Jack Jansen wrote:
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".
I am a bit wary about all those syntax details. Actually i try to focus on which events an 'execution monitor' should handle and how it interacts. The problem is that talking about new semantics immeditately brings up the question of syntax and then everybody discusses syntax.
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():
Yes, but names are important and exec autoclose with f1=open(inputfn): ... is not that hard to read and understand. I'd even dare to say it's easier than understanding metaclasses :-) Also today 'exec' is hardly ever needed and so reinterpreting it in the long run might be viable. "Oh yes, i forgot to tell, you can also pass it a string or a code object ..."
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
Isn't that a road to macros? :-) I don't know but it sure reduces readability and it looks like cheating. we don't want to introduce new keywords, anyway. To me it is not only a matter of 'syntax' problems or beeing backward-incompatible but the real problem is the number of concepts and constructs you have to remember, to understand, to use and to teach. holger