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Groups > comp.compilers > #1522
| From | Kaz Kylheku <kaz@kylheku.com> |
|---|---|
| Newsgroups | comp.compilers |
| Subject | Re: Grammar with low-precedence postfix operator? |
| Date | 2015-02-09 01:24 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <15-02-020@comp.compilers> (permalink) |
| References | <15-02-006@comp.compilers> <15-02-018@comp.compilers> |
On 2015-02-08, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>> term
>> : INT
>> | '(' expr ')' //parentheses
>> | <assoc=right> term '^' term //exponentiation
>> | term term //implicit multiplication
>> ;
>
>> expr
>> : term
>> | ('+' | '-') expr //unary plus/minus
>> | expr ('/' | '*') expr //division and explicit multiplication
>> | expr ('+' | '-') expr //addition/subtraction
>> | expr '++' //increment
>> ;
>
> This last production rule is wrong: "expr ++" should produce a "term", not
> an "expr".
If that is so, then ++ shall not have the desired low precedence.
For instance a ^ b ++ be parsed as the exponentiation of two terms,
a and b++, not as ++ applied to the expression a ^ b, as desired.
[Oops, looks like you're right. -John]
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Grammar with low-precedence postfix operator? Robert Jacobson <rljacobson@gmail.com> - 2015-02-05 13:27 -0500
Re: Grammar with low-precedence postfix operator? Kaz Kylheku <kaz@kylheku.com> - 2015-02-05 21:10 +0000
Re: Grammar with low-precedence postfix operator? Robert Jacobson <rljacobson@gmail.com> - 2015-02-07 10:30 -0800
Re: Grammar with low-precedence postfix operator? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-07 11:27 +0000
Re: Grammar with low-precedence postfix operator? jgk@panix.com (Joe keane) - 2015-02-10 21:03 +0000
Re: Grammar with low-precedence postfix operator? Kaz Kylheku <kaz@kylheku.com> - 2015-02-11 02:19 +0000
Re: Grammar with low-precedence postfix operator? Stefan Monnier <monnier@iro.umontreal.ca> - 2015-02-08 12:34 -0500
Re: Grammar with low-precedence postfix operator? Kaz Kylheku <kaz@kylheku.com> - 2015-02-09 01:24 +0000
Re: Grammar with low-precedence postfix operator? Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2015-02-09 08:05 +0100
Re: Grammar with low-precedence postfix operator? Robert Jacobson <rljacobson@gmail.com> - 2015-02-21 12:55 -0800
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