Re: [TCLCORE] backslash substitution documentation

[Offer K. <off...@gm...>]

On Mon, Jan 26, 2015 at 3:02 AM, John Ousterhout wrote:
> (I'll bet none of you thought I actually read these postings anymore, but
> sometimes I do!)
>

Hello Professor. It's an honor to have you answer my question. I'm
only sorry I couldn't reply earlier, it's been a crazy day at work.

>
> So, yes, backslash substitution did occur, but it happened in the list
> parser, long after the curly braces had been removed by the command parser.
>

Ah, this is the key piece of information I was missing. Looking at the
various official documentation pages I'm still unsure if I missed it
or if it's simply missing from Tcl's docs. Maybe something could be
added to the "list" documentation to clarify this?

> By the way, when I saw your message my first thought is that backslash
> substitution must actually be occurring inside the braces; I had to think
> for a bit to remind myself of the real answer above. I will admit that the
> multi-level parsing in Tcl can be confusing to people.

I think if you managed to explain it to me so clearly in 2 sentences a
short addition to the list command documentation should clear it up
that confusion for most people - or even prevent it in the first place
(the examples in the official documentation are really helpful in that
regard by the way!).

> It's quite simple and
> predictable once you understand it, but it's also quite different from
> virtually all other languages, so people don't expect it. People tend to
> assume that parsing happens once-and-for-all at a single place and point of
> time, but that's not how Tcl works. This feature is actually important for
> Tcl's extensibility, since it allows each command to interpret (i.e., parse)
> its arguments however it wants, without being constrained by any global
> notion of parsing. If Tcl did not have his behavior, it would be difficult
> for individual commands to introduce new syntaxes for their arguments.
>
> -John-

Thank you again Professor for taking the time to respond. It's very
much appreciated :)

Best regards,
Offer Kaye