prefix = find_prefix(prefix_name);
+  E.prefix_state = prefix.prefix_id;
+  editorSetStatusMessage("prefix %s", prefix.prefix_name);
+  fprintf(stderr, "%s set\n", prefix_name);
+
+  return lisp_null();
+}
+
+/**
+ * @brief Lisp function to define a new prefix modifier
+ * @details Registers a named prefix modifier that can be used with keybindings
+ * to create context-aware command sequences (e.g., Ctrl-X as a prefix).
+ * @param args Lisp list with one argument: prefix name (string, max 64 chars)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (prefix array)
+ */
+Lisp editorPrefix(Lisp args, LispError *e, LispContext ctx) {
+  E.prefix = (struct prefix_t *)realloc(E.prefix, (++(E.number_of_prefix) + 1) *
+                                                      sizeof(struct prefix_t));
+  E.prefix[E.number_of_prefix].prefix_id = E.number_of_prefix;
+  strncpy(E.prefix[E.number_of_prefix].prefix_name, lisp_string(lisp_car(args)),
+          64);
+  return lisp_null();
+}

src/editor_op.c

@@ -1,44 +1,82 @@
+#include <stdarg.h>
+
 #include "../include/editor_op.h"
 #include "../include/row_op.h"
+#include "include/buffer.h"
+#include "include/data.h"
+#include "include/split_screen.h"
 
-void editorInsertChar(struct editorConfig *E, int c) {
-  if (E->cursor_y == E->numrows) {
-    editorInsertRow(E, E->numrows, "", 0);
-  }
-  editorRowInsertChar(E, &E->row[E->cursor_y], E->cursor_x, c);
-  E->cursor_x++;
+
+extern struct editorConfig E;
+
+
+/**
+ * @brief Sets a temporary status message for display
+ * @details Formats and stores a message that will be displayed in the message
+ * bar for 5 seconds. Uses printf-style variable argument formatting.
+ * @param fmt Printf-style format string
+ * @param ... Variable arguments for format string
+ * @note Updates global editor state E (status_msg, status_msg_time)
+ * @see editorDrawMessageBar()
+ */
+void editorSetStatusMessage(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  vsnprintf(E.status_msg, sizeof(E.status_msg), fmt, ap);
+  va_end(ap);
+  E.status_msg_time = time(NULL);
 }
 
-void editorInsertNewLine(struct editorConfig *E) {
-  erow *row;
-  if (!E->cursor_x) {
-    editorInsertRow(E, E->cursor_y, "", 0);
+
+void bufferInsertChar(int c) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+    if (active->cursor_y == buf->numrows) {
+      bufferInsertRow(buf, buf->numrows, "", 0);
+    }
+    bufferRowInsertChar(buf, &buf->row[active->cursor_y], active->cursor_x, c);
+    active->cursor_x++;
+}
+
+void bufferInsertNewLine() {
+  /*
+   * Add new line and place the cursor at the beginning of it
+   */
+  fprintf(stderr, "Inserting new line\n");
+    EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  frow *row;
+  if (!active->cursor_x) {
+    bufferInsertRow(buf, active->cursor_y, "", 0);
   } else {
-    row = &E->row[E->cursor_y];
-    editorInsertRow(E, E->cursor_y + 1, &row->chars[E->cursor_x],
-                    row->size - E->cursor_x);
-    row = &E->row[E->cursor_y];
-    row->size = E->cursor_x;
+    row = &buf->row[active->cursor_y];
+    bufferInsertRow(buf, active->cursor_y + 1, &row->chars[active->cursor_x],
+                    row->size - active->cursor_x);
+    row = &buf->row[active->cursor_y];
+    row->size = active->cursor_x;
     row->chars[row->size] = '\0';
-    editorUpdateRow(row);
+    bufferUpdatfrow(row);
   }
-  ++E->cursor_y;
-  E->cursor_x = 0;
+  ++active->cursor_y;
+  active->cursor_x = 0;
+  fprintf(stderr, "Insert new line done\n");
 }
 
-void editorDelChar(struct editorConfig *E) {
-  erow *row;
-  if (E->cursor_y == E->numrows || !(E->cursor_x || E->cursor_y)) {
+void bufferDelChar() {
+  frow *row;
+    EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  if (active->cursor_y == buf->numrows || !(active->cursor_x || active->cursor_y)) {
     return;
   }
-  row = &E->row[E->cursor_y];
-  if (E->cursor_x > 0) {
-    editorRowDelchar(E, row, E->cursor_x - 1);
-    --E->cursor_x;
+  row = &buf->row[active->cursor_y];
+  if (active->cursor_x > 0) {
+    bufferRowDelchar(buf, row, active->cursor_x - 1);
+    --active->cursor_x;
   } else {
-    E->cursor_x = E->row[E->cursor_y - 1].size;
-    editorRowAppendString(E, &E->row[E->cursor_y - 1], row->chars, row->size);
-    editorDelRow(E, E->cursor_y);
-    --E->cursor_y;
+    active->cursor_x = buf->row[active->cursor_y - 1].size;
+    bufferRowAppendString(buf, &buf->row[active->cursor_y - 1], row->chars, row->size);
+    bufferDelRow(buf, active->cursor_y);
+    --active->cursor_y;
   }
 }

src/file_io.c

@@ -1,6 +1,17 @@
+/**
+ * @file file_io.c
+ * @brief File I/O operations module for the Beluga text editor
+ * @details Handles file loading, saving, searching, and buffer management.
+ * Provides functionality for opening/closing files, persisting changes to disk,
+ * and searching for text patterns within the document.
+ */
+
 #include "../include/file_io.h"
+#include "../include/editor_op.h"
 #include "../include/input.h"
-#include "../include/output.h"
+#include "include/buffer.h"
+#include "include/data.h"
+#include "include/split_screen.h"
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -8,35 +19,86 @@
 #include <time.h>
 #include <unistd.h>
 
-char *editorRowsToString(struct editorConfig *E, int *buffer_len) {
+extern char *strdup(const char *);
+extern ssize_t getline(char **restrict lineptr, size_t *restrict n,
+                       FILE *restrict stream);
+extern int ftruncate(int fd, off_t length);
+extern struct editorConfig E;
+
+/**
+ * @brief Converts all editor rows to a single string buffer
+ * @details Concatenates all row content into a single allocated buffer with
+ * newlines between rows. Useful for file saving and buffer operations.
+ * @param buffer_len Pointer to integer where total buffer length will be stored
+ * @return Pointer to dynamically allocated buffer containing all row data.
+ *         Rows are separated by newline characters.
+ * @note Caller is responsible for freeing the returned buffer
+ */
+char *bufferRowsToString(struct buffer_t *buf, int *buffer_len) {
   int tot_len = 0;
   int j;
-  char *buf;
+  char *buffer;
   char *p;
 
-  for (j = 0; j < E->numrows; ++j) {
-    tot_len += E->row[j].size + 1;
+  for (j = 0; j < buf->numrows; ++j) {
+    tot_len += buf->row[j].size + 1;
   }
   *buffer_len = tot_len;
-  buf = malloc(tot_len);
-  p = buf;
-  for (j = 0; j < E->numrows; ++j) {
-    memcpy(p, E->row[j].chars, E->row[j].size);
-    p += E->row[j].size;
+  buffer = malloc(tot_len);
+  p = buffer;
+  for (j = 0; j < buf->numrows; ++j) {
+    memcpy(p, buf->row[j].chars, buf->row[j].size);
+    p += buf->row[j].size;
     *p = '\n';
     p++;
   }
 
-  return buf;
+  return buffer;
 }
 
-void editorOpen(struct editorConfig *E, char *filename) {
+/**
+ * @brief Closes the current file and resets editor state
+ * @details Clears all rows, resets cursor position, scroll offsets, and file
+ * metadata. Does not prompt to save unsaved changes.
+ * @note Updates global editor state E
+ */
+void editorCloseFile(void) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  active->cursor_x = 0;
+  active->cursor_y = 0;
+  active->rx = 0;
+  active->row_offset = 0;
+  active->col_offset = 0;
+  for (int i = 0; i < buf->numrows; ++i) {
+    free(buf->row[i].chars);
+    free(buf->row[i].render);
+  }
+  buf->numrows = 0;
+  free(buf->row);
+  buf->row = NULL;
+  buf->dirty = 0;
+  free(buf->filename);
+  buf->filename = NULL;
+  E.status_msg[0] = '\0';
+  E.status_msg_time = 0;
+}
+
+/**
+ * @brief Opens a file for editing
+ * @details Loads file content into editor rows, one line per row. If another
+ * file is already open, it is closed first (without saving). File is opened in
+ * a+ (read/append) mode to allow both reading and modification.
+ * @param filename Path to the file to open (relative or absolute)
+ * @note Updates global editor state E
+ * @note Calls die() on file open failure
+ * @note Newline characters are stripped from loaded lines
+ * @see editorInsertRow()
+ */
+void editorOpen(struct buffer_t* buffer) {
   FILE *fp;
 
