Subj : ESC key in user input
To : Nightfox
From : Digital Man
Date : Sun Feb 07 2010 12:54 pm
Re: ESC key in user input
By: Nightfox to All on Sat Feb 06 2010 06:02 pm
> In writing JavaScript mods for Synchronet, I've noticed some oddness
> related to checking for the ESC key in user input.
>
> I've noticed that there is no key variable defined for ESC in sbbsdefs.js,
> so I've always defined it in my own scripts as "\x1b" (alternatively,
> defining the ESC key using ascii(27) also seems to work).
>
> In one script where I use a lightbar user interface, checking for the ESC
> key apparently caused the script to quit unexpectedly when scrolling too
> fast through the list of items by holding down the up or down arrow keys;
> the problem went away when I removed the check for the ESC key. I've also
> noticed that Synchronet JavaScript mods tend to take a second or two to
> respond to the ESC key, although I've seen that in other doors too,
> including older DOS doors (i.e., IceEdit).
>
> Is there an issue with checking for the ESC key in user input?
Yes. Terminal escape sequences (e.g. ANSI) often begin with the escape (ASCII
27) character, for example <ESC>[2J to clear the screen.
> Are the
> issues that I've mentioned common, and are there any ways to get around
> them (besides not checking for ESC)?
You'd have use a timeout mechanism, which explains the delay you see in some
scripts/programs that support ESC as a command.
digital man
Snapple "Real Fact" #155:
In 1926, the first outdoor mini-golf courses were built on rooftops in NYC.
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