"Nick Coghlan" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED]
GvR has commented that he want to get rid of the lambda keyword for Python 3.0. Getting rid of lambda seems like a worthy goal, but I'd prefer to see it dropped in favour of a different syntax, rather than completely losing the ability to have anonymous functions.
Anyway, I'm looking for feedback on a def-based syntax that came up in a recent c.l.p discussion:
http://boredomandlaziness.skystorm.net/2004/12/anonymous-functions-in-python.html
Cheers, Nick.
I think it's rather baroque, and I agree with Paul Ruben that it needs multiple statement capability.
The syntax I prefer (and I don't know if it's actually been
suggested before) is to use braces, that is { and }.In other words, an anonymous function looks like:
{p1, p2, p3 |
stmt1
stmt2
}There are two reasons for using braces. One is that it's the common syntax for blocks in a large number of languages. The other is that it should be relatively easy to disambiguate from dictionary literals, which are the only other current use of braces.
The parameter list is optional, as is the bar ending the list. The reason for the bar instead of a colon is to help the parser in the case of a single parameter, which would look like the beginning of a dictionary literal. If the parser doesn't need the help, then a colon would be more consistent, hence better.
A second issue is indentation. I'd set the indentation boundary wherever the _second_ line of the construct starts, as long as it's to the right of the prior indentation boundary. The unfortunate part of this, and one of the major stumbling blocks, is that it might take some significant reconceptualizing of the lexer and parser, which currently isn't set up to shift from expression back to statement mode and then return to expression mode.
John Roth
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Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
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