-  free(E->filename);
-  E->filename = strdup(filename);
-
-  fp = fopen(filename, "r");
+  fp = fopen(buffer->filename, "a+");
   if (!fp)
     die("fopen");
 
@@ -49,38 +111,83 @@ void editorOpen(struct editorConfig *E, char *filename) {
            (line[line_len - 1] == '\n' || line[line_len - 1] == '\r')) {
       --line_len;
     }
-    editorInsertRow(E, E->numrows, line, line_len);
+    bufferInsertRow(buffer, buffer->numrows, line, line_len);
+    free(line);
+    line = NULL;
   }
   free(line);
   fclose(fp);
-  E->dirty = 0;
+  E.dirty = 0;
 }
 
-void editorSave(struct editorConfig *E) {
+/**
+ * @brief Saves the current file to disk
+ * @details Prompts for filename if not set, converts all rows to a buffer,
+ * writes to disk using open/ftruncate/write, and updates dirty flag.
+ * Displays status messages on success or failure.
+ * @note Updates global editor state E (dirty flag)
+ * @note If no filename is set, prompts user via editorPrompt()
+ * @note Uses O_RDWR | O_CREAT with mode 0644
+ * @see editorRowsToString()
+ */
+void editorSave() {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
   int len;
   char *buf;
   int fd;
-  if (E->filename == NULL) {
-    E->filename = editorPrompt(E, "Save as: %s (ESC to cancel)");
-    if (E->filename == NULL) {
-      editorSetStatusMessage(E, "Save aborted");
+  if (buffer->filename == NULL) {
+    buffer->filename = editorPrompt("Save as: %s (ESC to cancel)", "", 1);
+    if (buffer->filename == NULL) {
+      editorSetStatusMessage("Save aborted");
       return;
     }
   }
-  buf = editorRowsToString(E, &len);
-  fd = open(E->filename, O_RDWR | O_CREAT, 0644);
+  buf = bufferRowsToString(buffer, &len);
+  fd = open(buffer->filename, O_RDWR | O_CREAT, 0644);
   if (fd != -1) {
     if (ftruncate(fd, len) != -1) {
       if (write(fd, buf, len) == len) {
         close(fd);
         free(buf);
-        E->dirty = 0;
-        editorSetStatusMessage(E, "%d bytes written to disk", len);
+        E.dirty = 0;
+        editorSetStatusMessage("%d bytes written to disk", len);
         return;
       }
     }
     close(fd);
   }
   free(buf);
-  editorSetStatusMessage(E, "Can't save! I/O error: %s", strerror(errno));
+  editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
+}
+
+/**
+ * @brief Searches for a string in the document
+ * @details Prompts user for a search query, then searches forward from current
+ * cursor position. Updates cursor position to the first match found.
+ * @note Updates global editor state E (cursor position, row_offset)
+ * @note Search is case-sensitive and operates on rendered line content
+ * @note Searches begin from the line after current cursor position
+ * @see editorPrompt()
+ * @see editorRowRxToCx()
+ */
+void bufferFind(struct buffer_t *buf) {
+  fprintf(stderr, "searching\n");
+  char *query = editorPrompt("Search: %s (ESC to cancel)", "", 0);
+  EditorPane *active = splitScreenGetActivePane();
+
+  if (query == NULL)
+    return;
+  int i;
+  for (i = active->cursor_y + 1; i < buf->numrows; i++) {
+    frow *row = &buf->row[i];
+    char *match = strstr(row->render, query);
+    if (match) {
+      active->cursor_y = i;
+      active->cursor_x = bufferRowRxToCx(row, match - row->render);
+      buf->row_offset = buf->numrows;
+      break;
+    }
+  }
+  free(query);
 }

src/init.c

@@ -1,19 +1,137 @@
 #include "../include/init.h"
+#include "../include/builtins.h"
+#include "../include/color.h"
+#include "../include/data.h"
+#include "../include/terminal.h"
+#include "include/split_screen.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
-void initEditor(struct editorConfig *E) {
-  E->cursor_x = 0;
-  E->cursor_y = 0;
-  E->rx = 0;
-  E->row_offset = 0;
-  E->col_offset = 0;
-  E->numrows = 0;
-  E->row = NULL;
-  E->dirty = 0;
-  E->filename = NULL;
-  E->status_msg[0] = '\0';
-  E->status_msg_time = 0;
-  if (getWindowSize(&E->screenrows, &E->screencols) == -1) {
+#define LISP_IMPLEMENTATION
+#include "../include/lisp.h"
+#include "../include/lisp_lib.h"
+
+struct editorConfig;
+
+void registerBuiltin(char *key_sequence, LispCFunc f) {
+  lisp_env_define(E.ctx.p->env, lisp_make_symbol(key_sequence, E.ctx),
+                  lisp_make_func(f), E.ctx);
+}
+
+void initBuiltins() {
+  // Registering C functions as lisp macro
+  registerBuiltin("move-cursor", moveCursor);
+  registerBuiltin("map-key", mapKey);
+  registerBuiltin("editor-quit", editorQuit);
+  registerBuiltin("editor-save", l_editorSave);
+  registerBuiltin("editor-insert-new-line", l_editorInsertNewLine);
+  registerBuiltin("move-cursor-beg-line", moveCursorBeginLine);
+  registerBuiltin("move-cursor-end-line", moveCursorEndLine);
+  registerBuiltin("editor-delete-previous-char", deletePreviousChar);
+  registerBuiltin("move-cursor-page-up", editorMoveCursorPageUp);
+  registerBuiltin("move-cursor-page-down", editorMoveCursorPageDown);
+  registerBuiltin("editor-open-file", editorOpenFile);
+  registerBuiltin("editor-insert-char", editorPrintC);
+  registerBuiltin("add-package", addPackage);
+  registerBuiltin("editor-del-row", editorDelRow_L);
+  registerBuiltin("buffer-find", bufferFind_L);
+  registerBuiltin("editor-read-char", editorReadChar_L);
+  registerBuiltin("add-prefix", editorPrefix);
+  registerBuiltin("editor-set-prefix", editorSetPrefix);
+  registerBuiltin("editor-insert-tab", l_editorInserTab);
+  registerBuiltin("editor-switch-next-buffer", editorSwitchNextBuffer);
+  registerBuiltin("editor-split-screen-vertical", l_editorSplitScreenVertical);
+  registerBuiltin("editor-switch-next-pane", editorSwitchNextPane);
+  registerBuiltin("editor-unify-panes", editorUnifiedPanes);
+}
+
+void initConfig() {
+
+  E.ctx = lisp_init();
+  E.env = lisp_env(E.ctx);
+  lisp_lib_load(E.ctx);
+  // Init builtins lisp functions
+  initBuiltins();
+
+  // Read config file
+  E.ctx_data = lisp_read_file(E.fd_init_file, &E.ctx_error, E.ctx);
+  if (E.ctx_error != LISP_ERROR_NONE) {
+    die("init failed");
+  }
+  lisp_eval(E.ctx_data, &E.ctx_error, E.ctx);
+}
+
+void init_theme() {
+  E.constantes.THEME = (char *)lisp_string(
+      lisp_eval(lisp_read("THEME", &E.ctx_error, E.ctx), &E.ctx_error, E.ctx));
+  if (strcmp(E.constantes.THEME, "dark") == 0) {
+    E.theme.BACKGROUND_COLOR = ANSI_BG_RGB(40, 44, 52);
+    E.theme.COLOR_KEYWORD = ANSI_FG_RGB(198, 120, 221);
+    E.theme.COLOR_TYPE = ANSI_FG_RGB(97, 175, 239);
+    E.theme.COLOR_STRING = ANSI_FG_RGB(152, 195, 121);
+    E.theme.COLOR_COMMENT = ANSI_FG_RGB(92, 99, 112);
+    E.theme.COLOR_NUMBER = ANSI_FG_RGB(209, 154, 102);
+    E.theme.COLOR_DEFAULT = ANSI_FG_RGB(171, 178, 191);
+  } else {
+    E.theme.BACKGROUND_COLOR = ANSI_BG_RGB(250, 251, 252);
+    E.theme.COLOR_KEYWORD = ANSI_FG_RGB(166, 38, 164);
+    E.theme.COLOR_TYPE = ANSI_FG_RGB(4, 90, 180);
+    E.theme.COLOR_STRING = ANSI_FG_RGB(80, 161, 79);
+    E.theme.COLOR_COMMENT = ANSI_FG_RGB(152, 152, 152);
+    E.theme.COLOR_NUMBER = ANSI_FG_RGB(206, 102, 54);
+    E.theme.COLOR_DEFAULT = ANSI_FG_RGB(86, 89, 90);
+  }
+}
+
+void initEditor() {
+
+  if (getWindowSize(&E.screenrows, &E.screencols) == -1) {
     die("getWindowSize");
   }
-  E->screenrows -= 2;
+  E.screenrows -= 2;
+
+  
+  // Init graphics variables
+  splitScreenInit();
+  EditorPane *active = splitScreenGetActivePane();
+  active->cursor_x = 0;
+  active->cursor_y = 0;
+  active->rx = 0;
+  active->row_offset = 0;
+  active->col_offset = 0;
+  E.init_file_path = (char *)calloc(256, sizeof(char));
+  strcat(E.init_file_path, getenv("HOME"));
+  strcat(E.init_file_path, "/.beluga/config/init.lisp");
+  E.fd_init_file = fopen(E.init_file_path, "r");
+
+  // Status bar
+  E.status_msg[0] = '\0';
+  E.status_msg_time = 0;
+
+  // Key binds
+  E.number_of_keybinds = 0;
+  E.number_of_prefix = 0;
+  // General prefix is 0 (no prefix)
+  E.prefix = (struct prefix_t *)malloc(sizeof(struct prefix_t));
+  E.prefix[0].prefix_id = 0;
+  strncpy(E.prefix[0].prefix_name, "no-prefix", 64);
+  E.prefix_state = 0;
+
+  initConfig();
+
+  init_theme();
+
+  // To modify
+
+  E.constantes.TAB_LENGTH =
+      (int)lisp_eval(lisp_read("TAB-LENGTH", &E.ctx_error, E.ctx), &E.ctx_error,
+                     E.ctx)
+          .val.int_val;
+  E.constantes.QUIT_TIMES =
+      (int)lisp_eval(lisp_read("QUIT-TIMES", &E.ctx_error, E.ctx), &E.ctx_error,
+                     E.ctx)
+          .val.int_val;
+
+  E.quit_times_buffer = E.constantes.QUIT_TIMES;
 }

