diff --git a/include/config_tools.h b/include/config_tools.h
index be87dba..be22c8a 100644
--- a/include/config_tools.h
+++ b/include/config_tools.h
@@ -5,30 +5,24 @@
 #include "parser.h"
 #include <stdio.h>
 
-config_t *config_create(void);
-void free_node(node_t *node);
-void config_destroy(config_t *config);
-int handle_map_key(config_t *config, node_t **args, int arg_count);
-int handle_define(config_t *config, node_t **args, int arg_count);
-int execute_function_call(config_t *config, node_t *call);
-int config_parse_string(config_t *config, const char *input);
-int config_parse_file(config_t *config, const char *filename);
+void config_create(void);
+void init_builtin_functions(void);
 
-const char *config_get_key_mapping(config_t *config, const char *key_combo);
-node_t *find_variable(config_t *config, const char *name);
+int handle_map_key(node_t **args, int arg_count);
+int handle_define(node_t **args, int arg_count);
+int handle_function(node_t **args, int arg_count);
 
-const char *config_get_string(config_t *config, const char *path,
-                              const char *default_value);
-int config_get_int(config_t *config, const char *path, int default_value);
-double config_get_double(config_t *config, const char *path,
-                         double default_value);
-bool config_get_bool(config_t *config, const char *path, bool default_value);
-void config_print_all(config_t *config);
+int execute_function_call(node_t *call);
+int config_parse_string(const char *input);
+int config_parse_file(const char *filename);
 
-static struct {
-  const char *name;
-  int (*handler)(config_t *config, node_t **args, int arg_count);
-} builtin_functions[] = {
-    {"map-key", handle_map_key}, {"define", handle_define}, {NULL, NULL}};
+const char *config_get_key_mapping(const char *key_combo);
+node_t *find_variable(const char *name);
+
+const char *config_get_string(const char *path, const char *default_value);
+int config_get_int(const char *path, int default_value);
+double config_get_double(const char *path, double default_value);
+bool config_get_bool(const char *path, bool default_value);
+void config_print_all(void);
 
 #endif
diff --git a/include/data.h b/include/data.h
index fccb8c4..8c8270e 100644
--- a/include/data.h
+++ b/include/data.h
@@ -1,12 +1,7 @@
 #ifndef DATA_H_PARSER
 #define DATA_H_PARSER
 
-#include "define.h"
-#include <ctype.h>
 #include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 
 // Token types for lexical analysis
 
@@ -26,7 +21,7 @@ typedef enum {
 
 typedef struct {
   token_type_t type;
-  char value[MAX_TOKEN_LENGTH];
+  char *value;
   int line;
   int column;
 } token_t;
@@ -37,23 +32,28 @@ typedef enum {
   NODE_STRING,
   NODE_NUMBER,
   NODE_BOOLEAN,
-  NODE_FUNCTION_REF, // %function-name
-  NODE_FUNCTION_CALL // ,function-name()
+  NODE_FUNCTION_REF,  // %function-name
+  NODE_FUNCTION_CALL, // ,function-name()
+  NODE_LIST
 } node_type_t;
 
 typedef struct node {
   node_type_t type;
   union {
-    char symbol[MAX_SYMBOL_LENGTH];
-    char string[MAX_STRING_LENGTH];
+    char *symbol;
+    char *string;
     double number;
     bool boolean;
-    char function_ref[MAX_SYMBOL_LENGTH];
+    char *function_ref;
     struct {
-      char function_name[MAX_SYMBOL_LENGTH];
-      struct node *args[MAX_ARGS];
+      char *function_name;
+      struct node **args;
       int arg_count;
     } call;
+    struct {
+      struct node **children;
+      int child_count;
+    } list;
   } data;
 } node_t;
 
@@ -79,22 +79,73 @@ typedef struct config_var {
   struct config_var *next;
 } config_var_t;
 
-typedef struct {
+typedef struct config {
   key_mapping_t *key_mappings;
   config_var_t *variables;
 } config_t;
 
+// Execution context for function calls
+typedef struct exec_context {
+  struct {
+    char **names;
+    node_t **values;
+    int count;
+  } local_vars;
+} exec_context_t;
+
+typedef void (*command_func_t)(void);
+
+typedef enum { FUNC_BUILTIN, FUNC_USER_DEFINED, FUNC_REGISTRY } function_type_t;
+
+typedef struct unified_function {
+  char *name;
+  function_type_t type;
+  union {
+    // For built-in functions
+    struct {
+      int (*handler)(node_t **args, int arg_count);
+      bool eval_args; // Whether to evaluate arguments before calling
+    } builtin;
+
+    // For user-defined functions
+    struct {
+      char **parameters;
+      int param_count;
+      node_t *body;
+    } user_defined;
+
+    // For registry functions
+    struct {
+      command_func_t func;
+    } registry;
+  } data;
+
+  struct unified_function *next;
+} unified_function_t;
+
 void advance_char(lexer_t *lexer);
 void skip_whitespace(lexer_t *lexer);
 void skip_comment(lexer_t *lexer);
-node_t *create_node(node_type_t type);
-node_t *create_symbol_node(const char *symbol);
-node_t *create_string_node(const char *string);
-node_t *create_number_node(double number);
-node_t *create_boolean_node(bool value);
-node_t *create_function_ref_node(const char *function_name);
-node_t *create_function_call_node(const char *function_name);
 
 void add_arg_to_call(node_t *call, node_t *args);
+void add_to_list(node_t *node, node_t *element);
 
 #endif
+
+#ifdef GLOBAL_CONFIG
+
+unified_function_t *unified_functions = NULL;
+int registry_count;
+config_var_t variable_registry[256];
+int var_registry_count;
+
+config_t config;
+#else
+
+extern unified_function_t *unified_functions;
+extern int registry_count;
+extern config_var_t variable_registry[256];
+extern int var_registry_count;
+
+extern config_t config;
+#endif
diff --git a/include/function.h b/include/function.h
new file mode 100644
index 0000000..739f2f1
--- /dev/null
+++ b/include/function.h
@@ -0,0 +1,24 @@
+#ifndef FUNCTION_H_
+#define FUNCTION_H_
+
+#include "data.h"
+
+int register_builtin_function(const char *name, int (*handler)(node_t **, int),
+                              bool eval_args);
+int register_user_function(const char *name, char **parameters, int param_count,
+                           node_t *body);
+int register_registry_function(const char *name, command_func_t func);
+
+int register_function(const char *name, command_func_t func);
+
+unified_function_t *find_unified_function(const char *name);
+
+node_t *execute_unified_function(exec_context_t *ctx, const char *name,
+                                 node_t **args, int arg_count);
+
+command_func_t find_function(const char *name);
+int execute_command(const char *name);
+
+node_t *execute_function_call_in_context(exec_context_t *ctx, node_t *call);
+
+#endif
diff --git a/include/lexer.h b/include/lexer.h
index 081a23b..ba7a3ef 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -2,6 +2,8 @@
 #define LEXER_H_
 
