"Michael Foord" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> It worries me that there might be a valid expression allowed here that I
> haven't thought of. My current rules allow anything that looks like
> ``(a, [b, c, (d, e)], f)`` - any nested identifier list. Would anything
Guido van Rossum wrote:
> This is probably because we have a similar ambiguity in assignments:
> the grammar says something like
>
> exprlist ('=' exprlist)*
>
> but what is actually desired is
>
> (varlist '=')* exprlist
>
> Unfortunately the latter is not LL1 so we lie to the parser and tell
On 4/24/06, Michael Foord <[EMAIL PROTECTED]> wrote:
> Hello all,
>
> I'm working on a parser for part of the Python language (expressions but
> not statements basically). I'm using PLY to generate the parser and it's
> mostly done.
>
> I've hit on what looks like a fundamental ambiguity in the Pyt
This is probably because we have a similar ambiguity in assignments:
the grammar says something like
exprlist ('=' exprlist)*
but what is actually desired is
(varlist '=')* exprlist
Unfortunately the latter is not LL1 so we lie to the parser and tell
it the first form, and then in the code
[EMAIL PROTECTED] wrote:
> Michael> I've hit on what looks like a fundamental ambiguity in the
> Michael> Python grammar which is difficult to get round with PLY; and
> Michael> I'm wondering *why* the grammar is defined in this way.
>
> Michael,
>
> You refer to the ref manual document
(oops - should have gone to list)
Guido van Rossum wrote:
> Well, yes, the syntax is supposed to be something like "for varlist in
> testlist". Could you report this as a doc bug (if you found this
> information in the docs)?
>
I think the documentation (which does put expression_list there)
r
Hello all,
I'm working on a parser for part of the Python language (expressions but
not statements basically). I'm using PLY to generate the parser and it's
mostly done.
I've hit on what looks like a fundamental ambiguity in the Python
grammar which is difficult to get round with PLY; and I'm
Michael> I've hit on what looks like a fundamental ambiguity in the
Michael> Python grammar which is difficult to get round with PLY; and
Michael> I'm wondering *why* the grammar is defined in this way.
Michael,
You refer to the ref manual documentation:
Michael> List displays (
Well, yes, the syntax is supposed to be something like "for varlist in
testlist". Could you report this as a doc bug (if you found this
information in the docs)?
On 4/24/06, Michael Foord <[EMAIL PROTECTED]> wrote:
> Hello all,
>
> I'm working on a parser for part of the Python language (expressio
Hello all,
I'm working on a parser for part of the Python language (expressions but
not statements basically). I'm using PLY to generate the parser and it's
mostly done.
I've hit on what looks like a fundamental ambiguity in the Python
grammar which is difficult to get round with PLY; and I'm won
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