src/input.c

@@ -1,42 +1,156 @@
 #include "../include/input.h"
+#include "../include/define.h"
 #include "../include/editor_op.h"
-#include "../include/file_io.h"
 #include "../include/output.h"
+#include "include/buffer.h"
+#include "include/data.h"
+#include "include/split_screen.h"
 #include <ctype.h>
+#include <dirent.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
+#include <string.h>
+#include <sys/stat.h>
+
+extern struct editorConfig E;
 
 /**
- * \fn char * editorPrompt(struct editorConfig *E, char *prompt)
- * \brief Return user input in a prompt when enter is hit. */
+ * @file input.c
+ * @brief Input handling module for the Beluga text editor
+ * @details Manages user input processing, key bindings, cursor movement, and file path completion
+ */
 
-char *editorPrompt(struct editorConfig *E, char *prompt) {
+/**
+ * @brief Returns the first file completion match for the given path
+ * @details Searches the directory containing the given path prefix and returns
+ * the first file or directory entry that matches the filename prefix.
+ * Appends a trailing slash for directory entries.
+ * @param path The file path to complete (can be relative or absolute)
+ * @return Pointer to the completed file path (dynamically allocated), or NULL if:
+ *         - path ends with '/' (already a directory)
+ *         - no matching entries found
+ *         - directory cannot be opened
+ * @note Caller is responsible for freeing the returned string
+ * @note Uses static buffer internally; may return stale pointers across calls
+ */
+const char *file_completion(const char *path) {
+  DIR *dir;
+  struct dirent *entry;
+  char directory[128];
+  char predict[128];
+  const char *last_slash;
+  int predict_len = 0;
+  size_t dir_len;
+
+  // path is a directory
+  if (path[strlen(path) - 1] == '/') {
+    fprintf(stderr, "[FILE COMP] is dir\n");
+    strncpy(directory, path, 128);
+  }
+
+  // Find dir name
+  last_slash = strrchr(path, '/');
+  if (last_slash) {
+    dir_len = last_slash - path + 1; // length of dir_path
+    strncpy(directory, path, dir_len);
+    predict_len = strlen(path) - dir_len;
+    strncpy(predict, last_slash + 1, predict_len);
+    directory[dir_len] = '\0';
+    predict[predict_len] = '\0';
+    fprintf(stderr, "%s %s\n", directory, predict);
+  } else {
+    fprintf(stderr, "[FILE COMP] dir not found\n");
+    return strdup(path);
+  }
+
+  dir = opendir(directory);
+  if (!dir)
+    return strdup(path);
+
+  while ((entry = readdir(dir)) != NULL) {
+    if (strncmp(entry->d_name, predict, predict_len) == 0) {
+      static char full_path[512];
+      snprintf(full_path, sizeof(full_path), "%s%s", directory, entry->d_name);
+
+      struct stat st;
+      if (stat(full_path, &st) == 0 && S_ISDIR(st.st_mode)) {
+        strcat(full_path, "/"); // add slash for directories
+      }
+      closedir(dir);
+      
+      return strdup(full_path);
+    }
+  }
+
+  // Cleanup when no more entries
+  closedir(dir);
+  dir = NULL;
+  free(entry);
+  fprintf(stderr, "[FILE COMP] no entries\n");
+  return strdup(path);
+}
+
+/**
+ * @brief Displays an interactive prompt and returns user input
+ * @details Allows the user to enter text in a prompt with optional path completion
+ * via Tab key. Supports backspace, delete, and escape key handling. Dynamically
+ * allocates memory for the input buffer.
+ * @param prompt The prompt message format string (printf-style)
+ * @param placeHolder Initial text to display in the input buffer
+ * @param bPathMode If non-zero, enables Tab key file path completion
+ * @return Pointer to the user-entered text (dynamically allocated), or NULL if:
+ *         - User pressed ESC to cancel
+ *         - Input buffer is empty when Enter is pressed
+ * @note Caller is responsible for freeing the returned string
+ * @note Uses editorReadKey() for input and editorRefreshScreen() for display
+ */
+char *editorPrompt(char *prompt, char *placeHolder, char bPathMode) {
   size_t buf_size = 128;
   char *buf = malloc(buf_size);
   size_t buf_len = 0;
   int c = 0;
   buf[0] = '\0';
+  strcpy(buf, placeHolder);
+  buf_len = strlen(placeHolder);
 
   while (1) {
-    editorSetStatusMessage(E, prompt, buf);
-    editorRefreshScreen(E);
+    editorSetStatusMessage(prompt, buf);
+    editorRefreshScreen();
     c = editorReadKey();
     if (c == DEL_KEY || c == CTRL_KEY('h') || c == BACKSPACE) {
       if (buf_len != 0) {
         buf[--buf_len] = '\0';
       }
     } else if (c == ESCAPE) {
-      fprintf(stderr, "escape");
-      editorSetStatusMessage(E, "");
+      editorSetStatusMessage("");
       free(buf);
       return NULL;
     } else if (c == '\r') {
       if (buf_len != 0) {
-        editorSetStatusMessage(E, "");
+        editorSetStatusMessage("");
         return buf;
       }
+    } else if (bPathMode && c == '\t') {
+      char path[128];
+      char *pwd;
+      if (buf[0] != '/') {
+        pwd = getenv("PWD");
+        fprintf(stderr, "%s\n", pwd);
+        memcpy(path, pwd, strlen(pwd));
+        path[strlen(pwd)] = '/';
+        strncat(path, buf, buf_len);
+      } else {
+        strcpy(path, buf);
+      }
+      memset(buf, 0, 128);
+      buf_len = 0;
+      char * buf_complete = (char *) file_completion(path);
+      strcpy(buf, buf_complete);
+      free(buf_complete);
+      buf_len = strlen(buf);
+      buf[buf_len] = '\0';
+
     } else if (!iscntrl(c) && c < 128) {
       if (buf_len == buf_size - 1) {
         buf_size *= 2;
@@ -48,121 +162,178 @@ char *editorPrompt(struct editorConfig *E, char *prompt) {
   }
 }
 