 #include "data.h"
+#include <ctype.h>
+#include <string.h>
 
 token_t next_token(lexer_t *lexer);
 
diff --git a/include/node.h b/include/node.h
new file mode 100644
index 0000000..68027fd
--- /dev/null
+++ b/include/node.h
@@ -0,0 +1,20 @@
+#ifndef NODE_T_
+#define NODE_T_
+
+#include "data.h"
+
+node_t *create_node(node_type_t type);
+node_t *create_symbol_node(const char *symbol);
+node_t *create_string_node(const char *string);
+node_t *create_number_node(double number);
+node_t *create_boolean_node(bool value);
+node_t *create_list_node(void);
+node_t *create_function_ref_node(const char *function_name);
+node_t *create_function_call_node(const char *function_name);
+
+void free_node(node_t *node);
+node_t *copy_node(node_t *src);
+
+node_t *evaluate_node(exec_context_t *ctx, node_t *node);
+
+#endif
diff --git a/include/parser.h b/include/parser.h
index 6029a10..d6dce27 100644
--- a/include/parser.h
+++ b/include/parser.h
@@ -2,10 +2,10 @@
 #define PARSER_H_
 
 #include "data.h"
-#include "lexer.h"
 
 node_t *parse_atom(lexer_t *lexer, token_t *token);
 node_t *parse_function_call(lexer_t *lexer, const char *function_name);
 node_t *parse_statement(lexer_t *lexer);
+node_t *parse_expression(lexer_t *lexer, token_t *token);
 
 #endif
diff --git a/init.bl b/init.bl
index 741a275..6f20209 100644
--- a/init.bl
+++ b/init.bl
@@ -8,5 +8,10 @@
 ,map-key("CTRL-w s h" %window-split-horizontal)
 ,map-key("CTRL-w s v" %window-split-vertical)
 
+,fun(saveQuit () (
+    ,editorSave
+    ,editorQuit
+))
+
 ,define(theme "dark")
 ,define(auto-save true)
diff --git a/main.c b/main.c
index acf8bdd..365f9bf 100644
--- a/main.c
+++ b/main.c
@@ -1,38 +1,34 @@
 
-#include "src/data.h"
-#include "src/config_tools.h"
+#define GLOBAL_EDITOR
 
-int main() {
+#include "include/config_tools.h"
+#include "include/data.h"
+
+int main(void) {
   // Parse the configuration
-  config_t *config = config_create();
+  config_create();
   char *config_file = "init.bl";
-  if (!config) {
-    fprintf(stderr, "Error: Failed to create config structure\n");
-    return 1;
-  }
 
-  if (config_parse_file(config, config_file) != 0) {
+  if (config_parse_file(config_file) != 0) {
     fprintf(stderr, "Error: Failed to parse config file\n");
-    config_destroy(config);
     return 1;
   }
 
   printf("Successfully parsed Lisp config file: %s\n\n", config_file);
 
   // Print all entries
-  config_print_all(config);
+  config_print_all();
   printf("\n");
 
   // Demonstrate usage
   printf("Example usage:\n");
-  printf("CTRL-s maps to: %s\n", config_get_key_mapping(config, "CTRL-s"));
-  printf("CTRL-f o maps to: %s\n", config_get_key_mapping(config, "CTRL-f o"));
-  printf("Window width: %d\n", config_get_int(config, "window-width", 1024));
-  printf("Theme: %s\n", config_get_string(config, "theme", "light"));
+  printf("CTRL-s maps to: %s\n", config_get_key_mapping("CTRL-s"));
+  printf("CTRL-f o maps to: %s\n", config_get_key_mapping("CTRL-f o"));
+  printf("Window width: %d\n", config_get_int("window-width", 1024));
+  printf("Theme: %s\n", config_get_string("theme", "light"));
   printf("Auto-save: %s\n",
-         config_get_bool(config, "auto-save", false) ? "enabled" : "disabled");
-  printf("Font size: %d\n", config_get_int(config, "font-size", 12));
+         config_get_bool("auto-save", false) ? "enabled" : "disabled");
+  printf("Font size: %d\n", config_get_int("font-size", 12));
 
-  config_destroy(config);
   return 0;
 }
diff --git a/src/config_tools.c b/src/config_tools.c
index 1098633..baedad0 100644
--- a/src/config_tools.c
+++ b/src/config_tools.c
@@ -1,62 +1,29 @@
+
 #include "../include/config_tools.h"
+#include "../include/function.h"
+#include "../include/node.h"
+#define GLOBAL_CONFIG
 #include "../include/data.h"
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
-config_t *config_create(void) {
+void config_create(void) {
   /*
    * @brief Initialize config structure
    */
-  config_t *config = malloc(sizeof(config_t));
-  if (config) {
-    config->key_mappings = NULL;
-    config->variables = NULL;
-  }
-  return config;
+  config.key_mappings = NULL;
+  config.variables = NULL;
 }
 
-void free_node(node_t *node) {
-  int i;
-  if (!node)
-    return;
-
-  if (node->type == NODE_FUNCTION_CALL) {
-    for (i = 0; i < node->data.call.arg_count; i++) {
-      free_node(node->data.call.args[i]);
-    }
-    // free(node->data.call.args);
-  }
-
-  free(node);
-}
-
-void config_destroy(config_t *config) {
-  if (!config)
-    return;
-
-  key_mapping_t *mapping = config->key_mappings;
-  while (mapping) {
-    key_mapping_t *next = mapping->next;
-    free(mapping->key_combo);
-    free(mapping->function_name);
-    free(mapping);
-    mapping = next;
-  }
-
-  // Free variables
-  config_var_t *var = config->variables;
-  while (var) {
-    config_var_t *next = var->next;
-    free(var->name);
-    free_node(var->value);
-    free(var);
-    var = next;
-  }
-
-  free(config);
+void init_builtin_functions(void) {
+  register_builtin_function("map-key", handle_map_key, true);
+  register_builtin_function("define", handle_define, false); // Don't eval args
+  register_builtin_function("func", handle_function, false); // Don't eval args
 }
 
