[REBOL] Re: Input validation routines
From: greggirwin:mindspring at: 27-Aug-2003 9:02
Hi Robert,
RMM> BTW: Do you have a reference how those format strings are expressed? I
RMM> mean we have dialects and I'm sure we can clone this common way. I would
RMM> follow the common way, as a lot of people know it.
I think the COBOL PIC format was the initial inspiration that a lot of
others emulated and built upon. Clipper might have been the king, but
a true DB person could probably say for sure.
RMM> IMO in this case a check-as-you-type handler is needed. This handler
RMM> will analyze the string (on a positional base) and insert the dots at
RMM> the right place ;-)) and update the GUI. Robert
That kind of thing can be *very* hard to get right Robert, in my
experience. It's not just the technical side of things, but the user
interaction experience you design. Having things modified as you type
can confuse some people, and can end up being a lot of work if you get
into things like masks where you want to skip over some chars
automatically when they cursor or backspace, not to mention
shift+cursor to highlight text then typing or hitting delete or
backspace. Even if you get it to work how *you* want, some users will
just never be comfortable with it.
I'm all for *anything* that helps users, but validation after the fact
and better help information to show them what's valid can be used
with the same prototype-form approach, just without the key-level
interaction bit. I guess I'm saying I'd get the validation part
working before worrying about key-handling integration.
Just FWIW.
-- Gregg
