Re: [boost] [metaparse] Review period starts May 25th and ends June 7th - ongoing

Subject: Re: [boost] [metaparse] Review period starts May 25th and ends June 7th - ongoing
From: Abel Sinkovics (abel_at_[hidden])
Date: 2015-06-09 02:22:41

Hi Roland,

On 2015-06-09 07:03, Roland Bock wrote:
>> What might be done based on your portable static assertion approach 
>> is adding a static method to these error classes representing the 
>> compilation errors to "static assert themselves" with better error 
>> messages. My concern about this is loosing the details of the error 
>> (position in the parsed text, the range boundaries and the index in 
>> case of an out of range error, etc). I'll check if "static assert 
>> yourself" can be done without loosing that information. 
> I had similar concerns at the beginning. It turned out (at least in my
> case) that the "lost information"
>
>    * might be relevant for the developer of the library
>    * was just hiding the relevant things from the user
>
> Whether the same is true for Metaparse, I don't know.
In case of Metaparse the information lost there is important for the 
users of the parsers. It has the answers to questions like:
- where (in the DSL script) is the error coming from? (column, maybe 
line number)
- information that is a template argument of a parser combinator. For 
example: when the parser finds a different character than what was 
expected in the DSL script, what was the expected character? eg. when 
the parser is parsing "()" or "[]" pairs and is waiting for the closing 
element, etc. In those cases the expected characters are template 
arguments, not hard-coded values of the parsers (and parser combinators) 
the library offers. And they should be part of the error report.

Regards,
   Ábel