 // Built-in function handlers
-int handle_map_key(config_t *config, node_t **args, int arg_count) {
+int handle_map_key(node_t **args, int arg_count) {
   if (arg_count != 2 || args[0]->type != NODE_STRING ||
       args[1]->type != NODE_FUNCTION_REF) {
     fprintf(stderr, "Error: map-key requires (key_combo, function_ref)\n");
@@ -69,48 +36,134 @@ int handle_map_key(config_t *config, node_t **args, int arg_count) {
 
   mapping->key_combo = strdup(args[0]->data.string);
   mapping->function_name = strdup(args[1]->data.function_ref);
-  mapping->next = config->key_mappings;
-  config->key_mappings = mapping;
+  mapping->next = config.key_mappings;
+  config.key_mappings = mapping;
 
   return 0;
 }
 
-int handle_define(config_t *config, node_t **args, int arg_count) {
-  if (arg_count != 2 || args[0]->type != NODE_SYMBOL) {
-    fprintf(stderr, "Error: define requires (variable_name, value)\n");
+int handle_define(node_t **args, int arg_count) {
+
+  if (arg_count != 2) {
+    fprintf(stderr, "Error: define requires exactly 2 arguments, got %d\n",
+            arg_count);
+    return -1;
+  }
+
+  if (args[0]->type != NODE_SYMBOL) {
+    fprintf(
+        stderr,
+        "Error: define requires first argument to be a symbol, got type %d\n",
+        args[0]->type);
     return -1;
   }
 
   config_var_t *var = malloc(sizeof(config_var_t));
-  if (!var)
+  if (!var) {
+    fprintf(stderr, "Error: Failed to allocate memory for variable\n");
     return -1;
+  }
 
   var->name = strdup(args[0]->data.symbol);
-  var->value = args[1]; // Transfer ownership
-  var->next = config->variables;
-  config->variables = var;
+  if (!var->name) {
+    free(var);
+    fprintf(stderr, "Error: Failed to allocate memory for variable name\n");
+    return -1;
+  }
+
+  var->value = copy_node(args[1]);
+  if (!var->value) {
+    free(var->name);
+    free(var);
+    fprintf(stderr, "Error: Failed to copy variable value\n");
+    return -1;
+  }
+
+  var->next = config.variables;
+  config.variables = var;
+
+  // Verify it was stored
+  config_var_t *check = config.variables;
+  while (check) {
+    check = check->next;
+  }
 
   return 0;
 }
 
-int execute_function_call(config_t *config, node_t *call) {
-  if (call->type != NODE_FUNCTION_CALL)
+int handle_function(node_t **args, int arg_count) {
+  if (arg_count != 3) {
+    fprintf(stderr, "Error: func requires exactly 3 arguments, got %d\n",
+            arg_count);
     return -1;
+  }
 
-  // Look for built-in function
-  for (int i = 0; builtin_functions[i].name; i++) {
-    if (strcmp(call->data.call.function_name, builtin_functions[i].name) == 0) {
-      return builtin_functions[i].handler(config, call->data.call.args,
-                                          call->data.call.arg_count);
+  if (args[0]->type != NODE_SYMBOL) {
+    fprintf(
+        stderr,
+        "Error: func requires first argument to be a symbol (function name)\n");
+    return -1;
+  }
+
+  if (args[1]->type != NODE_LIST) {
+    fprintf(stderr,
+            "Error: func requires second argument to be a list (parameters)\n");
+    return -1;
+  }
+
+  // Prepare parameters
+  node_t *param_list = args[1];
+  int param_count = param_list->data.list.child_count;
+  char **parameters = NULL;
+
+  if (param_count > 0) {
+    parameters = malloc(sizeof(char *) * param_count);
+    if (!parameters)
+      return -1;
+
+    for (int i = 0; i < param_count; i++) {
+      if (param_list->data.list.children[i]->type != NODE_SYMBOL) {
+        fprintf(stderr, "Error: Function parameters must be symbols\n");
+        for (int j = 0; j < i; j++) {
+          free(parameters[j]);
+        }
+        free(parameters);
+        return -1;
+      }
+      parameters[i] = strdup(param_list->data.list.children[i]->data.symbol);
     }
   }
 
-  fprintf(stderr, "Error: Unknown function '%s'\n",
-          call->data.call.function_name);
+  // Prepare body
+  node_t *body = args[2];
+  if (body->type != NODE_LIST) {
+    node_t *wrapper = create_list_node();
+    add_to_list(wrapper, copy_node(body));
+    body = wrapper;
+  } else {
+    body = copy_node(body);
+  }
+
+  // Register the function
+  return register_user_function(args[0]->data.symbol, parameters, param_count,
+                                body);
+}
+
+int execute_function_call(node_t *call) {
+  exec_context_t ctx = {0};
+  ctx.local_vars.names = NULL;
+  ctx.local_vars.values = NULL;
+  ctx.local_vars.count = 0;
+
+  node_t *result = execute_function_call_in_context(&ctx, call);
+  if (result) {
+    free_node(result);
+    return 0;
+  }
   return -1;
 }
 
-int config_parse_string(config_t *config, const char *input) {
+int config_parse_string(const char *input) {
   lexer_t lexer = {0};
   lexer.input = input;
   lexer.pos = 0;
@@ -119,7 +172,6 @@ int config_parse_string(config_t *config, const char *input) {
   lexer.current_char = input[0];
 
   while (lexer.current_char != '\0') {
-    printf("%c", lexer.current_char);
     skip_whitespace(&lexer);
     skip_comment(&lexer);
     skip_whitespace(&lexer);
@@ -133,12 +185,13 @@ int config_parse_string(config_t *config, const char *input) {
 
     node_t *stmt = parse_statement(&lexer);
     if (stmt) {
-      if (execute_function_call(config, stmt) != 0) {
+      if (execute_function_call(stmt) != 0) {
         fprintf(stderr, "Error executing statement at line %d\n", lexer.line);
       }
       if (stmt->type != NODE_FUNCTION_CALL ||
-          strcmp(stmt->data.call.function_name, "define") != 0) {
-        free_node(stmt); // Don't free if ownership was transferred to define
+          (strcmp(stmt->data.call.function_name, "define") != 0 &&
+           strcmp(stmt->data.call.function_name, "func") != 0)) {
+        free_node(stmt); // Don't free if ownership was transferred
       }
     }
 
@@ -151,7 +204,7 @@ int config_parse_string(config_t *config, const char *input) {
   return 0;
 }
 
-int config_parse_file(config_t *config, const char *filename) {
+int config_parse_file(const char *filename) {
   FILE *file = fopen(filename, "r");
   long file_size = 0;
   char *content = NULL;
@@ -175,7 +228,7 @@ int config_parse_file(config_t *config, const char *filename) {
   content[file_size] = '\0';
   fclose(file);
 
