Re: [PATCH] Feature: @local declares local variables.

[Kaz Kylheku]

On 2022-04-09 23:36, arnold@skeeve.com wrote:
> Hi Kaz.
>
> Thank you for submitting proposals for new features and for going
> to the trouble of implementing them. That is unusual and requires
> effort, which I appreciate.

Thanks for evaluating the patch. I agree with the remarks about
@local, including the annotation. I have jettisoned @local
entirely, and gone ahead with a more sophisticated feature: a single
@let statement that provides true block-scoped lexical variables.

Syntactically, it meets my use case as well as the annotation,
and has better semantics. Function-wide local variables are
a dodgy concept that is absent in our best programming languages.
Moreover, @let works outside of functions too, whereas the original
@local construct turned into a no-op.

So for instance, we can do this

  # one module's BEGIN block, out of many
  BEGIN {
    @let (x = 42)  # x is private, not visible anywhere else
      foo = x + 3  # foo is global
  }

This work is hosted at https://www.kylheku.com/cgit/egawk/about


> All that said, gawk is Free Software, and you are welcome to fork
> it and make (and support!) your own distribution.

By the way, I am a fan of your and Chet's "Fork My Code, Please"
manifesto; I have shared a link to that with people more than once.

> Quite seriously,
> you have my blessing if you wish to do this, and I'll be glad to
> answer questions you may have about the internals (although you seem
> to have a good handle on them already).

I have decided to call this "egawk" ("Enhanced Gawk").
The executable name is that, which allows it to be easily installed
side by side, in the same PATH as "gawk".

The gawk-bug utility will not installed by "make install", and
the --help usage looks like this:

$ egawk --help | egawk '/bugs/,/^$/'
To report bugs in Enhanced Gawk, send e-mail to
Kaz Kylheku <kaz at kylheku dot com>.
PLEASE do NOT try to report bugs or seek support in the original
bug-gawk mailing list, unless you can reproduce the issue with the
unmodified gawk program. Also do not report bugs in the comp.lang.awk
Usenet newsgroup, or in web forum such as Stack Overflow.