-void editorMoveCursor(struct editorConfig *E, int key) {
-  erow *row = (E->cursor_y >= E->numrows) ? NULL : &E->row[E->cursor_y];
-  int row_len;
+/**
+ * @brief Converts a key code to its string representation
+ * @details Translates raw key codes (including special keys, control keys,
+ * and regular characters) into human-readable string formats suitable for
+ * display and keybinding configuration.
+ * @param key The key code to convert
+ * @return Pointer to static buffer containing the string representation.
+ *         Examples: "ENTER", "ARROW-UP", "CTRL-a", "TAB", "DELETE", etc.
+ * @note Returns pointer to static buffer; string is overwritten on next call
+ * @note Non-printable characters are formatted as "KEY-<number>"
+ */
+char *key_to_string(int key) {
+  static char key_str[32];
+
+  char tmp[10];
+  sprintf(tmp, "%d", key);
+
+  // First test enter key
+
+  if (key == '\r') {
+    strcpy(key_str, "ENTER");
+  } else if (key == '\t') {
+    strcpy(key_str, "TAB");
+  } else if (key >= 1 && key <= 26) { // CTRL keys
+    snprintf(key_str, sizeof(key_str), "CTRL-%c", 'a' + key - 1);
+  } else {
     switch (key) {
-  case ARROW_RIGHT:
-    if (row && E->cursor_x < row->size) {
-      ++E->cursor_x;
-    } else if (row && E->cursor_x == row->size) {
-      E->cursor_y++;
-      E->cursor_x = 0;
-    }
+    case ARROW_UP:
+      strcpy(key_str, "ARROW-UP");
       break;
     case ARROW_DOWN:
-    if (E->cursor_y < E->numrows) {
-      ++E->cursor_y;
-    }
-    break;
-  case ARROW_UP:
-    if (E->cursor_y != 0) {
-      --E->cursor_y;
-    }
+      strcpy(key_str, "ARROW-DOWN");
       break;
     case ARROW_LEFT:
-    if (E->cursor_x != 0) {
-      --E->cursor_x;
-    } else if (E->cursor_y > 0) {
-      --E->cursor_y;
-      E->cursor_x = E->row[E->cursor_y].size;
-    }
+      strcpy(key_str, "ARROW-LEFT");
       break;
-  }
-
-  row = (E->cursor_y >= E->numrows) ? NULL : &E->row[E->cursor_y];
-  row_len = row ? row->size : 0;
-  if (E->cursor_x > row_len) {
-    E->cursor_x = row_len;
-  }
-}
-
-void editorProcessKeypress(struct editorConfig *E) {
-  static int quit_times = QUIT_TIMES;
-  int c = editorReadKey();
-  int times;
-
-  switch (c) {
-
-  case '\r':
-    editorInsertNewLine(E);
+    case ARROW_RIGHT:
+      strcpy(key_str, "ARROW-RIGHT");
       break;
-  case CTRL_KEY('q'):
-    if (E->dirty && quit_times > 0) {
-      editorSetStatusMessage(E,
-                             "WARNING! Changes hasn't been saved. Press Ctrl-Q "
-                             "another time to quit.");
-      --quit_times;
-      return;
-    }
-    write(STDOUT_FILENO, "\x1b[2J", 4);
-    write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
-    disableRawMode(E);
-    exit(0);
-    break;
-
-  case CTRL_KEY('s'):
-    editorSave(E);
-    break;
-
-  case BEG_LINE:
-    E->cursor_x = 0;
-    break;
-
-  case END_LINE:
-    if (E->cursor_y < E->numrows) {
-      E->cursor_x = E->row[E->cursor_y].size;
-    }
-    break;
-
-  case BACKSPACE:
-  case CTRL_KEY('h'):
-  case DEL_KEY:
-    if (c == DEL_KEY) {
-      editorMoveCursor(E, ARROW_RIGHT);
-    }
-    editorDelChar(E);
-    break;
-
     case PAGE_UP:
-  case PAGE_DOWN: {
-    if (c == PAGE_UP) {
-      E->cursor_y = E->row_offset;
-    } else if (c == PAGE_DOWN) {
-      E->cursor_y = E->row_offset + E->screenrows - 1;
-      if (E->cursor_y > E->numrows) {
-        E->cursor_y = E->numrows;
-      }
-    }
-    times = E->screenrows;
-    while (--times) {
-      editorMoveCursor(E, c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
-    }
-  } break;
-
-  case ARROW_UP:
-  case ARROW_DOWN:
-  case ARROW_LEFT:
-  case ARROW_RIGHT:
-    editorMoveCursor(E, c);
+      strcpy(key_str, "PAGE-UP");
+      fprintf(stderr, "pagr up\n");
       break;
+    case PAGE_DOWN:
+      strcpy(key_str, "PAGE-DOWN");
+      break;
+    case DEL_KEY:
+      strcpy(key_str, "DEL");
 
-  case CTRL_KEY('l'):
+      break;
+    case BACKSPACE:
+      strcpy(key_str, "BACKSPACE");
+      break;
+    case '\r':
+      strcpy(key_str, "ENTER");
+      break;
     case '\x1b':
+      strcpy(key_str, "ESCAPE");
+      break;
+    case BEG_LINE:
+      strcpy(key_str, "HOME");
+      break;
+    case END_LINE:
+      strcpy(key_str, "END");
       break;
     default:
-    editorInsertChar(E, c);
+      // For regular characters
+      if (isprint(key)) {
+        snprintf(key_str, sizeof(key_str), "%c", key);
+      } else {
+        snprintf(key_str, sizeof(key_str), "KEY-%d", key);
+      }
+    }
+  }
+  return key_str;
+}
+
+/**
+ * @brief Moves the cursor based on arrow key input
+ * @details Updates cursor position (E.cursor_x, E.cursor_y) based on the given
+ * key direction. Handles line wrapping and boundary conditions. Prevents cursor
+ * from exceeding line lengths.
+ * @param key The arrow key code (ARROW_UP, ARROW_DOWN, ARROW_LEFT, ARROW_RIGHT)
+ * @return 1 if cursor movement was valid, 0 if cursor was constrained to line boundary
+ * @note Updates global editor state E
+ */
+int editorMoveCursor(int key) {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  frow *row = (active->cursor_y + active->row_offset >= buf->numrows) ? NULL : &buf->row[active->cursor_y + active->row_offset];
+  int row_len;
+  int x = active->cursor_x + active->col_offset;
+  int y = active->cursor_y + active->row_offset;
+  switch (key) {
+  case ARROW_RIGHT:
+    if (row && x < row->size) {
+        active->cursor_x++;
+
+    } else if (row && y == row->size) {
+      active->cursor_y++;
+      active->cursor_x = 0;
+    }
+    break;
+  case ARROW_DOWN:
+    if (y < buf->numrows) {
+
+      active->cursor_y++;
+    }
+    break;
+  case ARROW_UP:
+    if (y != 0) {
+      --active->cursor_y;
+    }
+    break;
+  case ARROW_LEFT:
+    if (x != 0) {
+      --active->cursor_x;
+    } else if (y > 0) {
+      --active->cursor_y;
+      active->cursor_x = buf->row[y].size;
+    }
     break;
   }
-  quit_times = QUIT_TIMES;
+    
+    
+  return 1;
+}
+
+/**
+ * @brief Executes the command bound to a key sequence
+ * @details Searches the keybinding table for a matching key sequence and
+ * prefix state, then evaluates the associated Lisp command.
+ * @param key_sequence The string representation of the key sequence
+ * @return 1 if a matching keybinding was found and executed, 0 otherwise
+ * @note Updates global editor state E (prefix_state)
+ * @note Uses Lisp interpreter to evaluate bound commands
+ */
+int executeKeyBind(char *key_sequence) {
+  int i;
+  int previous_state = 0;
+  fprintf(stderr, "pressed %s\n", key_sequence);
+  for (i = 0; i < E.number_of_keybinds; ++i) {
+    if (!strcmp(key_sequence, E.key_binds[i].key_sequence)) {
+      if (E.prefix_state != E.key_binds[i].prefix_id) {
+        continue;
+      }
+      previous_state = E.prefix_state;
+      // It's a symbol, create a function call
+      lisp_eval(lisp_cons(E.key_binds[i].command, lisp_null(), E.ctx),
+                &E.ctx_error, E.ctx);
+      if (E.prefix_state == previous_state)
+        E.prefix_state = 0;
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/**
+ * @brief Processes a single keypress from the user
+ * @details Reads a key, checks if it matches any registered keybinding,
+ * and either executes the bound command or inserts the character. Resets
+ * the quit buffer counter on successful key processing.
+ * @note Updates global editor state E
+ * @note Calls editorReadKey() to get input and editorInsertChar() for unbound keys
+ */
+void editorProcessKeypress() {
+  int c = editorReadKey();
+
+  if (executeKeyBind(key_to_string(c))) {
+    return;
+  }
+  bufferInsertChar(c);
+  E.quit_times_buffer = E.constantes.QUIT_TIMES;
 }