-  result = config_parse_string(config, content);
+  result = config_parse_string(content);
   free(content);
 
   return result;
@@ -183,8 +236,8 @@ int config_parse_file(config_t *config, const char *filename) {
 
 // Getter functions
 
-const char *config_get_key_mapping(config_t *config, const char *key_combo) {
-  key_mapping_t *mapping = config->key_mappings;
+const char *config_get_key_mapping(const char *key_combo) {
+  key_mapping_t *mapping = config.key_mappings;
   while (mapping) {
     if (strcmp(mapping->key_combo, key_combo) == 0) {
       return mapping->function_name;
@@ -194,8 +247,8 @@ const char *config_get_key_mapping(config_t *config, const char *key_combo) {
   return NULL;
 }
 
-node_t *find_variable(config_t *config, const char *name) {
-  config_var_t *var = config->variables;
+node_t *find_variable(const char *name) {
+  config_var_t *var = config.variables;
   while (var) {
     if (strcmp(var->name, name) == 0) {
       return var->value;
@@ -205,58 +258,56 @@ node_t *find_variable(config_t *config, const char *name) {
   return NULL;
 }
 
-const char *config_get_string(config_t *config, const char *path,
-                              const char *default_value) {
-  node_t *node = find_variable(config, path);
+const char *config_get_string(const char *path, const char *default_value) {
+  node_t *node = find_variable(path);
   if (node && node->type == NODE_STRING) {
     return node->data.string;
   }
   return default_value;
 }
 
-int config_get_int(config_t *config, const char *path, int default_value) {
-  node_t *node = find_variable(config, path);
+int config_get_int(const char *path, int default_value) {
+  node_t *node = find_variable(path);
   if (node && node->type == NODE_NUMBER) {
     return (int)node->data.number;
   }
   return default_value;
 }
 
-double config_get_double(config_t *config, const char *path,
-                         double default_value) {
-  node_t *node = find_variable(config, path);
+double config_get_double(const char *path, double default_value) {
+  node_t *node = find_variable(path);
   if (node && node->type == NODE_NUMBER) {
     return node->data.number;
   }
   return default_value;
 }
 
-bool config_get_bool(config_t *config, const char *path, bool default_value) {
-  node_t *node = find_variable(config, path);
+bool config_get_bool(const char *path, bool default_value) {
+  node_t *node = find_variable(path);
   if (node && node->type == NODE_BOOLEAN) {
     return node->data.boolean;
   }
   return default_value;
 }
 
-void config_print_all(config_t *config) {
+void config_print_all(void) {
   printf("Key Mappings:\n");
-  printf("%-20s -> %s\n", "Key Combination", "Function");
-  printf("%-20s    %s\n", "---------------", "--------");
+  printf("%-20s -> %s\n", "Key Combination", "Function\n");
+  printf("%-20s    %s\n", "---------------", "--------\n");
 
-  key_mapping_t *mapping = config->key_mappings;
+  key_mapping_t *mapping = config.key_mappings;
   while (mapping) {
     printf("%-20s -> %s\n", mapping->key_combo, mapping->function_name);
     mapping = mapping->next;
   }
 
   printf("\nVariables:\n");
-  printf("%-20s = %s\n", "Name", "Value");
-  printf("%-20s   %s\n", "----", "-----");
+  printf("%-20s = %s\n", "Name", "Value\n");
+  printf("%-20s   %s\n", "----", "-----\n");
 
-  config_var_t *var = config->variables;
+  config_var_t *var = config.variables;
   while (var) {
-    printf("%-20s = ", var->name);
+    printf("%-20s = \n", var->name);
 
     switch (var->value->type) {
     case NODE_STRING:
diff --git a/src/data.c b/src/data.c
index 3e32e3a..5814076 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1,5 +1,8 @@
 #include "../include/data.h"
 #include "../include/define.h"
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 void advance_char(lexer_t *lexer) {
@@ -27,74 +30,63 @@ void skip_comment(lexer_t *lexer) {
   }
 }
 
-// Node creation functions
-node_t *create_node(node_type_t type) {
+node_t *create_list_node(void) {
   node_t *node = malloc(sizeof(node_t));
-  if (!node)
+  if (!node) {
     return NULL;
-
-  memset(node, 0, sizeof(node_t));
-  node->type = type;
-  return node;
-}
-
-node_t *create_symbol_node(const char *symbol) {
-  node_t *node = create_node(NODE_SYMBOL);
-  if (node) {
-    strncpy(node->data.symbol, symbol, MAX_SYMBOL_LENGTH - 1);
-    node->data.symbol[MAX_SYMBOL_LENGTH - 1] = '\0';
   }
-  return node;
-}
 
-node_t *create_string_node(const char *string) {
-  node_t *node = create_node(NODE_STRING);
-  if (node) {
-    strncpy(node->data.string, string, MAX_STRING_LENGTH - 1);
-    node->data.string[MAX_STRING_LENGTH - 1] = '\0';
-  }
-  return node;
-}
+  node->type = NODE_LIST;
+  node->data.list.child_count = 0;
+  node->data.list.children = NULL;
 
-node_t *create_number_node(double number) {
-  node_t *node = create_node(NODE_NUMBER);
-  if (node) {
-    node->data.number = number;
-  }
-  return node;
-}
-
-node_t *create_boolean_node(bool value) {
-  node_t *node = create_node(NODE_BOOLEAN);
-  if (node) {
-    node->data.boolean = value;
-  }
-  return node;
-}
-
-node_t *create_function_ref_node(const char *function_name) {
-  node_t *node = create_node(NODE_FUNCTION_REF);
-  if (node) {
-    strncpy(node->data.function_ref, function_name, MAX_SYMBOL_LENGTH - 1);
-    node->data.function_ref[MAX_SYMBOL_LENGTH - 1] = '\0';
-  }
-  return node;
-}
-
-node_t *create_function_call_node(const char *function_name) {
-  node_t *node = create_node(NODE_FUNCTION_CALL);
-  if (node) {
-    strncpy(node->data.call.function_name, function_name,
-            MAX_SYMBOL_LENGTH - 1);
-    node->data.call.function_name[MAX_SYMBOL_LENGTH - 1] = '\0';
-    node->data.call.arg_count = 0;
-  }
   return node;
 }
 
