prompt_formats
c->prompt_formats = ft;
format_free(c->prompt_formats);
c->prompt_formats = NULL;
tmp = format_expand_time(c->prompt_formats, input);
format_add(c->prompt_formats, "prompt-input", "%s", tmp);
prompt = format_expand_time(c->prompt_formats, c->prompt_string);
format_add(c->prompt_formats, "message", "%s", prompt);
format_add(c->prompt_formats, "command_prompt", "%d",
expanded = format_expand_time(c->prompt_formats, msgfmt);