[Python-3000] Switch and static, redux

[Guido van Rossum]

On 7/7/06, Georg Brandl <g.brandl at gmx.net> wrote:
> Ka-Ping Yee wrote:
> > On Wed, 5 Jul 2006, Guido van Rossum wrote:
> >> So, my proposal is to give up on static, accept PEP 3103 with the
> >> following options:
> >>   - Syntax alternative 2+B (unindented cases, 'case in ...' for
> >>     multiple cases).
> >>   - Semantics option 3 (def-time freezing)
> >>
> >> Do we need any more discussion about the PEP before I pronounce? (I'm
> >> not super confident about the syntax alternatives yet.)
> >
> > I think i'd argue for indented cases, mainly because it's what
> > everyone expects.  "Everyone" includes
> >
> >   - people who have seen 'switch' in other languages
> >   - people who expect ':' to introduce an indented block
> >   - editors that autoindent new lines
> >   - editors that fold indented blocks
> >   - editor hotkeys/macros for manipulating indented blocks
> >   - tools that highlight Python code
> >   - interactive Python consoles
>
> I agree with Ping here. Indented cases are more consistent,

I think I've been convinced. I'll update the PEP.

> unless
> we come up with something to fill the "empty switch suite", such as
>
> switch expr:
> case 1:
>     ...
>
> vs
>
> switch:
>     expr
> case 1:
>     ...

I don't think anything like this is likely to displace syntax
alternatives 1-4 in PEP 3103l, so I recommend that people not bother
to try.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)