From a2049660142b0aed94fb880f664cb2098dc7d313 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Hru=C5=A1ka?= <ondra@ondrovo.com>
Date: Sun, 21 Nov 2021 16:16:08 +0100
Subject: [PATCH] implement MARKER

---
 src/fh_builtins_meta.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/src/fh_builtins_meta.c b/src/fh_builtins_meta.c
index 84fc652..be5e818 100644
--- a/src/fh_builtins_meta.c
+++ b/src/fh_builtins_meta.c
@@ -31,6 +31,42 @@ static enum fh_error w_colon(struct fh_thread_s *fh, const struct fh_word_s *w)
   return FH_OK;
 }
 
+static enum fh_error rt_marker(struct fh_thread_s *fh, const struct fh_word_s *w)
+{
+  LOG("Restore dict to landmark sate \"%s\"", w->name);
+  fh->dict_last = w->param;
+  return FH_OK;
+}
+
+static enum fh_error w_marker(struct fh_thread_s *fh, const struct fh_word_s *w)
+{
+  (void) w;
+  enum fh_error rv;
+  ENSURE_STATE(FH_STATE_INTERPRET);
+
+  char *wordname = NULL;
+  size_t namelen = 0;
+  fh_input_consume_spaces(fh);
+  TRY(fh_input_read_word(fh, &wordname, &namelen));
+  LOG("Marker name: %.*s", namelen, wordname);
+
+  uint32_t ptr;
+  TRY(fh_heap_reserve(fh, DICTWORD_SIZE, &ptr));
+
+  struct fh_word_s *new_word = fh_word_at(fh, ptr);
+  if (!new_word) return FH_ERR_INTERNAL;
+  new_word->previous = fh->dict_last;
+  new_word->param = fh->dict_last;
+  new_word->handler = rt_marker;
+  strncpy(new_word->name, wordname, namelen);
+  new_word->name[namelen] = 0;
+  new_word->flags = WORDFLAG_WORD;
+
+  fh->dict_last = ptr;
+
+  return FH_OK;
+}
+
 static enum fh_error w_colon_noname(struct fh_thread_s *fh, const struct fh_word_s *w)
 {
   (void) w;
@@ -655,5 +691,6 @@ const struct name_and_handler fh_builtins_meta[] = {
     {"[']",          wp_tick,        1, 1},
     {"execute",      w_execute,      0, 0},
     {"environment?", w_env_query,    0, 0},
+    {"marker",       w_marker,       0, 0},
     { /* end marker */ }
 };