Refactor ALL the things!

src/parsers/optional.c

@@ -0,0 +1,26 @@
+#include "parser_internal.h"
+
+static HParseResult* parse_optional(void* env, HParseState* state) {
+  HInputStream bak = state->input_stream;
+  HParseResult *res0 = h_do_parse((HParser*)env, state);
+  if (res0)
+    return res0;
+  state->input_stream = bak;
+  HParsedToken *ast = a_new(HParsedToken, 1);
+  ast->token_type = TT_NONE;
+  return make_result(state, ast);
+}
+
+static const HParserVtable optional_vt = {
+  .parse = parse_optional,
+};
+
+const HParser* h_optional(const HParser* p) {
+  // TODO: re-add this
+  //assert_message(p->vtable != &ignore_vt, "Thou shalt ignore an option, rather than the other way 'round.");
+  HParser *ret = g_new(HParser, 1);
+  ret->vtable = &optional_vt;
+  ret->env = (void*)p;
+  return ret;
+}
+