From 913cc5882449b5016f4db07edbd8566dc877b389 Mon Sep 17 00:00:00 2001
From: petermlm <pedromelgueira@gmail.com>
Date: Tue, 31 May 2016 22:32:24 +0100
Subject: [PATCH] Made traversal free

---
 examples/tree_traversal.c | 21 ++++++++++++++++++++-
 mpc.c                     | 11 +++++++++++
 mpc.h                     |  2 ++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/examples/tree_traversal.c b/examples/tree_traversal.c
index 7553cdd..88a5537 100644
--- a/examples/tree_traversal.c
+++ b/examples/tree_traversal.c
@@ -8,7 +8,7 @@ int main(int argc, char *argv[]) {
   mpc_ast_t *ast, *tree, *child, *child_sub, *ast_next;
   mpc_ast_trav_t *trav;
   mpc_result_t r;
-  int index, lb;
+  int index, lb, i;
 
   mpca_lang(MPCA_LANG_PREDICTIVE,
         " node : '(' <node> ',' /foo/ ',' <node> ')' | <leaf>;"
@@ -79,6 +79,8 @@ int main(int argc, char *argv[]) {
     ast_next = mpc_ast_traverse_next(&trav);
   }
 
+  mpc_ast_traverse_free(&trav);
+
   printf("Post order tree traversal.\n");
 
   trav = mpc_ast_traverse_start(ast, mpc_ast_trav_order_post);
@@ -92,6 +94,23 @@ int main(int argc, char *argv[]) {
     ast_next = mpc_ast_traverse_next(&trav);
   }
 
+  mpc_ast_traverse_free(&trav);
+
+  printf("Partial traversal.\n");
+
+  trav = mpc_ast_traverse_start(ast, mpc_ast_trav_order_post);
+
+  ast_next = mpc_ast_traverse_next(&trav);
+
+  for(i=0; i<2 && ast_next != NULL; i++) {
+    printf("Tag: %s; Contents: %s\n",
+      ast_next->tag,
+      ast_next->contents);
+    ast_next = mpc_ast_traverse_next(&trav);
+  }
+
+  mpc_ast_traverse_free(&trav);
+
   /* Clean up and return */
   mpc_cleanup(3, Node, Leaf, Input);
   mpc_ast_delete(ast);
diff --git a/mpc.c b/mpc.c
index 29e78c4..cba873f 100644
--- a/mpc.c
+++ b/mpc.c
@@ -2933,6 +2933,17 @@ mpc_ast_t *mpc_ast_traverse_next(mpc_ast_trav_t **trav) {
   return ret;
 }
 
+void mpc_ast_traverse_free(mpc_ast_trav_t **trav) {
+  mpc_ast_trav_t *n_trav;
+
+  /* Go through parents until all are free */
+  while(*trav != NULL) {
+      n_trav = (*trav)->parent;
+      free(*trav);
+      *trav = n_trav;
+  }
+}
+
 mpc_val_t *mpcf_fold_ast(int n, mpc_val_t **xs) {
   
   int i, j;
diff --git a/mpc.h b/mpc.h
index 1ac123a..5dec3af 100644
--- a/mpc.h
+++ b/mpc.h
@@ -298,6 +298,8 @@ mpc_ast_trav_t *mpc_ast_traverse_start(mpc_ast_t *ast,
 
 mpc_ast_t *mpc_ast_traverse_next(mpc_ast_trav_t **trav);
 
+void mpc_ast_traverse_free(mpc_ast_trav_t **trav);
+
 /*
 ** Warning: This function currently doesn't test for equality of the `state` member!
 */