src/output.c

@@ -1,87 +1,236 @@
+/**
+ * @file output.c
+ * @brief Screen rendering and output module for the Beluga text editor
+ * @details Handles all screen updates, cursor positioning, status bar
+ * rendering, and display synchronization using ANSI escape sequences
+ */
+
 #include "../include/output.h"
-#include <stdarg.h>
+#include "../include/append_buffer.h"
+#include "../include/buffer.h"
+#include "../include/data.h"
+#include "../include/define.h"
+#include "../include/row_op.h"
+#include "../include/split_screen.h"
+#include "../include/syntax_highlighter.h"
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
-void editorDrawRows(struct editorConfig *E, struct abuf *ab) {
-  int y;
+extern struct editorConfig E;
+
+/**
+ * @brief Renders a single pane with its buffer content
+ */
+static void editorDrawPane(struct abuf *ab, EditorPane *pane) {
+  if (pane == NULL || pane->buffer_id < 0)
+    return;
+
+  struct buffer_t *buf = bufferFindById(pane->buffer_id);
+  if (buf == NULL)
+    return;
+
+  // Draw content for this pane
+  for (int y = 0; y < pane->height; y++) {
+    int file_row = y + pane->row_offset;
+
+    // Position cursor at start of pane row
+    char pos_buf[32];
+    int pos_len = snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH",
+                           pane->start_row + y + 1, pane->start_col + 1);
+    abAppend(ab, pos_buf, pos_len);
+
+    // Apply background color (6 bytes for RGB format)
+    abAppend(ab, E.theme.BACKGROUND_COLOR, strlen(E.theme.BACKGROUND_COLOR));
+
+    int chars_printed = 0;
+
+    if (file_row >= buf->numrows) {
+      // Empty line - show tilde
+      if (buf->numrows == 0 && y == pane->height / 3) {
         char welcome[80];
-  int welcome_len;
-  int padding;
-  int len;
-  int file_row;
-  for (y = 0; y < E->screenrows; ++y) {
-    file_row = y + E->row_offset;
-    if (file_row >= E->numrows) {
-      if (E->numrows == 0 && y == E->screenrows / 3) {
-        welcome_len =
-            snprintf(welcome, sizeof(welcome),
-                     "Beluga text editor -- version %s", BELUGA_VERSION);
-        if (welcome_len > E->screencols) {
-          welcome_len = E->screencols;
-        }
-        padding = (E->screencols - welcome_len) / 2;
+        int welcome_len =
+            snprintf(welcome, sizeof(welcome), "Buffer %d", pane->buffer_id);
+        if (welcome_len > pane->width)
+          welcome_len = pane->width;
+
+        int padding = (pane->width - welcome_len) / 2;
         if (padding) {
           abAppend(ab, "~", 1);
-          --padding;
+          chars_printed++;
+          padding--;
         }
-        while (padding--) {
+        while (padding-- && chars_printed < pane->width) {
           abAppend(ab, " ", 1);
+          chars_printed++;
         }
         abAppend(ab, welcome, welcome_len);
+        chars_printed += welcome_len;
       } else {
         abAppend(ab, "~", 1);
+        chars_printed++;
       }
     } else {
-      len = E->row[file_row].rsize - E->col_offset;
-      if (len < 0)
-        len = 0;
-      if (len > E->screencols)
-        len = E->screencols;
-      abAppend(ab, &E->row[file_row].render[E->col_offset], len);
+      // Render line with syntax highlighting, constrain to pane width
+      int start_offset = pane->col_offset;
+      int visible_len = buf->row[file_row].rsize - start_offset;
+      if (visible_len < 0)
+        visible_len = 0;
+      if (visible_len > pane->width)
+        visible_len = pane->width;
+
+      if (buf->filename[strlen(buf->filename) - 1] == 'c') {
+        int byte_len_to_print;
+
+        char *highlighted = highlight_line(
+            &buf->row[file_row].render[start_offset], &byte_len_to_print);
+
+        // Print only up to pane width
+
+        abAppend(ab, highlighted, byte_len_to_print);
+        free(highlighted);
+      } else {
+        abAppend(ab, &buf->row[file_row].render[start_offset], buf->row[file_row].rsize);
       }
-    abAppend(ab, ERASE_END_LINE, 3);
-    abAppend(ab, "\r\n", 2);
+
+      chars_printed = visible_len;
+    }
+
+    // Fill remaining space with background color to pane width
+    abAppend(ab, E.theme.BACKGROUND_COLOR, strlen(E.theme.BACKGROUND_COLOR));
+    while (chars_printed < pane->width) {
+      abAppend(ab, " ", 1);
+      chars_printed++;
+    }
+
+    // Restore background color at end of line
   }
 }
 
-void editorScroll(struct editorConfig *E) {
-  E->rx = E->cursor_x;
-  if (E->cursor_y < E->numrows) {
-    E->rx = editorRowCxToRx(&E->row[E->cursor_y], E->cursor_x);
-  }
+/**
+ * @brief Renders all panes based on current split configuration
+ */
+static void editorDrawAllPanes(struct abuf *ab) {
+  ScreenLayout *layout = splitScreenGetLayout();
 
-  if (E->cursor_y < E->row_offset) {
-    E->row_offset = E->cursor_y;
+  if (layout->num_panes == 1) {
+    // Single pane fullscreen
+    editorDrawPane(ab, &layout->panes[0]);
+  } else if (layout->num_panes == 2) {
+    // Draw both panes
+    for (int i = 0; i < 2; i++) {
+      editorDrawPane(ab, &layout->panes[i]);
+
+      // Draw pane border/divider if not the last pane
+      if (layout->mode == SPLIT_VERTICAL && i == 0) {
+        // Draw vertical divider
+        int divider_col = layout->panes[0].width;
+        for (int y = 0; y < layout->panes[0].height; y++) {
+          char pos_buf[32];
+          snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH", y + 1, divider_col);
+          abAppend(ab, pos_buf, strlen(pos_buf));
+          abAppend(ab, "\x1b[1m|\x1b[0m", 9); // Bold pipe divider
+        }
+      } else if (layout->mode == SPLIT_HORIZONTAL && i == 0) {
+        // Draw horizontal divider
+        int divider_row = layout->panes[0].height;
+        char pos_buf[32];
+        snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH", divider_row + 1, 1);
+        abAppend(ab, pos_buf, strlen(pos_buf));
+        for (int x = 0; x < E.screencols; x++) {
+          abAppend(ab, "\x1b[1m-\x1b[0m", 9); // Bold dash divider
         }
-  if (E->cursor_y >= E->row_offset + E->screenrows) {
-    E->row_offset = E->cursor_y - E->screenrows + 1;
       }
-  if (E->rx < E->col_offset) {
-    E->col_offset = E->rx;
     }
-  if (E->rx >= E->col_offset + E->screencols) {
-    E->col_offset = E->rx - E->screencols + 1;
   }
 }
 
-void editorDrawStatusBar(struct editorConfig *E, struct abuf *ab) {
+/**
+ * @brief Updates scroll offsets to keep cursor visible on screen
+ * @details Adjusts E.row_offset and E.col_offset to ensure the cursor remains
+ * within the visible viewport. Also updates E.rx (rendered x-coordinate).
+ * @note Updates global editor state E
+ * @see editorRowCxToRx()
+ */
+void editorScroll() {
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  active->rx = active->cursor_x;
+
+  fprintf(stderr, "%d %d / %d %d\n", active->cursor_x, active->col_offset,
+          active->cursor_y, active->row_offset);
+
+  if (active->cursor_x < 0) {
+    active->cursor_x = 0;
+    active->col_offset = active->col_offset == 0 ? 0 : --active->col_offset;
+  }
+
+  if (active->cursor_y < 0) {
+    active->cursor_y = 0;
+    active->row_offset = active->row_offset == 0 ? 0 : --active->row_offset;
+  }
+
+  if (active->cursor_x == active->width) {
+
+    active->cursor_x--;
+    active->col_offset++;
+  }
+
+  if (active->cursor_y == active->height) {
+
+    active->cursor_y--;
+    active->row_offset++;
+  }
+}
+
+/**
+ * @brief Renders the status bar at the bottom of the screen
+ * @details Displays filename, line count, dirty flag, and current cursor
+ * position in an inverted color bar. Right-aligns the cursor position
+ * indicator.
+ * @param ab Pointer to append buffer structure for accumulating output
+ * @note Uses ANSI escape codes for color inversion
+ */
+void editorDrawStatusBar(struct abuf *ab) {
   int len, render_len;
   char status[80], render_status[80];
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
 
