support lookups via language servers (LSP)HEADmaster-fmsbw-cimaster

* The main interface is the `FT` command.
  `FT` was an undocumented Video TECO command for etags/ctags lookups.
  I don't want to exactly copy its interface, though.
* `FT` allows looking up symbol names,
  definitions and references.
* ctags will be supported via ctags-lsp.
  LSP support is more powerful though and works without
  regenerating TAGS files all the time.
  The LSP will also allow you to customize auto-completions
  using SciTECO itself (i.e. by writing a language server
  in SciTECO).
* For multiple results, `FT$` can be used to cycle through
  results - this should mimic repeated `S$` or `N$`.
* `:FT...$` does a fuzzy search. IMHO it's not important
  to return a status integer instead. `FT` will only
  really be used in interactive mode.
* Document synchronization is supported via hooks from
  ring.c and via Scintilla notifications.
* Currently, the LSP communication is based on blocking
  GIOChannels. This means that a misbehaving hanging
  server could "lock up" the entire editor (FIXME).
  Only on ncurses you can always kill the subprocess by
  pressing CTRL+C.
  We need helper functions in spawn.c to read and write
  with interruptions.
* The textDocument/didChange notification transmits
  not only all edits, but all files' contents as well
  during initial synchronization.
  Therefore it is optimized to write and JSON-escape
  data without copying them around in memory and without
  destroying the buffer gap.
* Use $SCITECO_LSP to configure the language server.
  You can also use `tee` to capture stdin and stdout.
  Perhaps $SCITECO_LSP should be saved in .teco_session,
  so you can change it between projects?
* $SCITECO_LSP_ROOT is used to point to the project's
  root directory. session.tes will set it up automatically.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/help.c b/src/help.c
index c64538e..b7b5fd0 100644
--- a/src/help.c
+++ b/src/help.c
@@ -282,6 +282,11 @@ teco_state_help_done(teco_machine_main_t *ctx, teco_string_t str, GError **error
 		                    "Help topic must not contain null-byte");
 		return NULL;
 	}
+
+	/*
+	 * FIXME: Perhaps ?$ could toggle through all topics with the
+	 * same name.
+	 */
 	const gchar *topic_name = str.data ? : "";
 	teco_help_topic_t *topic = teco_help_find(topic_name);
 	if (!topic) {