Add function node parsing.

src/tree.c

@@ -5,21 +5,30 @@ int libab_tree_has_vector(libab_tree_variant variant) {
     return variant == BASE || variant == OP ||
             variant == UNARY_OP || variant == BLOCK ||
             variant == IF || variant == CALL || variant == WHILE ||
-            variant == DOWHILE;
+            variant == DOWHILE || variant == FUN;
 }
 
 int libab_tree_has_string(libab_tree_variant variant) {
     return variant == ID || variant == NUM ||
-            variant == OP || variant == UNARY_OP;
+            variant == OP || variant == UNARY_OP ||
+            variant == FUN || variant == FUN_PARAM;
+}
+
+int libab_tree_has_type(libab_tree_variant variant) {
+    return variant == FUN_PARAM || variant == FUN;
 }
 
 void libab_tree_free(libab_tree* tree) {
     int free_string = 0;
     int free_vector = 0;
+    int free_type = 0;
     free_vector = libab_tree_has_vector(tree->variant);
     free_string = libab_tree_has_string(tree->variant);
+    free_type = libab_tree_has_type(tree->variant);
     if(free_string) free(tree->string_value);
     if(free_vector) vec_free(&tree->children);
+    if(free_type && tree->parse_type)
+        libab_parsetype_free_recursive(tree->parse_type);
 }
 
 int _tree_foreach_free(void* data, va_list args) {