Re: [Patch] Let ordinary escaping in POSIX regex be valid
On Fri, Sep 27, 2013 at 4:30 PM, Paolo Carlini paolo.carl...@oracle.com wrote: Nah, only double check that the testcase you are un-xfail-ing uses -std=gnu++11, otherwise will not pass ;) Committed :) Thanks! -- Tim Shen
Re: [Patch] Let ordinary escaping in POSIX regex be valid
On 27 September 2013 03:15, Tim Shen wrote: POSIX ERE says that escaping an ordinary char, say R\n is not permitted, because 'n' is not a special char. However, they also say that : Implementations are permitted to extend the language to allow these. Conforming applications cannot use such constructs. So let's support it not to make users surprised. Booted and tested under -m32 and -m64 I'm wondering whether we want to have a stricter mode that doesn't allow them, to help users avoid creating non-portable programs. We could check the value of the preprocessor macro __STRICT_ANSI__, which is set by -std=c++11 but not by -std=gnu++11, although that's not really the right flag. We want something more like the GNU shell utils' POSIXLY_CORRECT.
Re: [Patch] Let ordinary escaping in POSIX regex be valid
On 9/27/13 4:34 AM, Jonathan Wakely wrote: On 27 September 2013 03:15, Tim Shen wrote: POSIX ERE says that escaping an ordinary char, say R\n is not permitted, because 'n' is not a special char. However, they also say that : Implementations are permitted to extend the language to allow these. Conforming applications cannot use such constructs. So let's support it not to make users surprised. Booted and tested under -m32 and -m64 I'm wondering whether we want to have a stricter mode that doesn't allow them, to help users avoid creating non-portable programs. We could check the value of the preprocessor macro __STRICT_ANSI__, which is set by -std=c++11 but not by -std=gnu++11, although that's not really the right flag. We want something more like the GNU shell utils' POSIXLY_CORRECT. Indeed. I think that for now __STRICT_ANSI__ can do, it's important to manage to accept those otherwise, as we discovered yesterday, we easily reject quite a few rather sensible regex users can write or find in examples: this started when Tim, upon my suggestion, tried the examples in the new edition of Nicolai Josuttis book and found in one those an escaped closed curly bracket (note, closed, open are definitely fine), which apparently most of the other implementations do not reject. Paolo.
Re: [Patch] Let ordinary escaping in POSIX regex be valid
On 27 September 2013 13:32, Paolo Carlini wrote:
On 9/27/13 4:34 AM, Jonathan Wakely wrote:
On 27 September 2013 03:15, Tim Shen wrote:
POSIX ERE says that escaping an ordinary char, say R\n is not
permitted, because 'n' is not a special char. However, they also say
that : Implementations are permitted to extend the language to allow
these. Conforming applications cannot use such constructs.
So let's support it not to make users surprised.
Booted and tested under -m32 and -m64
I'm wondering whether we want to have a stricter mode that doesn't
allow them, to help users avoid creating non-portable programs. We
could check the value of the preprocessor macro __STRICT_ANSI__, which
is set by -std=c++11 but not by -std=gnu++11, although that's not
really the right flag. We want something more like the GNU shell
utils' POSIXLY_CORRECT.
Indeed. I think that for now __STRICT_ANSI__ can do, it's important to
manage to accept those otherwise, as we discovered yesterday, we easily
reject quite a few rather sensible regex users can write or find in
examples: this started when Tim, upon my suggestion, tried the examples in
the new edition of Nicolai Josuttis book and found in one those an escaped
closed curly bracket (note, closed, open are definitely fine), which
apparently most of the other implementations do not reject.
Ah I see. I definitely agree it's good to accept that instead of
being unnecessarily strict, but other people will want the option of
strict conformance, so I think we can please everyone with something
like:
else
{
#ifdef __STRICT_ANSI__
__throw_regex_error(regex_constants::error_escape);
#else
_M_token = _S_token_ord_char;
_M_value.assign(1, __c);
#endif
}
Re: [Patch] Let ordinary escaping in POSIX regex be valid
On Fri, Sep 27, 2013 at 9:37 AM, Jonathan Wakely jwakely@gmail.com wrote:
Ah I see. I definitely agree it's good to accept that instead of
being unnecessarily strict, but other people will want the option of
strict conformance, so I think we can please everyone with something
like:
else
{
#ifdef __STRICT_ANSI__
__throw_regex_error(regex_constants::error_escape);
#else
_M_token = _S_token_ord_char;
_M_value.assign(1, __c);
#endif
}
Sorry for late .
Do I need to bootstrap again?
--
Tim Shen
a.patch
Description: Binary data
Re: [Patch] Let ordinary escaping in POSIX regex be valid
Hi Tim Shen timshe...@gmail.com ha scritto: Do I need to bootstrap again? Nah, only double check that the testcase you are un-xfail-ing uses -std=gnu++11, otherwise will not pass ;) Paolo
[Patch] Let ordinary escaping in POSIX regex be valid
POSIX ERE says that escaping an ordinary char, say R\n is not permitted, because 'n' is not a special char. However, they also say that : Implementations are permitted to extend the language to allow these. Conforming applications cannot use such constructs. So let's support it not to make users surprised. Booted and tested under -m32 and -m64 Thanks! -- Tim Shen a.patch Description: Binary data
