Add evaluator with environment and file-based execution

Implements recursive AST evaluator with variable environment,
reads .j files from command line args, and executes programs
end-to-end (lexer -> parser -> eval).

src/main.c

@@ -1,38 +1,40 @@
-#include "frontend/parser.h"
-#include "objects/object.h"
+#include "vm/eval.h"
 
-int main() {
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    printf("usage: %s <path to .j file>\n", argv[0]);
+    exit(1);
+  }
   // Creamos un allocator
   JLANG_memory_allocator *allocPtr = JLANG_CreateAllocator();
 
-  size_t stringVar1 = obj_new_string(allocPtr, "Hello world!");
-  size_t floatVar1 = obj_new_float(allocPtr, 3.14);
-  size_t listVar1 = obj_new_list(allocPtr, 3);
-  Object *list = (Object *)JLANG_RESOLVE(allocPtr, listVar1);
+  // Read file from argv
+  FILE *fptr = fopen(argv[1], "r");
+  if (fptr == NULL) {
+    printf("error leyendo: %s\n", argv[1]);
+    exit(1);
+  }
 
-  size_t *items = (size_t *)JLANG_RESOLVE(allocPtr, list->data.list_val.items);
-  items[0] = floatVar1;
-  items[1] = stringVar1;
-  items[2] = listVar1;
+  fseek(fptr, 0, SEEK_END);  // ir al final
+  long length = ftell(fptr); // cuántos bytes tiene
+  fseek(fptr, 0, SEEK_SET);  // volver al inicio
+  char *buff = malloc(length + 1);
+  size_t bytesRead = fread(buff, 1, length, fptr);
+  buff[bytesRead] = '\0';
 
-  obj_print(allocPtr, listVar1, "");
+  fclose(fptr);
 
-  obj_free(allocPtr, stringVar1);
-
-  stringVar1 = obj_new_string(allocPtr, "Hola Mundo!");
-  items[1] = stringVar1;
-  items[2] = stringVar1;
-
-  obj_print(allocPtr, listVar1, "");
-
-  JLANG_visualize(allocPtr);
+  printf("%s\n", buff);
 
   // Lexer test
   int totalTokens = 0;
-  Token *tokens = tokenize("x = 10\ny = 5\nz = x + y\nprint z", &totalTokens);
+  Token *tokens = tokenize(buff, &totalTokens);
   printf("totalTokens=%d\n", totalTokens);
-  ASTNode* block = parse(tokens, totalTokens);
+  ASTNode *block = parse(tokens, totalTokens);
   ast_debug(block);
+  
+  Environment env = {0};
+  eval(block, &env, allocPtr);
 
   return 0;
 }