[Python-ideas] 'where' statement in Python? (original) (raw)

Alex Light scialexlight at gmail.com
Wed Jul 21 12:35:42 CEST 2010

nick coughlan wrote:

No, the idea is for the indented suite to be a perfectly normal suite of Python code. We want to be able to define functions, classes, etc in there. @Chris Robert sorry what i meant in saying that " a_variable = an_expression" is that, it seems to me, at least, the only allowed statements are ones where a variable is set to a value, which includes "class" and "def" (and some control flow, if, else etc.)

also in the first post: Sergio Davis wrote:

I'm considering the following extension to Python's grammar: adding the 'where' keyword, which would work as follows:

whereexpr : expr 'where' NAME '=' expr

On Tue, Jul 20, 2010 at 10:56 PM, Chris Rebert <pyideas at rebertia.com> wrote:

On Tue, Jul 20, 2010 at 7:50 PM, Alex Light <scialexlight at gmail.com> wrote: > Carl M. johnson wrote: >>2.) What happens in this case: >> >>x = y given: >> return "???" >> >>Do we just disallow return inside a given? If so, how would the parser >>know to allow you to do a def inside a given? > i think so because unless i am misunderstanding something the only allowed > expressions > in a 'given' block would be of the type: > avariable = anexpression

Incorrect. Yes, you are misunderstanding: On Tue, Jul 20, 2010 at 3:13 PM, Nick Coghlan <ncoghlan at gmail.com> wrote: > On Wed, Jul 21, 2010 at 6:13 AM, Alex Light <scialexlight at gmail.com> wrote: >> i would use as because this whole where clause acts very similarly to a >> context manager in that it sets a variable to a value for a small block > > No, the idea is for the indented suite to be a perfectly normal suite > of Python code. We want to be able to define functions, classes, etc > in there. Inventing a new mini-language specifically for these clauses > would be a bad idea (and make them unnecessarily hard to understand) > Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia Did you not read Nick's reply yet when you wrote this, or...? Cheers, Chris -- http://blog.rebertia.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-ideas/attachments/20100721/25aac99a/attachment.html>

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