On Tuesday, Feb 4, 2003, at 12:54 Europe/Amsterdam, holger krekel wrote:
exec expr [with params]: suite
Gut reaction: ugh!
then i guess you rather prefer new keywords. I thought that there is a general reluctance to introduce new keywords *and* many people dislike 'exec' for its existence.
I agree with Michael's "Ugh!". And actually I extend the "Ugh!" to Guido's proposal of "expr [= expr] [lambda]: suite". While I think that the reluctance to introduce new keywords is a good thing in principle it shouldn't go at the expense of the clarity of the language. In other words, if there is a clear construct that doesn't require a new keyword (cf. import as) that is a good thing, but if the clarity of Python would be compromised then I think we should bite the bullet and add a new keyword. We should think of people who come fresh to Python in three years time. What "if" does and what the parameters are is immediately clear. Same for "for". Same for "class", "def", assignments and what-have-you. And then suddenly they come across foo(): ... or exec foo(): ... The only construct I can think of that would give the user an idea of what was happening is "with expr [= expr]". And even that will become ugly once you want to support both thunks with a new scope and parameters, and thunks in the existing scope. Last week I made a suggestion that was completely ignored, so let me try again (i.e. if everyone thinks it's silly please shoot it down in stead of ignoring it:-): how about adding a meta-keyword that would be used to turn an identifier into a keyword. For sake of the example let's use "keyword" as the meta-keyword, although that's a bad choice, probably. Here's how it would be used: if we decide to go with "with" as the thunk-keyword what happens is that in Python 2.4 you would have to type it as keyword(with) expr: suite or, alternatively, do something like "from future import with_keyword". In 2.4, using "with" as an identifier would give a FutureWarning. In Python 2.5 "with" would become a reserved word, but keyword(with) would still continue to work. Whether the latter is for one release (with accompanying FutureWarning) or for all eternity is open to discussion. -- Jack Jansen, <Jack.Jansen@cwi.nl>, http://www.cwi.nl/~jack If I can't dance I don't want to be part of your revolution -- Emma Goldman