public and copy rule and symbol functions

[cascardo/grammar.git] / grammar.c

diff --git a/grammar.c b/grammar.c
index 72248e0..2b56a3a 100644 (file)
--- a/grammar.c
+++ b/grammar.c
@@ -14,6 +14,11 @@ symbol_t* symbol_new (gboolean terminal, gint value)
   return symbol;
 }
 
+symbol_t* symbol_copy (symbol_t* symbol)
+{
+  return symbol_new (symbol->terminal, symbol->value);
+}
+
 guint symbol_hash (gconstpointer data)
 {
   symbol_t* symbol;
@@ -44,6 +49,33 @@ void rule_append (rule_t* rule, symbol_t* right)
   rule->right = g_list_append (rule->right, right);
 }
 
+rule_t* rule_copy (rule_t* rule)
+{
+  rule_t* new_rule;
+  GList* r;
+  new_rule = rule_new ();
+  r = rule->right;
+  while (r != NULL)
+    {
+      rule_append (new_rule, symbol_copy (r->data));
+      r = g_list_next (r);
+    }
+  return new_rule;
+}
+
+symbol_t* rule_pop (rule_t* rule)
+{
+  GList* r;
+  if ((r = g_list_first (rule->right)) == NULL)
+    return NULL;
+  rule->right = g_list_remove_link (r, r);
+  g_free (r->data);
+  g_list_free (r);
+  if (rule->right == NULL)
+    return NULL;
+  return rule->right->data;
+}
+
 void rule_delete (rule_t* rule)
 {
   GList* l;
@@ -124,6 +156,7 @@ rule_t* grammar_rule_new (Grammar* grammar, symbol_t* left)
                                     left, NULL, (gpointer*)&l))
     {
       l = g_malloc (sizeof (GList**));
+      *l = NULL;
       g_hash_table_insert (grammar->grammar, left, l);
     }
 
@@ -135,7 +168,18 @@ rule_t* grammar_rule_new (Grammar* grammar, symbol_t* left)
 
 }
 
-void grammar_rule_append (rule_t* rule, symbol_t* right)
+GList* grammar_get_rules (Grammar* grammar, symbol_t* left)
+{
+  GList** l;
+  if (!g_hash_table_lookup_extended (grammar->grammar,
+                                    left, NULL, (gpointer*)&l))
+    {
+      return NULL;
+    }
+  return g_list_first (*l);
+}
+
+GList* grammar_get_rule (rule_t* rule)
 {
-  rule_append (rule, right);
+  return rule->right;
 }