Re: [boost] Re: Formal Review: The Spirit Parser Framework.

From: Beman Dawes (bdawes_at_[hidden])
Date: 2002-10-15 13:26:03

At 09:45 PM 10/14/2002, Joel de Guzman wrote:

 >>    * Can easily parse local contradictions (always AB,
 >>      except in certain expressions its BA).
 >
 >If I understand correctly, you mean special cases?
 >Correct me if I'm wrong.
 >
 >The framework is malleable to special cases. There are exciting
 >possibilities with dynamic parsing. Here's an example:
 >
 >    bool flag;
 >    r =
 >        if_p(flag)
 >        [
 >            parse_it_this_way
 >        ]
 >        .else_
 >        [
 >            parse_it_that_way
 >        ]
 >
 >.. if(c)[p1].else_[p2]
 >    parse p1 if c evaluates to true, else parse p2.

Yes, that is exactly what I meant. If what is being parsed is something 
like a programming language, the designers usually try to avoid special 
cases.  But if the input to be parsed comes from material extracted from 
newspapers, for example, is is often shot through with special cases.  Glad 
to hear Spirit can deal with special cases easily.

--Beman