 void add_arg_to_call(node_t *call, node_t *arg) {
   if (call->type == NODE_FUNCTION_CALL &&
       call->data.call.arg_count < MAX_ARGS) {
+    call->data.call.args =
+        (node_t **)realloc(call->data.call.args,
+                           (call->data.call.arg_count + 1) * sizeof(node_t *));
     call->data.call.args[call->data.call.arg_count++] = arg;
   }
 }
+
+void add_to_list(node_t *list, node_t *element) {
+  node_t **new_children = NULL;
+  if (!list || !element) {
+    return;
+  }
+
+  // Ensure this is actually a list node
+  if (list->type != NODE_LIST) {
+    return;
+  }
+
+  // If this is the first element
+  if (list->data.list.children == NULL) {
+
+    fprintf(stderr, "DEBUG : child number 0 added\n");
+    list->data.list.children = malloc(sizeof(node_t *));
+    if (!list->data.list.children) {
+      return; // Memory allocation failed
+    }
+    list->data.list.children[0] = element;
+    list->data.list.child_count = 1;
+    return;
+  }
+
+  // Reallocate to add new element
+  new_children = realloc(list->data.list.children,
+                         sizeof(node_t *) * (list->data.list.child_count + 1));
+  if (!new_children) {
+    return; // Memory allocation failed
+  }
+
+  list->data.list.children = new_children;
+  list->data.list.children[list->data.list.child_count] = element;
+  list->data.list.child_count++;
+  fprintf(stderr, "DEBUG : child number %d added\n",
+          list->data.list.child_count);
+}
diff --git a/src/function.c b/src/function.c
new file mode 100644
index 0000000..e57eac7
--- /dev/null
+++ b/src/function.c
@@ -0,0 +1,215 @@
+#include "../include/function.h"
+#include "../include/data.h"
+#include "../include/node.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int register_builtin_function(const char *name,
+                              int (*handler)(node_t **args, int arg_count),
+                              bool eval_args) {
+  unified_function_t *func = malloc(sizeof(unified_function_t));
+  if (!func)
+    return -1;
+
+  func->name = strdup(name);
+  func->type = FUNC_BUILTIN;
+  func->data.builtin.handler = handler;
+  func->data.builtin.eval_args = eval_args;
+  func->next = unified_functions;
+  unified_functions = func;
+  fprintf(stderr, "%s succefully added\n", name);
+
+  return 0;
+}
+
+int register_user_function(const char *name, char **parameters, int param_count,
+                           node_t *body) {
+  unified_function_t *func = malloc(sizeof(unified_function_t));
+  if (!func)
+    return -1;
+
+  func->name = strdup(name);
+  func->type = FUNC_USER_DEFINED;
+  func->data.user_defined.parameters = parameters;
+  func->data.user_defined.param_count = param_count;
+  func->data.user_defined.body = body;
+  func->next = unified_functions;
+  unified_functions = func;
+
+  return 0;
+}
+
+int register_registry_function(const char *name, command_func_t c_func) {
+  unified_function_t *func = malloc(sizeof(unified_function_t));
+  if (!func)
+    return -1;
+
+  func->name = strdup(name);
+  func->type = FUNC_REGISTRY;
+  func->data.registry.func = c_func;
+  func->next = unified_functions;
+  unified_functions = func;
+  fprintf(stderr, "DEBIG : %s added\n", name);
+
+  return 0;
+}
+
+int register_function(const char *name, command_func_t func) {
+  return register_registry_function(name, func);
+}
+
+unified_function_t *find_unified_function(const char *name) {
+  unified_function_t *func = unified_functions;
+  while (func) {
+    // fprintf(stderr, "%s\n", func->name);
+    if (strcmp(func->name, name) == 0) {
+      return func;
+    }
+    func = func->next;
+  }
+  return NULL;
+}
+
+node_t *execute_unified_function(exec_context_t *ctx, const char *name,
+                                 node_t **args, int arg_count) {
+  unified_function_t *func = find_unified_function(name);
+  if (!func) {
+    fprintf(stderr, "Error: Unknown function '%s'\n", name);
+    return NULL;
+  }
+
+  switch (func->type) {
+  case FUNC_BUILTIN: {
+    node_t **eval_args = args;
+
+    // Evaluate arguments if needed
+    if (func->data.builtin.eval_args) {
+      eval_args = malloc(sizeof(node_t *) * arg_count);
+      if (!eval_args)
+        return NULL;
+
+      for (int i = 0; i < arg_count; i++) {
+        eval_args[i] = evaluate_node(ctx, args[i]);
+        if (!eval_args[i]) {
+          // Clean up on failure
+          for (int j = 0; j < i; j++) {
+            free_node(eval_args[j]);
+          }
+          free(eval_args);
+          return NULL;
+        }
+      }
+    }
+
+    int result = func->data.builtin.handler(eval_args, arg_count);
+
+    // Clean up evaluated arguments if we allocated them
+    if (func->data.builtin.eval_args) {
+      for (int i = 0; i < arg_count; i++) {
+        free_node(eval_args[i]);
+      }
+      free(eval_args);
+    }
+
+    return create_boolean_node(result == 0);
+  }
+
+  case FUNC_USER_DEFINED: {
+    fprintf(stderr, "DEBUG : BODY length %d\n",
+            func->data.user_defined.body->data.list.child_count);
+    if (func->data.user_defined.param_count != arg_count) {
+      fprintf(stderr, "Error: Function '%s' expects %d arguments, got %d\n",
+              name, func->data.user_defined.param_count, arg_count);
+      return NULL;
+    }
+
+    // Create new execution context
+    exec_context_t new_ctx = *ctx;
+
+    if (func->data.user_defined.param_count > 0) {
+      new_ctx.local_vars.count = func->data.user_defined.param_count;
+      new_ctx.local_vars.names =
+          malloc(sizeof(char *) * func->data.user_defined.param_count);
+      new_ctx.local_vars.values =
+          malloc(sizeof(node_t *) * func->data.user_defined.param_count);
+
+      for (int i = 0; i < func->data.user_defined.param_count; i++) {
+        new_ctx.local_vars.names[i] = func->data.user_defined.parameters[i];
+        new_ctx.local_vars.values[i] = evaluate_node(ctx, args[i]);
+        if (!new_ctx.local_vars.values[i]) {
+          // Clean up on failure
+          for (int j = 0; j < i; j++) {
+            free_node(new_ctx.local_vars.values[j]);
+          }
+          free(new_ctx.local_vars.names);
+          free(new_ctx.local_vars.values);
+          return NULL;
+        }
+      }
+    }
+
+    fprintf(stderr, "DEBUG : body %s\n",
+            func->data.user_defined.body->data.symbol);
+    node_t *result = evaluate_node(&new_ctx, func->data.user_defined.body);
+
+    // Clean up context
+    if (func->data.user_defined.param_count > 0) {
+      for (int i = 0; i < func->data.user_defined.param_count; i++) {
+        free_node(new_ctx.local_vars.values[i]);
+      }
+      free(new_ctx.local_vars.names);
+      free(new_ctx.local_vars.values);
+    }
+
+    return result;
+  }
+
+  case FUNC_REGISTRY: {
+    // Registry functions don't take arguments and don't return values
+    func->data.registry.func();
+    return create_boolean_node(true);
+  }
+
+  default:
+    fprintf(stderr, "Error: Unknown function type for '%s'\n", name);
+    return NULL;
+  }
+}
+
+int execute_command(const char *name) {
+  fprintf(stderr, "Looking for command %s\n", name);
+  unified_function_t *func = find_unified_function(name);
+  if (!func) {
+    return -1;
+  }
+
+  if (func->type == FUNC_REGISTRY) {
+    func->data.registry.func();
+    return 0;
+  } else if (func->type == FUNC_USER_DEFINED) {
+    fprintf(stderr, "DEBUG ; user definned %s \n", name);
+    exec_context_t ctx = {0};
+    node_t *result = evaluate_node(&ctx, func->data.user_defined.body);
+    if (result) {
+      free_node(result);
+      return 0;
+    }
+  }
+
+  return -1;
+}
+
+// Execute function call with context support
+node_t *execute_function_call_in_context(exec_context_t *ctx, node_t *call) {
+
+  if (call->type != NODE_FUNCTION_CALL) {
+    return NULL;
+  }
+  fprintf(stderr, "DEBUG : Call in context %s\n",
+          call->data.call.function_name);
+
+  return execute_unified_function(ctx, call->data.call.function_name,
+                                  call->data.call.args,
+                                  call->data.call.arg_count);
+}
diff --git a/src/lexer.c b/src/lexer.c
index 2783676..df5e5f1 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -1,5 +1,9 @@
 #include "../include/lexer.h"
+#include "../include/define.h"
+#include <ctype.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <sys/ucontext.h>
 