   abAppend(ab, "\x1b[7m", 4); // inverting colors
-  len = snprintf(status, sizeof(status), "%.20s - %d lines%s",
-                 E->filename ? E->filename : "[No Name]", E->numrows,
-                 E->dirty ? "*" : "");
-  render_len = snprintf(render_status, sizeof(render_status), "%d/%d",
-                        E->cursor_y + 1, E->numrows);
-  if (len > E->screencols) {
-    len = E->screencols;
+
+  const char *mode_str = "";
+  ScreenLayout *layout = splitScreenGetLayout();
+  if (layout->mode == SPLIT_VERTICAL)
+    mode_str = " [V-SPLIT]";
+  else if (layout->mode == SPLIT_HORIZONTAL)
+    mode_str = " [H-SPLIT]";
+
+  // Build buffer status showing all buffers with dirty indicators
+  char buf_status[200] = "";
+  int offset = 0;
+  for (int i = 0; i < E.number_of_buffer; i++) {
+    struct buffer_t *b = &E.buffers[i];
+    char marker = (b->buffer_id == active->buffer_id) ? '>' : ' ';
+    char dirty_marker = b->dirty ? '*' : ' ';
+    offset += snprintf(&buf_status[offset], sizeof(buf_status) - offset,
+                       "%c%d:%s%c ", marker, b->buffer_id,
+                       b->filename ? b->filename : "[No Name]", dirty_marker);
   }
+
+  len = snprintf(status, sizeof(status), "%s%s", buf_status, mode_str);
+
+  render_len = snprintf(render_status, sizeof(render_status), "%d/%d",
+                        active->cursor_y + 1, buf->numrows);
+
+  if (len > E.screencols) {
+    len = E.screencols;
+  }
+
   abAppend(ab, status, len);
-  while (len < E->screencols) {
-    if (E->screencols - len == render_len) {
+  while (len < E.screencols) {
+    if (E.screencols - len == render_len) {
       abAppend(ab, render_status, render_len);
       break;
     } else {
@@ -89,47 +238,67 @@ void editorDrawStatusBar(struct editorConfig *E, struct abuf *ab) {
       ++len;
     }
   }
+
   abAppend(ab, "\x1b[m", 3); // normal text mode
   abAppend(ab, "\r\n", 2);
 }
 
-void editorDrawMessageBar(struct editorConfig *E, struct abuf *ab) {
-  int msg_len = strlen(E->status_msg);
+/**
+ * @brief Renders the message bar below the status bar
+ * @details Displays temporary status messages for a limited time (5 seconds).
+ * Only displays message if within time window and within screen width.
+ * @param ab Pointer to append buffer structure for accumulating output
+ * @note Messages are set by editorSetStatusMessage()
+ */
+void editorDrawMessageBar(struct abuf *ab) {
+  int msg_len = strlen(E.status_msg);
   abAppend(ab, ERASE_END_LINE, 3);
-  if (msg_len > E->screencols) {
-    msg_len = E->screencols;
+  if (msg_len > E.screencols) {
+    msg_len = E.screencols;
   }
-  if (msg_len && time(NULL) - E->status_msg_time < 5) {
-    abAppend(ab, E->status_msg, msg_len);
+  if (msg_len && time(NULL) - E.status_msg_time < 5) {
+    abAppend(ab, E.status_msg, msg_len);
   }
 }
 
-void editorRefreshScreen(struct editorConfig *E) {
-  editorScroll(E);
+/**
+ * @brief Performs complete screen refresh and buffer synchronization
+ * @details Clears screen, redraws all visible content (rows, status bar,
+ * message bar), positions cursor, and writes accumulated buffer to stdout. This
+ * is the main rendering function called each frame.
+ * @note Updates global editor state E (via editorScroll())
+ * @see editorDrawRows()
+ * @see editorDrawStatusBar()
+ * @see editorDrawMessageBar()
+ */
+
+void editorRefreshScreen() {
   struct abuf ab = ABUF_INIT;
   char buf[32];
 
   abAppend(&ab, HIDE_CURSOR, 6);
   abAppend(&ab, CURSOR_TOP_LEFT, 3);
+  abAppend(&ab, E.theme.BACKGROUND_COLOR,
+           strlen(E.theme.BACKGROUND_COLOR)); // RGB background is 12 bytes
 
-  editorDrawRows(E, &ab);
-  editorDrawStatusBar(E, &ab);
-  editorDrawMessageBar(E, &ab);
+  // Draw all panes
+  editorScroll();
+  editorDrawAllPanes(&ab);
 
-  snprintf(buf, sizeof(buf), "\x1b[%d;%dH", (E->cursor_y - E->row_offset) + 1,
-           (E->rx - E->col_offset) + 1);
+  // Draw status bar and message bar
+  editorDrawStatusBar(&ab);
+  editorDrawMessageBar(&ab);
+
+  // Position cursor in active pane
+  EditorPane *active = splitScreenGetActivePane();
+  if (active != NULL) {
+    snprintf(buf, sizeof(buf), "\x1b[%d;%dH",
+             active->cursor_y + active->start_row + 1,
+             active->cursor_x + active->start_col + 1);
     abAppend(&ab, buf, strlen(buf));
+  }
 
   abAppend(&ab, SHOW_CURSOR, 6);
-
   write(STDOUT_FILENO, ab.b, ab.len);
   abFree(&ab);
 }
-
-void editorSetStatusMessage(struct editorConfig *E, const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  vsnprintf(E->status_msg, sizeof(E->status_msg), fmt, ap);
-  va_end(ap);
-  E->status_msg_time = time(NULL);
-}

src/row_op.c

@@ -1,26 +1,41 @@
 #include "../include/row_op.h"
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
-int editorRowCxToRx(erow *row, int cursor_x) {
+extern struct editorConfig E;
+
+int bufferRowCxToRx(frow *row, int cursor_x) {
   int render_x = 0;
   int i;
   for (i = 0; i < cursor_x; ++i) {
     if (row->chars[i] == '\t') {
-      render_x += (TAB_LENGTH - 1) - (render_x % TAB_LENGTH);
+      render_x += (E.constantes.TAB_LENGTH - 1) - (render_x % E.constantes.TAB_LENGTH);
     }
     render_x++;
   }
   return render_x;
 }
 
+int bufferRowRxToCx(frow *row, int rx) {
+  int cur_rx = 0;
+  int cx;
+  for (cx = 0; cx < row->size; cx++) {
+    if (row->chars[cx] == '\t')
+      cur_rx += (E.constantes.TAB_LENGTH - 1) - (cur_rx % E.constantes.TAB_LENGTH);
+    cur_rx++;
+    if (cur_rx > rx) return cx;
+  }
+  return cx;
+}
+
 /**
- * \fn editorUpdateRow(erow *row)
+ * \fn bufferUpdatfrow(frow *row)
  * \brief Copy content of \p row in \p row->render.
  *  */
 
-void editorUpdateRow(erow *row) {
+void bufferUpdatfrow(frow *row) {
   int i, i_render;
   int tabs = 0;
 
@@ -32,8 +47,8 @@ void editorUpdateRow(erow *row) {
   }
 
   free(row->render);
-  row->render = malloc(row->size + tabs * (TAB_LENGTH - 1) +
-                       1); /**< Tabs needs TAB_LENGTH chars so TAB_LENGTH - 1
+  row->render = malloc(row->size + tabs * (E.constantes.TAB_LENGTH - 1) +
+                       1); /**< Tabs needs E.constantes.TAB_LENGTH chars so E.constantes.TAB_LENGTH - 1
                               more than the first already counted. */
 
   // end of counting
@@ -41,7 +56,7 @@ void editorUpdateRow(erow *row) {
   for (i = 0; i < row->size; ++i) {
     if (row->chars[i] == '\t') {
       row->render[i_render++] = ' ';
-      while (i_render % TAB_LENGTH) {
+      while (i_render % E.constantes.TAB_LENGTH) {
         row->render[i_render++] =
             ' '; /**< Addind the right amount of spaces for tabs */
       }
@@ -53,47 +68,54 @@ void editorUpdateRow(erow *row) {
   row->rsize = i_render;
 }
 
-void editorInsertRow(struct editorConfig *E, int at, char *s, size_t len) {
-  if (at < 0 || at > E->numrows) {
+void bufferInsertRow(struct buffer_t *buffer, int at, char *s, size_t len) {
+  
+  if (at < 0 || at > buffer->numrows) {
+    
     return;
   }
+  frow *tmp = (frow *)realloc(buffer->row, sizeof(frow) * (buffer->numrows + 1));
+  if (!tmp) {
+    return;
+  }
+  buffer->row = tmp;
+  memmove(&buffer->row[at + 1], &buffer->row[at], sizeof(frow) * (buffer->numrows - at));
 
