On 09/27/2013 08:47 PM, Alex Rousskov wrote:
> On 09/27/2013 09:39 AM, Amos Jeffries wrote:
>> On 28/09/2013 3:18 a.m., Tsantilas Christos wrote:
>>> On 09/27/2013 08:23 AM, Alex Rousskov wrote:
>>>> Using approach (2) with flexible RE delimiter, we could write
>>>>
>>>> acl foo url_regex /ends[) (]/
>>>> or
>>>> acl foo url_regex {ends[) (]}
>>>> or
>>>> acl foo url_regex @ends[) (]@
>>>>
>>>> and it will all work without double escaping.
>>>
>>>
>>> Alex, in the "Revised approach to fixing configuration syntax" mail
>>> thread you are proposing to use "regex::" prefix for regular
>>> expressions. This is required for grammar consistency.
>>> This is means that the regex should like :
>>>
>>> acl foo url_regex regex::/ends[) (]/
>>> or
>>> acl foo url_regex regex::{ends[) (]}
>>> or
>>> acl foo url_regex regex::@ends[) (]@
>
> Yes, IF that syntax is adopted.
>
>
>> Okay Alex I think we can agree on that flexible-delimiter syntax to
>> avoid escaping.
>>
>> I also agree with that regex:: prefix.
>>
>> Is there anything else we have been disagreeing on?
>
>
> As far as REs are concerned, we need to decide
>
> 1) Whether we want to support the new regex:: syntax at all or keep
> using spaceless REs as before (at least for now) while reserving the
> regex:: prefix.
>
>
> 2) If we want to support the new regex:: syntax:
>
> 2a) What characters do we allow as RE delimiters? Perl allows virtually
> any non-whitespace character, even #, but we probably want to be more
> restrictive.
Any non whitespace character I think is good choice. Else any
non-alphanumeric, non-whitespace character.
>
> 2b) Do we add support for escaping sequences? As discussed a few emails
> back, that support is necessary if we want to support arbitrary REs,
> which is somewhat important for automated config generators. It is also
> needed for (2c).
Escaping is important. The user will select the delimiters which
requires the less escaping but may he is not able to avoid it:
eg select this one
regex::#A/test/with/one\#and/many/#
instead of this:
regex::/A\/test\/with\/one#and\/many\//
>
> 2c) Do we add support for character sequences so that one can add
> special characters and such? This also requires a form of escaping. For
> example, here are some of the sequences supported by Perl (we do not
> support all of them immediately, of course, but we need to reserve
> \-escape if we want them in the future):
>
>> Sequence Description
>> \t tab (HT, TAB)
>> \n newline (NL)
>> \r return (CR)
>> \f form feed (FF)
>> \b backspace (BS)
>> \a alarm (bell) (BEL)
>> \e escape (ESC)
>> \x{263A} hex char (example: SMILEY)
>> \x1b restricted range hex char (example: ESC)
>> \N{name} named Unicode character or character sequence
>> \N{U+263D} Unicode character (example: FIRST QUARTER MOON)
>> \c[ control char (example: chr(27))
>> \o{23072} octal char (example: SMILEY)
>> \033 restricted range octal char (example: ESC)
>
> We could also try to abuse existing character class [[:class:]] syntax
> for those. For example, we can find and replace [[:squid::octal(32):]]
> sequences with a space character.
Looks good idea to me to support perl syntax ...
>
>
> Note that (2c) applies to "strings" as well, IMO.
>
>
> Alex.
