Allow user to terminate the parser - close #13

assets/parser.c.erb

@@ -21,6 +21,7 @@
 #define P_UNEXPECTED_TOKEN 3u
 #define P_DROP 4u
 #define P_EOF 5u
+#define P_USER_TERMINATED 6u
 <% end %>
 
 /* An invalid ID value. */
@@ -737,12 +738,13 @@ static void state_values_stack_free(state_values_stack_t * stack)
  *
  * @param rule The ID of the rule.
  *
- * @return Parse value.
+ * @retval P_SUCCESS
+ *   Continue parsing.
+ * @retval P_USER_TERMINATED
+ *   User requested to terminate parsing.
  */
-static <%= @grammar.prefix %>value_t parser_user_code(uint32_t rule, state_values_stack_t * statevalues, uint32_t n_states)
+static size_t parser_user_code(<%= @grammar.prefix %>value_t * _pvalue, uint32_t rule, state_values_stack_t * statevalues, uint32_t n_states, <%= @grammar.prefix %>context_t * context)
 {
-    <%= @grammar.prefix %>value_t _pvalue = {0};
-
     switch (rule)
     {
 <% @grammar.rules.each do |rule| %>
@@ -755,7 +757,7 @@ static <%= @grammar.prefix %>value_t parser_user_code(uint32_t rule, state_value
     default: break;
     }
 
-    return _pvalue;
+    return P_SUCCESS;
 }
 
 /**
@@ -888,7 +890,12 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context)
         if (reduce_index != INVALID_ID)
         {
             /* We have something to reduce. */
-            reduced_parser_value = parser_user_code(parser_reduce_table[reduce_index].rule, &statevalues, parser_reduce_table[reduce_index].n_states);
+            <%= @grammar.prefix %>value_t reduced_parser_value2 = {0};
+            if (parser_user_code(&reduced_parser_value2, parser_reduce_table[reduce_index].rule, &statevalues, parser_reduce_table[reduce_index].n_states, context) == P_USER_TERMINATED)
+            {
+                return P_USER_TERMINATED;
+            }
+            reduced_parser_value = reduced_parser_value2;
             reduced_rule_set = parser_reduce_table[reduce_index].rule_set;
             state_values_stack_pop(&statevalues, parser_reduce_table[reduce_index].n_states);
             continue;
@@ -933,3 +940,16 @@ size_t <%= @grammar.prefix %>parse(<%= @grammar.prefix %>context_t * context)
 {
     return context->text_position;
 }
+
+/**
+ * Get the user terminate code.
+ *
+ * @param context
+ *   Lexer/parser context structure.
+ *
+ * @return User terminate code.
+ */
+size_t <%= @grammar.prefix %>user_terminate_code(<%= @grammar.prefix %>context_t * context)
+{
+    return context->user_terminate_code;
+}