 token_t next_token(lexer_t *lexer) {
   token_t token = {0};
@@ -25,15 +29,18 @@ token_t next_token(lexer_t *lexer) {
   // Comma (function call indicator)
   if (lexer->current_char == ',') {
     token.type = TOKEN_COMMA;
+    token.value = (char *)malloc(2 * sizeof(char));
     token.value[0] = ',';
     token.value[1] = '\0';
     advance_char(lexer);
+    fprintf(stderr, "DEBUG : next token = ,\n");
     return token;
   }
 
   // Percent (function reference indicator)
   if (lexer->current_char == '%') {
     token.type = TOKEN_PERCENT;
+    token.value = (char *)malloc(2 * sizeof(char));
     token.value[0] = '%';
     token.value[1] = '\0';
     advance_char(lexer);
@@ -43,16 +50,20 @@ token_t next_token(lexer_t *lexer) {
   // Parentheses
   if (lexer->current_char == '(') {
     token.type = TOKEN_LPAREN;
+    token.value = (char *)malloc(2 * sizeof(char));
     token.value[0] = '(';
     token.value[1] = '\0';
     advance_char(lexer);
+    fprintf(stderr, "DEBUG : next token = (\n");
     return token;
   }
 
   if (lexer->current_char == ')') {
     token.type = TOKEN_RPAREN;
+    token.value = (char *)malloc(2 * sizeof(char));
     token.value[0] = ')';
     token.value[1] = '\0';
+    fprintf(stderr, "DEBUG : next token = )\n");
     advance_char(lexer);
     return token;
   }
@@ -63,8 +74,8 @@ token_t next_token(lexer_t *lexer) {
     advance_char(lexer); // Skip opening quote
 
     int i = 0;
-    while (lexer->current_char != '"' && lexer->current_char != '\0' &&
-           i < MAX_TOKEN_LENGTH - 1) {
+    while (lexer->current_char != '"' && lexer->current_char != '\0') {
+      token.value = (char *)realloc(token.value, (i + 1) * sizeof(char));
       if (lexer->current_char == '\\' && lexer->input[lexer->pos + 1] != '\0') {
         advance_char(lexer);
         switch (lexer->current_char) {
@@ -107,8 +118,8 @@ token_t next_token(lexer_t *lexer) {
 
     int i = 0;
     while (
-        (isalnum(lexer->current_char) || strchr("-+._", lexer->current_char)) &&
-        i < MAX_TOKEN_LENGTH - 1) {
+        (isalnum(lexer->current_char) || strchr("-+._", lexer->current_char))) {
+      token.value = (char *)realloc(token.value, (i + 1) * sizeof(char));
       token.value[i++] = lexer->current_char;
       advance_char(lexer);
     }
@@ -127,6 +138,7 @@ token_t next_token(lexer_t *lexer) {
         token.type = TOKEN_NUMBER;
       } else {
         token.type = TOKEN_SYMBOL;
+        fprintf(stderr, "DEBUG : next token = %s\n", token.value);
       }
     }
     return token;
@@ -134,7 +146,7 @@ token_t next_token(lexer_t *lexer) {
 
