h_put_value and h_get_value done.

src/parsers/value.c

@@ -0,0 +1,69 @@
+#include "parser_internal.h"
+
+typedef struct {
+  const HParser* p;
+  const char* key;
+} HStoredValue;
+
+/* Stash an HParseResult into a symbol table, so that it can be 
+   retrieved and used later. */
+
+static HParseResult* parse_put(void *env, HParseState* state) {
+  HStoredValue *s = (HStoredValue*)env;
+  if (s->p && s->key && !h_symbol_get(state, s->key)) {
+    HParseResult *tmp = h_do_parse(s->p, state);
+    if (tmp) {
+      h_symbol_put(state, s->key, tmp);
+    }
+    return tmp;
+  } 
+  // otherwise there's no parser, no key, or key's stored already
+  return NULL;
+}
+
+static const HParserVtable put_vt = {
+  .parse = parse_put,
+  .isValidRegular = h_false,
+  .isValidCF = h_false,
+  .compile_to_rvm = h_not_regular,
+};
+
+HParser* h_put_value(const HParser* p, const char* name) {
+  return h_put_value__m(&system_allocator, p, name);
+}
+
+HParser* h_put_value__m(HAllocator* mm__, const HParser* p, const char* name) {
+  HStoredValue *env = h_new(HStoredValue, 1);
+  env->p = p;
+  env->key = name;
+  return h_new_parser(mm__, &put_vt, env);
+}
+
+/* Retrieve a stashed result from the symbol table. */
+
+static HParseResult* parse_get(void *env, HParseState* state) {
+  HStoredValue *s = (HStoredValue*)env;
+  if (!s->p && s->key) {
+    return h_symbol_get(state, s->key);
+  } else { // either there's no key, or there was a parser here
+    return NULL;
+  }
+}
+
+static const HParserVtable get_vt = {
+  .parse = parse_get,
+  .isValidRegular = h_false,
+  .isValidCF = h_false,
+  .compile_to_rvm = h_not_regular,
+};
+
+HParser* h_get_value(const char* name) {
+  return h_get_value__m(&system_allocator, name);
+}
+
+HParser* h_get_value__m(HAllocator* mm__, const char* name) {
+  HStoredValue *env = h_new(HStoredValue, 1);
+  env->p = NULL;
+  env->key = name;
+  return h_new_parser(mm__, &get_vt, env);
+}