-  E->row = realloc(E->row, sizeof(erow) * (E->numrows + 1));
-  memmove(&E->row[at + 1], &E->row[at], sizeof(erow) * (E->numrows - at));
+  buffer->row[at].size = len;
+  buffer->row[at].chars = malloc(len + 1);
+  memcpy(buffer->row[at].chars, s, len);
+  buffer->row[at].chars[len] = '\0';
 
-  E->row[at].size = len;
-  E->row[at].chars = malloc(len + 1);
-  memcpy(E->row[at].chars, s, len);
-  E->row[at].chars[len] = '\0';
+  buffer->row[at].rsize = 0;
+  buffer->row[at].render = NULL;
+  bufferUpdatfrow(&buffer->row[at]);
 
-  E->row[at].rsize = 0;
-  E->row[at].render = NULL;
-  editorUpdateRow(&E->row[at]);
-
-  ++E->numrows;
-  ++E->dirty;
+  ++buffer->numrows;
+  ++buffer->dirty;
 }
 
-void editorFreeRow(erow *row) {
+void bufferFrefrow(frow *row) {
   free(row->render);
   free(row->chars);
 }
 
-void editorDelRow(struct editorConfig *E, int at) {
-  if (at < 0 || at >= E->numrows) {
+void bufferDelRow(struct buffer_t *buffer, int at) {
+  if (at < 0 || at >= buffer->numrows) {
     return;
   }
-  editorFreeRow(&E->row[at]);
-  memmove(&E->row[at], &E->row[at + 1], sizeof(erow) * (E->numrows - at - 1));
-  --E->numrows;
-  ++E->dirty;
+  bufferFrefrow(&buffer->row[at]);
+  memmove(&buffer->row[at], &buffer->row[at + 1], sizeof(frow) * (buffer->numrows - at - 1));
+  --buffer->numrows;
+  ++buffer->dirty;
 }
 
 /**
- * \fn editorRowInsertChar(erow *row, int at, int c)
+ * \fn bufferRowInsertChar(frow *row, int at, int c)
  * \param at Index of where we want to insert the char */
 
-void editorRowInsertChar(struct editorConfig *E, erow *row, int at, int c) {
+void bufferRowInsertChar(struct buffer_t *buffer, frow *row, int at, int c) {
+  if (buffer->state == READ_ONLY)
+    return;
   if (at < 0 || at > row->size) {
     at = row->size;
   }
@@ -101,31 +123,30 @@ void editorRowInsertChar(struct editorConfig *E, erow *row, int at, int c) {
   memmove(&row->chars[at + 1], &row->chars[at], row->size - at + 1);
   ++row->size;
   row->chars[at] = c;
-  editorUpdateRow(row);
-  ++E->dirty;
+  bufferUpdatfrow(row);
+  ++buffer->dirty;
 }
 
-void editorRowAppendString(struct editorConfig *E, erow *row, char *s,
-                           size_t len) {
+void bufferRowAppendString(struct buffer_t *buffer, frow *row, char *s, size_t len) {
   row->chars = realloc(row->chars, row->size + len + 1);
   memcpy(&row->chars[row->size], s, len);
   row->size += len;
   row->chars[row->size] = '\0';
-  editorUpdateRow(row);
-  ++E->dirty;
+  bufferUpdatfrow(row);
+  ++buffer->dirty;
 }
 
 /**
- * \fn editorRowDelChar(struct editorConfig *E, erow *erow, int at)
+ * \fn bufferRowDelChar(struct bufferConfig *E, frow *frow, int at)
  * \brief Delete the a char at the chosen position on the given row
  * \param at Index of the char to delete
  * \param row Row on operation is made */
-void editorRowDelchar(struct editorConfig *E, erow *row, int at) {
+void bufferRowDelchar(struct buffer_t *buffer, frow *row, int at) {
   if (at < 0 || at >= row->size) {
     return;
   }
   memmove(&row->chars[at], &row->chars[at + 1], row->size - at);
   --row->size;
-  editorUpdateRow(row);
-  ++E->dirty;
+  bufferUpdatfrow(row);
+  ++buffer->dirty;
 }

src/split_screen.c

@@ -0,0 +1,218 @@
+/**
+ * @file split_screen.c
+ * @brief Split screen implementation
+ */
+
+#include "../include/split_screen.h"
+#include "../include/buffer.h"
+#include "../include/editor_op.h"
+#include <stdlib.h>
+#include <string.h>
+
+extern struct editorConfig E;
+
+/**
+ * @brief Initializes split screen system with single fullscreen pane
+ */
+void splitScreenInit(void) {
+    E.layout.mode = SPLIT_NONE;
+    E.layout.num_panes = 1;
+    E.layout.active_pane = 0;
+    
+    E.layout.panes = malloc(sizeof(EditorPane) * 2);
+    
+    // Initialize single fullscreen pane
+    E.layout.panes[0].buffer_id = -1; // No buffer for now
+    E.layout.panes[0].start_row = 0;
+    E.layout.panes[0].start_col = 0;
+    E.layout.panes[0].height = E.screenrows - 2;  // Leave room for status bar
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].row_offset = 0;
+    E.layout.panes[0].col_offset = 0;
+    E.layout.panes[0].is_active = 1;
+}
+
+/**
+ * @brief Splits screen vertically (left-right)
+ * @param buffer_id_left Buffer ID for left pane
+ * @param buffer_id_right Buffer ID for right pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenVertical(int buffer_id_left, int buffer_id_right) {
+    // Verify both buffers exist
+    if (bufferFindById(buffer_id_left) == NULL ||
+        bufferFindById(buffer_id_right) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer IDs");
+        return -1;
+    }
+    
+    // Reallocate panes array
+    E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
+    E.layout.mode = SPLIT_VERTICAL;
+    E.layout.num_panes = 2;
+    E.layout.active_pane = 0;
+    
+    int half_width = E.screencols / 2;
+    int pane_height = E.screenrows - 2;  // Leave room for status bar
+    
+    // Left pane
+    E.layout.panes[0].buffer_id = buffer_id_left;
+    E.layout.panes[0].start_row = 0;
+    E.layout.panes[0].start_col = 0;
+    E.layout.panes[0].height = pane_height;
+    E.layout.panes[0].width = half_width;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].row_offset = 0;
+    E.layout.panes[0].col_offset = 0;
+    E.layout.panes[0].is_active = 1;
+    
+    // Right pane
+    E.layout.panes[1].buffer_id = buffer_id_right;
+    E.layout.panes[1].start_row = 0;
+    E.layout.panes[1].start_col = half_width;
+    E.layout.panes[1].height = pane_height;
+    E.layout.panes[1].width = E.screencols - half_width;
+    E.layout.panes[1].cursor_x = 0;
+    E.layout.panes[1].cursor_y = 0;
+    E.layout.panes[1].row_offset = 0;
+    E.layout.panes[1].col_offset = 0;
+    E.layout.panes[1].is_active = 0;
+    
+    editorSetStatusMessage("Vertical split: %d | %d", buffer_id_left, buffer_id_right);
+    return 0;
+}
+
+/**
+ * @brief Splits screen horizontally (top-bottom)
+ * @param buffer_id_top Buffer ID for top pane
+ * @param buffer_id_bottom Buffer ID for bottom pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom) {
+    // Verify both buffers exist
+    if (bufferFindById(buffer_id_top) == NULL ||
+        bufferFindById(buffer_id_bottom) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer IDs");
+        return -1;
+    }
+    
+    // Reallocate panes array
+    E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
+    E.layout.mode = SPLIT_HORIZONTAL;
+    E.layout.num_panes = 2;
+    E.layout.active_pane = 0;
+    
+    int half_height = (E.screenrows - 2) / 2;  // Account for status bar
+    
+    // Top pane
+    E.layout.panes[0].buffer_id = buffer_id_top;
+    E.layout.panes[0].start_row = 0;
+    E.layout.panes[0].start_col = 0;
+    E.layout.panes[0].height = half_height;
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].row_offset = 0;
+    E.layout.panes[0].col_offset = 0;
+    E.layout.panes[0].is_active = 1;
+    
+    // Bottom pane
+    E.layout.panes[1].buffer_id = buffer_id_bottom;
+    E.layout.panes[1].start_row = half_height;
+    E.layout.panes[1].start_col = 0;
+    E.layout.panes[1].height = E.screenrows - 2 - half_height;
+    E.layout.panes[1].width = E.screencols;
+    E.layout.panes[1].cursor_x = 0;
+    E.layout.panes[1].cursor_y = 0;
+    E.layout.panes[1].row_offset = 0;
+    E.layout.panes[1].col_offset = 0;
+    E.layout.panes[1].is_active = 0;
+    
+    editorSetStatusMessage("Horizontal split: %d / %d", buffer_id_top, buffer_id_bottom);
+    return 0;
+}
+
+/**
+ * @brief Returns to single buffer fullscreen
+ */
+void splitScreenUnify(void) {
+    E.layout.mode = SPLIT_NONE;
+    E.layout.num_panes = 1;
+    E.layout.active_pane = 0;
+    
+    E.layout.panes[0].start_row = 0;
+    E.layout.panes[0].start_col = 0;
+    E.layout.panes[0].height = E.screenrows - 2;
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].is_active = 1;
+    
+    editorSetStatusMessage("Unified view");
+}
+
+/**
+ * @brief Switches active pane (focus moves between splits)
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSwitchPane(void) {
+    if (E.layout.num_panes < 2) {
+        editorSetStatusMessage("No split to switch");
+        return -1;
+    }
+    
+    // Deactivate current pane
+    E.layout.panes[E.layout.active_pane].is_active = 0;
+    
+    // Move to next pane
+    E.layout.active_pane = (E.layout.active_pane + 1) % E.layout.num_panes;
+    
+    // Activate new pane
+    E.layout.panes[E.layout.active_pane].is_active = 1;
+    
+    editorSetStatusMessage("Switched to pane %d (buffer %d)", 
+                          E.layout.active_pane,
+                          E.layout.panes[E.layout.active_pane].buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Updates the active pane's buffer
+ * @param buffer_id New buffer ID for active pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSetPaneBuffer(int buffer_id) {
+    if (bufferFindById(buffer_id) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer ID");
+        return -1;
+    }
+    
+    EditorPane *active = &E.layout.panes[E.layout.active_pane];
+    active->buffer_id = buffer_id;
+    active->cursor_x = 0;
+    active->cursor_y = 0;
+    active->row_offset = 0;
+    active->col_offset = 0;
+    
+    editorSetStatusMessage("Pane %d now showing buffer %d", 
+                          E.layout.active_pane, buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Gets current screen layout
+ * @return Pointer to current ScreenLayout
+ */
+ScreenLayout *splitScreenGetLayout(void) {
+    return &E.layout;
+}
+
+/**
+ * @brief Gets active pane
+ * @return Pointer to active EditorPane
+ */
+EditorPane *splitScreenGetActivePane(void) {
+    if (E.layout.num_panes == 0) return NULL;
+    return &E.layout.panes[E.layout.active_pane];
+}