   // Error case
   token.type = TOKEN_ERROR;
-  snprintf(token.value, MAX_TOKEN_LENGTH, "Unexpected character '%c'",
+  snprintf(token.value, MAX_TOKEN_LENGTH - 1, "Unexpected character '%c'",
            lexer->current_char);
   return token;
 }
diff --git a/src/node.c b/src/node.c
new file mode 100644
index 0000000..ddf5e09
--- /dev/null
+++ b/src/node.c
@@ -0,0 +1,223 @@
+#include "../include/node.h"
+#include "../include/config_tools.h"
+#include "../include/define.h"
+#include "../include/function.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ucontext.h>
+
+// Node creation functions
+node_t *create_node(node_type_t type) {
+  node_t *node = malloc(sizeof(node_t));
+  if (!node)
+    return NULL;
+
+  memset(node, 0, sizeof(node_t));
+  node->type = type;
+  return node;
+}
+
+node_t *create_symbol_node(const char *symbol) {
+  node_t *node = create_node(NODE_SYMBOL);
+  if (node) {
+    node->data.symbol = (char *)malloc((MAX_SYMBOL_LENGTH - 1) * sizeof(char));
+    strncpy(node->data.symbol, symbol, MAX_SYMBOL_LENGTH - 1);
+    node->data.symbol[MAX_SYMBOL_LENGTH - 1] = '\0';
+  }
+  return node;
+}
+
+node_t *create_string_node(const char *string) {
+  node_t *node = create_node(NODE_STRING);
+  if (node) {
+    node->data.string = (char *)malloc((MAX_STRING_LENGTH - 1) * sizeof(char));
+    strncpy(node->data.string, string, MAX_STRING_LENGTH - 1);
+    node->data.string[MAX_STRING_LENGTH - 1] = '\0';
+  }
+  return node;
+}
+
+node_t *create_number_node(double number) {
+  node_t *node = create_node(NODE_NUMBER);
+  if (node) {
+    node->data.number = number;
+  }
+  return node;
+}
+
+node_t *create_boolean_node(bool value) {
+  node_t *node = create_node(NODE_BOOLEAN);
+  if (node) {
+    node->data.boolean = value;
+  }
+  return node;
+}
+
+node_t *create_function_ref_node(const char *function_name) {
+  node_t *node = create_node(NODE_FUNCTION_REF);
+  if (node) {
+    node->data.function_ref =
+        (char *)malloc((MAX_SYMBOL_LENGTH - 1) * sizeof(char));
+    strncpy(node->data.function_ref, function_name, MAX_SYMBOL_LENGTH - 1);
+    node->data.function_ref[MAX_SYMBOL_LENGTH - 1] = '\0';
+  }
+  return node;
+}
+
+node_t *create_function_call_node(const char *function_name) {
+  node_t *node = create_node(NODE_FUNCTION_CALL);
+  if (node) {
+    node->data.call.function_name =
+        (char *)malloc((MAX_SYMBOL_LENGTH - 1) * sizeof(char));
+    strncpy(node->data.call.function_name, function_name,
+            MAX_SYMBOL_LENGTH - 1);
+    node->data.call.function_name[MAX_SYMBOL_LENGTH - 1] = '\0';
+    node->data.call.arg_count = 0;
+  }
+  return node;
+}
+
+node_t *copy_node(node_t *src) {
+  if (!src)
+    return NULL;
+
+  node_t *copy = malloc(sizeof(node_t));
+  if (!copy)
+    return NULL;
+
+  copy->type = src->type;
+
+  switch (src->type) {
+  case NODE_STRING:
+    copy->data.string = strdup(src->data.string);
+    break;
+  case NODE_NUMBER:
+    copy->data.number = src->data.number;
+    break;
+  case NODE_BOOLEAN:
+    copy->data.boolean = src->data.boolean;
+    break;
+  case NODE_SYMBOL:
+    copy->data.symbol = strdup(src->data.symbol);
+    break;
+  case NODE_FUNCTION_REF:
+    copy->data.function_ref = strdup(src->data.function_ref);
+    break;
+  case NODE_LIST:
+    copy->data.list.child_count = src->data.list.child_count;
+    copy->data.list.children =
+        malloc(sizeof(node_t *) * src->data.list.child_count);
+    for (int i = 0; i < src->data.list.child_count; i++) {
+      copy->data.list.children[i] = copy_node(src->data.list.children[i]);
+    }
+    break;
+  case NODE_FUNCTION_CALL:
+    copy->data.call.function_name = strdup(src->data.call.function_name);
+    copy->data.call.arg_count = src->data.call.arg_count;
+    copy->data.call.args = malloc(sizeof(node_t *) * src->data.call.arg_count);
+    for (int i = 0; i < src->data.call.arg_count; i++) {
+      copy->data.call.args[i] = copy_node(src->data.call.args[i]);
+    }
+    break;
+  default:
+    free(copy);
+    return NULL;
+  }
+
+  return copy;
+}
+
+void free_node(node_t *node) {
+  int i;
+  if (!node)
+    return;
+
+  if (node->type == NODE_FUNCTION_CALL) {
+    for (i = 0; i < node->data.call.arg_count; i++) {
+      free_node(node->data.call.args[i]);
+    }
+    free(node->data.call.args);
+  } else if (node->type == NODE_LIST) {
+    for (i = 0; i < node->data.list.child_count; i++) {
+      free_node(node->data.list.children[i]);
+    }
+    free(node->data.list.children);
+  }
+
+  // Free string data if present
+  if (node->type == NODE_STRING && node->data.string) {
+    free(node->data.string);
+  } else if (node->type == NODE_SYMBOL && node->data.symbol) {
+    free(node->data.symbol);
+  } else if (node->type == NODE_FUNCTION_REF && node->data.function_ref) {
+    free(node->data.function_ref);
+  }
+
+  free(node);
+}
+
+// Evaluate a node in the given context
+node_t *evaluate_node(exec_context_t *ctx, node_t *node) {
+  fprintf(stderr, "DEBUG : evalute node type %d\n", node->type);
+  if (!node)
+    return NULL;
+
+  switch (node->type) {
+  case NODE_STRING:
+  case NODE_NUMBER:
+  case NODE_BOOLEAN:
+  case NODE_FUNCTION_REF:
+    return copy_node(node);
+
+  case NODE_SYMBOL: {
+    // Look up variable
+    for (int i = 0; i < ctx->local_vars.count; i++) {
+      if (strcmp(ctx->local_vars.names[i], node->data.symbol) == 0) {
+        return copy_node(ctx->local_vars.values[i]);
+      }
+    }
+
+    node_t *var = find_variable(node->data.symbol);
+    if (var) {
+      return copy_node(var);
+    }
+
+    fprintf(stderr, "Error: Undefined variable '%s'\n", node->data.symbol);
+    return NULL;
+  }
+
+  case NODE_FUNCTION_CALL:
+    fprintf(stderr, "DEBUG: function call : %s\n",
+            node->data.call.function_name);
+    return execute_function_call_in_context(ctx, node);
+
+  case NODE_LIST: {
+    // Execute all expressions in list and return last result
+    node_t *result = NULL;
+    fprintf(stderr, "DEBUG : child count %d\n", node->data.list.child_count);
+    for (int i = 0; i < node->data.list.child_count; i++) {
+      fprintf(stderr, "DEBUG : child number %d\n", i);
+      node_t *child = node->data.list.children[i];
+      if (result) {
+        free_node(result);
+      }
+      // Evaluate child and handle function calls
+      if (child->type == NODE_FUNCTION_CALL) {
+        result = execute_function_call_in_context(ctx, child);
+      } else {
+        result = evaluate_node(ctx, child);
+      }
+      if (!result) {
+        fprintf(stderr, "Error evaluating list element %d\n", i);
+        return NULL;
+      }
+    }
+    return result;
+  }
+
+  default:
+    fprintf(stderr, "Error: Cannot evaluate node type %d\n", node->type);
+    return NULL;
+  }
+}
diff --git a/src/parser.c b/src/parser.c
index ebf9557..8ffc376 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1,6 +1,28 @@
 #include "../include/parser.h"
+#include "../include/lexer.h"
+#include "../include/node.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 node_t *parse_atom(lexer_t *lexer, token_t *token) {
+  // Variable
+  node_t *list = NULL;
+  size_t saved_pos = 0;
+  int saved_line = 0;
+  int saved_column = 0;
+  char saved_char = '\000';
+
+  token_t peek;
+  token_t func_name;
+  token_t next;
+  token_t func_token;
+
+  node_t *call = NULL;
+  node_t *arg = NULL;
+  node_t *element = NULL;
+
+  // Code
   switch (token->type) {
   case TOKEN_SYMBOL:
     return create_symbol_node(token->value);
@@ -14,29 +36,169 @@ node_t *parse_atom(lexer_t *lexer, token_t *token) {
   case TOKEN_BOOLEAN:
     return create_boolean_node(strcmp(token->value, "true") == 0);
 
