Re: [Bug-apl] aplwrap: bell & ANSI controls

[David B. Lamkins]

I wrote an ANSI terminal emulator decades ago. It's not a small task.

Even if you take a small subset of the control codes, there are still
some tricky architectural issues to consider w.r.t. how a screen-based
console would function within the transcript-based model presented by
aplwrap.

If you've seen Dyalog's Linux offering: they've dealt with this by
offering a separate mode (and window) for screen-based output.

I'd have to give some more thought to this...

In the meantime: I'll reiterate Chris's comment about being aware of the
TERM environment variable. This, together with shelling out to tput to
get terminal-appropriate control codes, can be used to make your program
support a wide variety of terminals; not just ANSI-compatible. Of course
you'll need to provide a fallback for the case where tput tells you that
your terminal doesn't possess the requested capability...

Chris: It might be a good idea to pick a glyph other than blank as a
substitution character. U+FFFD seems like a good choice:

http://en.wikipedia.org/wiki/Specials_%28Unicode_block%29

Re: Bell not working: just a misplaced line:

diff --git a/src/txtbuf.c b/src/txtbuf.c
index a98cf23..21020b1 100644
--- a/src/txtbuf.c
+++ b/src/txtbuf.c
@@ -52,8 +52,8 @@ tagged_insert (char   *text,
       ptr = g_utf8_next_char (ptr);
       if (!g_unichar_isprint (c) && *op != '\n') {
        gint cl = ptr - op;
-       for (int i = 0; i < cl; i++) *op++ = ' ';
        if (*op == '\a') gdk_beep ();
+       for (int i = 0; i < cl; i++) *op++ = ' ';
       }
     }
   }