src/syntax_highlighter.c

@@ -0,0 +1,197 @@
+#include "../include/syntax_highlighter.h"
+#include "../include/data.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+extern struct editorConfig E;
+
+const char *c_keywords[] = {
+    "if",     "else",     "while",    "for",     "do",       "switch",
+    "case",   "break",    "#include", "#define", "continue", "return",
+    "goto",   "struct",   "union",    "enum",    "typedef",  "static",
+    "extern", "const",    "volatile", "sizeof",  "auto",     "register",
+    "inline", "restrict", NULL};
+
+// C types
+const char *c_types[] = {"int",    "char", "float", "double",
+                         "void",   "long", "short", "unsigned",
+                         "signed", "bool", NULL};
+
+// Check if character is alphanumeric or underscore
+int is_word_char(char c) {
+  return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
+         (c >= '0' && c <= '9') || c == '_' || c == '#';
+}
+
+// Check if string is a keyword
+int is_keyword(const char *word) {
+  for (int i = 0; c_keywords[i] != NULL; i++) {
+    if (strcmp(word, c_keywords[i]) == 0)
+      return 1;
+  }
+  return 0;
+}
+
+// Check if string is a type
+int is_type(const char *word) {
+  for (int i = 0; c_types[i] != NULL; i++) {
+    if (strcmp(word, c_types[i]) == 0)
+      return 1;
+  }
+  return 0;
+}
+
+// Get color code for token type
+const char *get_color(TokenType type) {
+  switch (type) {
+  case TOKEN_KEYWORD:
+    return E.theme.COLOR_KEYWORD;
+  case TOKEN_TYPE:
+    return E.theme.COLOR_TYPE;
+  case TOKEN_STRING:
+    return E.theme.COLOR_STRING;
+  case TOKEN_COMMENT:
+    return E.theme.COLOR_COMMENT;
+  case TOKEN_NUMBER:
+    return E.theme.COLOR_NUMBER;
+  default:
+    return E.theme.COLOR_DEFAULT;
+  }
+}
+
+int comment_section = 0;
+
+// Highlight a line of C code and return the highlighted string
+// Returns a newly allocated string that must be freed by the caller
+char *highlight_line(const char *line, int *length) {
+  char *result = malloc(1024); // Allocate space for result
+  int result_pos = 0;
+  int i = 0;
+
+  while (line[i] != '\0' && line[i] != '\n') {
+    // Skip whitespace
+    if (line[i] == ' ' || line[i] == '\t') {
+      result[result_pos++] = line[i++];
+      continue;
+    }
+    
+    if (comment_section) {
+      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      while (line[i] != '\0' && line[i] != '\n') {
+        
+    if (line[i] == '*' && line[i + 1] == '/') {
+      comment_section = 0;
+    }
+
+        result[result_pos++] = line[i++];
+      }
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle line comments
+    if (line[i] == '/' && line[i + 1] == '/') {
+      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      while (line[i] != '\0' && line[i] != '\n') {
+        result[result_pos++] = line[i++];
+      }
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle block comments
+    if ((line[i] == '/' && line[i + 1] == '*')) {
+      comment_section = 1;
+      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      result[result_pos++] = line[i++];
+      result[result_pos++] = line[i++];
+      while (line[i] != '\0') {
+        if (line[i] == '*' && line[i + 1] == '/') {
+          result[result_pos++] = line[i++];
+          result[result_pos++] = line[i++];
+          break;
+        }
+        result[result_pos++] = line[i++];
+      }
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle strings
+    if (line[i] == '"') {
+      result_pos += sprintf(&result[result_pos], "%s\"", E.theme.COLOR_STRING);
+      i++;
+      while (line[i] != '\0' && line[i] != '"') {
+        if (line[i] == '\\') {
+          result[result_pos++] = line[i++];
+          result[result_pos++] = line[i++];
+        } else {
+          result[result_pos++] = line[i++];
+        }
+      }
+      if (line[i] == '"')
+        result[result_pos++] = line[i++];
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle character literals
+    if (line[i] == '\'') {
+      result_pos += sprintf(&result[result_pos], "%s'", E.theme.COLOR_STRING);
+      i++;
+      while (line[i] != '\0' && line[i] != '\'') {
+        if (line[i] == '\\') {
+          result[result_pos++] = line[i++];
+          result[result_pos++] = line[i++];
+        } else {
+          result[result_pos++] = line[i++];
+        }
+      }
+      if (line[i] == '\'')
+        result[result_pos++] = line[i++];
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle numbers
+    if (line[i] >= '0' && line[i] <= '9') {
+      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_NUMBER);
+      while (is_word_char(line[i]) || line[i] == '.') {
+        result[result_pos++] = line[i++];
+      }
+      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle identifiers and keywords
+    if (is_word_char(line[i])) {
+      int start = i;
+      while (is_word_char(line[i]))
+        i++;
+
+      char word[256];
+      strncpy(word, &line[start], i - start);
+      word[i - start] = '\0';
+
+      TokenType type = TOKEN_DEFAULT;
+      if (is_keyword(word))
+        type = TOKEN_KEYWORD;
+      else if (is_type(word))
+        type = TOKEN_TYPE;
+
+      result_pos += sprintf(&result[result_pos], "%s%s%s", get_color(type),
+                            word, COLOR_RESET);
+      continue;
+    }
+
+    // Handle operators and other characters
+    result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_DEFAULT);
+    result[result_pos++] = line[i++];
+    result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+  }
+
+  result[result_pos] = '\0';
+  *length = result_pos + 1;
+  return result;
+}

src/terminal.c

@@ -1,24 +1,28 @@
 #include "../include/terminal.h"
+#include "../include/data.h"
+
+#include <stdio.h>
 
 void die(const char *s) {
   write(STDOUT_FILENO, "\x1b[2J", 4);
   write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
+  lisp_shutdown(E.ctx);
   perror(s);
   exit(1);
 }
 
-void disableRawMode(struct editorConfig *E) {
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E->orig_termios) == -1) {
+void disableRawMode() {
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1) {
     die("tcsetattr");
   }
 }
 
-void enableRawMode(struct editorConfig *E) {
-  if (tcgetattr(STDIN_FILENO, &E->orig_termios) == -1) {
+void enableRawMode() {
+  if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) {
     die("tcgetattr");
   }
 
-  struct termios raw = E->orig_termios;
+  struct termios raw = E.orig_termios;
   raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
   raw.c_oflag &= ~(OPOST);
   raw.c_cflag |= (CS8);