+  case TOKEN_LPAREN: {
+    fprintf(stderr, "DEBUG : list parsing\n");
+    list = create_list_node();
+
+    // Look ahead to see if this is a function call or just a list
+    saved_pos = lexer->pos;
+    saved_line = lexer->line;
+    saved_column = lexer->column;
+    saved_char = lexer->current_char;
+
+    peek = next_token(lexer);
+
+    // If first token is a comma, this is a function call
+    if (peek.type == TOKEN_COMMA) {
+      func_name = next_token(lexer);
+
+      if (func_name.type == TOKEN_SYMBOL) {
+        call = create_function_call_node(func_name.value);
+
+        // Parse arguments until closing paren
+        next = next_token(lexer);
+        while (next.type != TOKEN_RPAREN && next.type != TOKEN_EOF) {
+          arg = NULL;
+
+          if (next.type == TOKEN_PERCENT) {
+            // Function reference argument
+            func_token = next_token(lexer);
+            if (func_token.type == TOKEN_SYMBOL) {
+              arg = create_function_ref_node(func_token.value);
+            }
+          } else {
+            // Parse the argument expression recursively
+            arg = parse_expression(lexer, &next);
+          }
+
+          if (arg) {
+            add_arg_to_call(call, arg);
+          }
+
+          next = next_token(lexer);
+
+          // Skip commas between arguments
+          while (next.type == TOKEN_COMMA) {
+            next = next_token(lexer);
+          }
+        }
+
+        return call;
+      }
+    }
+
+    // Otherwise, parse as a regular list
+    // Restore lexer state
+    lexer->pos = saved_pos;
+    lexer->line = saved_line;
+    lexer->column = saved_column;
+    lexer->current_char = saved_char;
+
+    // Parse elements in the list
+    while (1) {
+      // Skip whitespace and comments
+      skip_whitespace(lexer);
+      skip_comment(lexer);
+      skip_whitespace(lexer);
+
+      // Check if we're at the end of the list
+      if (lexer->current_char == ')') {
+        // Consume the closing paren
+        lexer->pos++;
+        lexer->column++;
+        if (lexer->pos < strlen(lexer->input)) {
+          lexer->current_char = lexer->input[lexer->pos];
+        } else {
+          lexer->current_char = '\0';
+        }
+        break;
+      }
+
+      if (lexer->current_char == '\0') {
+        break;
+      }
+
+      // Parse the next element
+      element = parse_statement(lexer);
+      if (element) {
+        add_to_list(list, element);
+      } else {
+        // If we couldn't parse anything, advance one character to avoid
+        // infinite loop
+        lexer->pos++;
+        lexer->column++;
+        if (lexer->pos < strlen(lexer->input)) {
+          lexer->current_char = lexer->input[lexer->pos];
+        } else {
+          lexer->current_char = '\0';
+        }
+      }
+    }
+
+    return list;
+  }
+
   case TOKEN_PERCENT: {
     // Parse function reference: %function-name
-    token_t next = next_token(lexer);
+    next = next_token(lexer);
     if (next.type == TOKEN_SYMBOL) {
       return create_function_ref_node(next.value);
     }
     return NULL;
   }
 
+  case TOKEN_COMMA: {
+    // Function call at top level: ,function-name
+    func_token = next_token(lexer);
+    if (func_token.type == TOKEN_SYMBOL) {
+      return create_function_call_node(func_token.value);
+    }
+    return NULL;
+  }
+
   default:
     return NULL;
   }
 }
 
+node_t *parse_expression(lexer_t *lexer, token_t *token) {
+  if (!token) {
+    token_t current = next_token(lexer);
+    return parse_expression(lexer, &current);
+  }
+
+  // Check if this is a function call
+  if (token->type == TOKEN_COMMA) {
+    token_t func_token = next_token(lexer);
+    if (func_token.type == TOKEN_SYMBOL) {
+      return parse_function_call(lexer, func_token.value);
+    }
+    return NULL;
+  }
+
+  // Otherwise parse as atom
+  return parse_atom(lexer, token);
+}
+
 node_t *parse_function_call(lexer_t *lexer, const char *function_name) {
   node_t *call = create_function_call_node(function_name);
   if (!call)
     return NULL;
 
+  // Look for opening parenthesis (optional)
+  size_t saved_pos = lexer->pos;
+  int saved_line = lexer->line;
+  int saved_column = lexer->column;
+  char saved_char = lexer->current_char;
+
   token_t token = next_token(lexer);
+
   if (token.type != TOKEN_LPAREN) {
-    // Function call without parentheses - no arguments
-    printf("no paren\n");
+    // No parentheses, restore position and return call with no args
+    lexer->pos = saved_pos;
+    lexer->line = saved_line;
+    lexer->column = saved_column;
+    lexer->current_char = saved_char;
     return call;
   }
 
@@ -52,15 +214,21 @@ node_t *parse_function_call(lexer_t *lexer, const char *function_name) {
         arg = create_function_ref_node(func_token.value);
       }
     } else {
-      // Regular argument
-      arg = parse_atom(lexer, &token);
+      // Parse argument expression
+      arg = parse_expression(lexer, &token);
     }
 
     if (arg) {
       add_arg_to_call(call, arg);
     }
 
+    // Get next token
     token = next_token(lexer);
+
+    // Skip commas between arguments
+    while (token.type == TOKEN_COMMA) {
+      token = next_token(lexer);
+    }
   }
 
   return call;
@@ -73,13 +241,5 @@ node_t *parse_statement(lexer_t *lexer) {
 
   token_t token = next_token(lexer);
 
-  if (token.type == TOKEN_COMMA) {
-    // Function call: ,function-name(args)
-    token_t func_token = next_token(lexer);
-    if (func_token.type == TOKEN_SYMBOL) {
-      return parse_function_call(lexer, func_token.value);
-    }
-  }
-
-  return NULL;
+  return parse_expression(lexer, &token);
 }