feat: implement AST walker

src/compiler/fzl_parser.c

@@ -2,13 +2,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-char last_err[256];
+char plast_err[256];
 
 fzl_parser_t *fzl_mkparser(fzl_reader_ll_t *first)
 {
   if (!first)
   {
-    snprintf(last_err, sizeof(last_err), "token is null");
+    snprintf(plast_err, sizeof(plast_err), "token is null");
     return NULL;
   }
 
@@ -81,7 +81,7 @@ fzl_node_t *parse_primary(fzl_parser_t *parser)
     return fzl_mknode(FZL_NODETYPE_LITERAL, tok);
   }
 
-  snprintf(last_err, sizeof(last_err), "failed to parse primary at %d",
+  snprintf(plast_err, sizeof(plast_err), "failed to parse primary at %d",
            peek(parser)->i0);
   return NULL;
 }
@@ -126,7 +126,7 @@ fzl_node_t *parse_call(fzl_parser_t *parser)
       consume(parser);
     else if (peek(parser) && peek(parser)->type != FZL_TOKTYPE_RPAIR)
     {
-      snprintf(last_err, sizeof(last_err),
+      snprintf(plast_err, sizeof(plast_err),
                "expected ',' or ')' after arg list");
       return NULL;
     }
@@ -147,7 +147,7 @@ fzl_node_t *parse_expression(fzl_parser_t *parser, int precedence)
   else if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_STR_LITERAL)
     return parse_primary(parser);
 
-  snprintf(last_err, sizeof(last_err), "failed to parse expression at %d",
+  snprintf(plast_err, sizeof(plast_err), "failed to parse expression at %d",
            peek(parser)->i0);
   return NULL;
 }
@@ -184,7 +184,7 @@ fzl_node_t *parse_program(fzl_parser_t *parser)
 
   if (!first)
   {
-    snprintf(last_err, sizeof(last_err), "empty ;(");
+    snprintf(plast_err, sizeof(plast_err), "empty ;(");
     return NULL;
   }
 
@@ -204,7 +204,7 @@ int fzl_parse(fzl_parser_t *parser)
 
 // --- Parse zone end ---
 
-char *fzl_parser_geterror() { return last_err; }
+char *fzl_parser_geterror() { return plast_err; }
 
 void fzl_freenode(fzl_node_t *node)
 {
@@ -220,17 +220,16 @@ void fzl_freeast(fzl_node_t *root)
 
   while (root)
   {
-    if (root->type == FZL_NODETYPE_BLOCK)
+    if (root->type == FZL_NODETYPE_BLOCK || root->type == FZL_NODETYPE_CALL)
     {
-      for (size_t i = 0; i < root->list.entry_count; i++)
-        if (root->list.entries[i])
-          fzl_freeast(root->list.entries[i]);
-    }
-    else if (root->type == FZL_NODETYPE_CALL)
-    {
-      for (size_t i = 0; i < root->list.entry_count; i++)
-        if (root->list.entries[i])
-          fzl_freeast(root->list.entries[i]);
+      if (root->list.entries)
+      {
+        for (size_t i = 0; i < root->list.entry_count; i++)
+          if (root->list.entries[i])
+            fzl_freeast(root->list.entries[i]);
+
+        free(root->list.entries);
+      }
     }
 
     fzl_freenode(root);