On 17/03/16 11:47, [email protected] wrote:
That output goes through string_to_stdout in
snd-xen.c, I think (it's watched for via
g_io_channel_unix_get_fd in snd-gmain.c).
Snd used to have a print-hook for stuff like
this, but it didn't get used for years, so
I removed it. I could add a hook to
string_to_stdout to add a prompt, if you like.
I think you could change string_to_stdout
to
fprintf(stdout, "%s\n> ", msg);
or something like that to get a prompt,
but I haven't tried it.
Thanks Bill - I got the desired effect by editing snd_eval_stdin_str:
void snd_eval_stdin_str(const char *buf)
{
/* we may get incomplete expressions here */
/* (Ilisp always sends a complete expression, but it may be broken
into two or more pieces from read's point of view) */
char *str = NULL;
if (mus_strlen(buf) == 0) return;
str = stdin_check_for_full_expression(buf);
if (str)
{
Xen result;
int loc;
redirect_everything_to(string_to_stdout, NULL);
result = snd_catch_any(eval_str_wrapper, (void *)str, str);
redirect_everything_to(NULL, NULL);
loc = snd_protect(result);
stdin_free_str();
str = gl_print(result);
string_to_stdout(str, NULL);
/***** DANIEL: Next two lines added *****/
fprintf(stdout, ">>> ");
fflush(stdout);
if (str) free(str);
snd_unprotect_at(loc);
}
}
Putting it here makes the new prompt appear only once, after the result
and after any errors/warnings/snd-print statements that got printed out
via the redirect_everything_to/snd_catch_any calls.
The fflush() was necessary otherwise the new prompt it doesn't appear
until after the next console read (that confused me for a while, I can
tell you).
Also, to make the prompt appear once at program start, I added the same
two lines (fprintf and fflush) to g_xen_initialize(), right after where
it calls g_init_listener(). I suppose a more uniform solution would be
to make a new 'g_init_stdin()' function consisting of the new lines and
call that instead.
I was going to make a patch file of these changes to proudly present to
you but there are some other things to round out which I don't quite
have the tenacity to fully do right now - when starting up with
-nostdin, my hacked-in prompt spills onto stdout twice (once from
g_xen_initialize() and once from snd_eval_stdin_str() being called once
for some reason). And, it would also make sense if there was a built-in
'stdin-prompt' variable, similar to 'listener-prompt', for customizing
this. It would default to an empty string, not to disrupt the existing
default behaviour. I attempted this but my naive copy-pasting didn't
quite take me 100% of the way there, and to be honest my Scheme aptitude
is still a bit weak for this kind of thing. I might have another go at a
later date, unless you reckon these are jolly good ideas and get in
there first!
Daniel
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