fix memleak; initialization boilerplate

ast.c

@@ -28,9 +28,8 @@ Ast astParse(const char* source, const uint32_t len) {
             exit(1);
         }
         TokenizerToken token = tokenizerNext(&tok);
-        tokens.tags[tokens.len] = token.tag;
+        tokens.tags[++tokens.len] = token.tag;
         tokens.starts[tokens.len] = token.loc.start;
-        tokens.len++;
         if (token.tag == TOKEN_EOF)
             break;
     }
@@ -58,10 +57,19 @@ Ast astParse(const char* source, const uint32_t len) {
         .scratch = SLICE_INIT(AstNodeIndex, N)
     };
 
-    free(p.scratch.arr); // Parser takes ownership
-
     parseRoot(&p);
 
+    p.nodes.cap = p.nodes.len = 0;
+    free(p.nodes.tags);
+    free(p.nodes.main_tokens);
+    free(p.nodes.datas);
+
+    p.extra_data.cap = p.extra_data.len = 0;
+    free(p.extra_data.arr);
+
+    p.scratch.cap = p.scratch.len = 0;
+    free(p.scratch.arr);
+
     return (Ast) {
         .source = source,
         .source_len = len,
@@ -74,3 +82,19 @@ Ast astParse(const char* source, const uint32_t len) {
         },
     };
 }
+
+void astDeinit(Ast* tree) {
+    tree->tokens.cap = tree->tokens.len = 0;
+    free(tree->tokens.tags);
+    free(tree->tokens.starts);
+
+    tree->nodes.cap = 0;
+    tree->nodes.len = 0;
+    free(tree->nodes.tags);
+    free(tree->nodes.main_tokens);
+    free(tree->nodes.datas);
+
+    tree->extra_data.cap = 0;
+    tree->extra_data.len = 0;
+    free(tree->extra_data.arr);
+}