lib: Implement node comparison function

Implement comparator for nodes, some miscellaneous cleanup.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

1 files changed, 33 insertions, 11 deletions

diff --git a/lib/cmdtree.h b/lib/cmdtree.h
index 9b512e3bb9..3d2366b008 100644
--- a/lib/cmdtree.h
+++ b/lib/cmdtree.h
@@ -20,20 +20,23 @@ struct graph_node
 {
   enum graph_node_type type;
   vector children;
-  int is_root;      // true if first token in command
-  int is_leaf;      // true if last token in command
+  int is_root;              // true if first token in command
+  int is_leaf;              // true if last token in command
+  struct graph_node * end;  // pointer to end for selector & option
 
   int (*func)(struct vty *, int, const char *[]);
 
   /* various data fields for nodes */
   char* text;       // for words and variables
   int value;        // for numbers
-  int start, end;   // for ranges
+  int min, max;     // for ranges
 };
 
 /*
- * Adds a child to a node. If the node already has the exact same
- * child, nothing is done.
+ * Adds a child to a node.
+ * If the node already has the exact same child, nothing is done. This is
+ * decided with cmp_node.
+ *
  * @param[in] parent node
  * @param[in] child node
  * @return the new child, or the existing child if the parent already has the
@@ -43,16 +46,35 @@ extern struct graph_node *
 add_node(struct graph_node *, struct graph_node *);
 
 /*
- * Compares two nodes for equivalence.
- * What exactly constitutes two nodes being equal depends on the
- * node type.
- * @return 0 if equal, nonzero otherwise.
+ * Compares two nodes for parsing equivalence.
+ * Equivalence in this case means that a single user input token
+ * should be able to unambiguously match one of the two nodes.
+ * For example, two nodes which have all fields equal except their
+ * function pointers would be considered equal.
+ *
+ * @param[in] first node to compare
+ * @param[in] second node to compare
+ * @return 1 if equal, zero otherwise.
  */
 extern int
-cmp_node(struct graph_node *first, struct graph_node *second);
+cmp_node(struct graph_node *, struct graph_node *);
 
+/*
+ * Create a new node.
+ * Initializes all fields to default values and sets the node type.
+ *
+ * @param[in] node type
+ * @return pointer to the newly allocated node
+ */
 extern struct graph_node *
-new_node(enum graph_node_type type);
+new_node(enum graph_node_type);
 
+/**
+ * Walks a command DFA, printing structure to stdout.
+ * For debugging.
+ *
+ * @param[in] start node of graph to walk
+ * @param[in] graph depth for recursion, caller passes 0
+ */
 extern void
 walk_graph(struct graph_node *, int);