feat: implement loops

include/compiler/fzl_parser.h

@@ -18,6 +18,7 @@ typedef enum
   FZL_NODETYPE_CLASS,
   FZL_NODETYPE_FIELD,
   FZL_NODETYPE_CONSTRUCT,
+  FZL_NODETYPE_LOOP,
 
   FZL_NODETYPE_ADD,
   FZL_NODETYPE_SUB,
@@ -140,6 +141,16 @@ typedef struct fzl_node
     {
       struct fzl_node *name;
     } construct;
+
+    // Loop
+    struct
+    {
+      struct fzl_node *init;
+      struct fzl_node *cond;
+      struct fzl_node *step;
+
+      struct fzl_node *body;
+    } loop;
   };
 } fzl_node_t;