Add code to de-register patterns.

include/eval.h

@@ -74,9 +74,26 @@ struct eval_config_s {
   ll states;
 };
 
+/**
+ * Information about a state that has been
+ * added with eval_config_add.
+ */
+struct eval_state_s {
+  /**
+   * The string that was used to compile
+   * this state.
+   */
+  const char* source;
+  /**
+   * The pattern that was generated with this state.
+   */
+  pattern* pattern;
+};
+
 typedef struct match_s match;
 typedef struct eval_s eval;
 typedef struct eval_config_s eval_config;
+typedef struct eval_state_s eval_state;
 
 /**
  * Initializes the evaluation configuration.
@@ -97,6 +114,15 @@ liblex_result eval_config_free(eval_config* config);
  * @return LIBLEX_SUCCESS if all goes well, or LIBLEX_MALLOC if there was an allocation failure.
  */
 liblex_result eval_config_add(eval_config* config, const char* pattern, int pattern_id);
+/**
+ * Removes a pattern from this configuration that has been previously
+ * registered.
+ * @param config the configuration to add the pattern to.
+ * @param pattern the pattern to remove.
+ * @param pattern_id the id associated with the pattern.
+ * @return LIBLEX_SUCCESS if all goes well, or LIBLEX_MALLOC if there was an allocation failure.
+ */
+liblex_result eval_config_remove(eval_config* config, const char* pattern, int pattern_id);
 /**
  * Evaluates / finds a single word.
  * @param string the string to evaluate.

src/eval.c

@@ -16,30 +16,59 @@ void eval_config_init(eval_config* config){
 }
 liblex_result eval_config_add(eval_config* config, const char* ptrn, int pattern_id){
   liblex_result result;
-  pattern* new_pattern = malloc(sizeof(*new_pattern));
-  if(new_pattern){
+  pattern* new_pattern;
+  eval_state* new_state;
+  new_pattern = malloc(sizeof(*new_pattern));
+  new_state = malloc(sizeof(*new_pattern));
+  if(new_pattern && new_state){
     result = pattern_compile(new_pattern, ptrn, pattern_id);
     if(result == LIBLEX_SUCCESS){
-      result = (ll_append(&config->states, new_pattern) == LIBDS_SUCCESS) ?
+      new_state->source = ptrn;
+      new_state->pattern = new_pattern;
+      result = (ll_append(&config->states, new_state) == LIBDS_SUCCESS) ?
         LIBLEX_SUCCESS : LIBLEX_MALLOC;
     }
     if(result != LIBLEX_SUCCESS){
       pattern_free(new_pattern);
-      free(new_pattern);
     }
   } else {
     result = LIBLEX_MALLOC;
   }
+  if(result != LIBLEX_SUCCESS) {
+    free(new_pattern);
+    free(new_state);
+  }
   return result;
 }
 
-int _eval_config_foreach_free(void *data, va_list args){
-  pattern* ptrn = data;
-  int result = pattern_free(ptrn) == LIBLEX_SUCCESS ? 0 : EVAL_FOREACH_MALLOC;
-  free(ptrn);
+liblex_result _eval_config_free_state(eval_state* state) {
+  liblex_result result = pattern_free(state->pattern);
+  free(state->pattern);
+  free(state);
   return result;
 }
 
+liblex_result eval_config_remove(eval_config* config, const char* pattern, int pattern_id) {
+  liblex_result result = LIBLEX_SUCCESS;
+  ll_node** head = &(config->states.head);
+  while(*head && result == LIBLEX_SUCCESS) {
+    eval_state* current_state = (*head)->data;
+    if(strcmp(current_state->source, pattern) == 0 && current_state->pattern->head->pattern_id == pattern_id) {
+      ll_node* to_delete = *head;
+      (*head) = (*head)->next;
+      free(to_delete);
+      result = _eval_config_free_state(current_state);
+    } else {
+      head = &((*head)->next);
+    }
+  }
+  return result;
+}
+
+int _eval_config_foreach_free(void* data, va_list args){
+  return _eval_config_free_state(data) == LIBLEX_SUCCESS ? 0 : EVAL_FOREACH_MALLOC;
+}
+
 liblex_result eval_config_free(eval_config* config){
   liblex_result result = foreach_errors[ll_foreach(&config->states, NULL, compare_always, _eval_config_foreach_free)];
   ll_free(&config->states);
@@ -79,9 +108,9 @@ liblex_result _eval_pairmap_add_node(ht *table, pattern_node *node){
 }
 
 int _eval_foreach_add_node(void *data, va_list args){
-  pattern* new_pattern = data;
+  eval_state* state = data;
   ht* pairmap = va_arg(args, ht*);
-  pattern_node* pattern_head = new_pattern->head;
+  pattern_node* pattern_head = state->pattern->head;
   return _eval_pairmap_add_node(pairmap, pattern_head) == LIBLEX_SUCCESS? 0 : EVAL_FOREACH_MALLOC;
 }