New EEP draft: Pinning operator ^ in patterns

A. G. Madi viper7129@REDACTED
Thu Jan 14 15:50:30 CET 2021

I completely agree with Nicolas. This makes me very nervous.

On Thu, Jan 14, 2021 at 08:41 Nicolas Martyanoff <khaelin@REDACTED> wrote:

> On 2021-01-14 14:13, Richard Carlsson wrote:
> > The way I planned it is:
> >   1. Even from the start, pinning will always be allowed, without
> requiring
> > any flag to opt in. This does not tell you about existing uses of
> > already-bound variables, but you can start using pinning right away for
> > readability and for avoiding bugs when refactoring. The compiler will
> > always tell you if a pinned variable doesn't exist, so you don't
> > accidentally accept any value in that position.
> >   2. You can enable warnings at your own pace in order to start cleaning
> up
> > your code.
> >   3. In a following major release, the warnings will be on by default,
> but
> > you can disable them to compile old code.
> >   4. In a distant future, it might become an error to not use ^ to mark
> > already-bound variables.
> After reading this thread, I must say this proposal makes me uneasy. One of
> the things I always liked with Erlang is the simplicity and clarity of its
> syntax. Matching variables by name is perfectly readable to me, and I never
> had any problem of the sort refactoring code. Adding a new operator adds
> noise and transforms something simple (using the same name to refer to the
> same value) into something cryptic.
> The fact that you envision a future where not using the operator would
> signal
> an error is even more worrisome. I have nothing against improving the core
> parts of the language (maps were a life changer for example), but this
> kind of
> change feels really foreign to the simplicity of the Erlang syntax.
> And at the risk of sounding too harsh, I would add that while I do not
> mind the
> existence of Elixir (quite the opposite, it brought a lot of fresh air to
> the
> entire BEAM ecosystem), I would really like Erlang to remain Erlang; in
> that
> spirit, I see a new operator to "annotate" a perfectly clear and working
> syntax as useless.
> Regards,
> --
> Nicolas Martyanoff
> khaelin@REDACTED
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