Re: [boost] Re: Automata builder -- interface

From: Douglas Gregor (gregod_at_[hidden])
Date: 2001-05-31 13:05:21

On Thursday 31 May 2001 01:44 pm, you wrote:
[snip]
>
> OK.  But now I'm wondering whether |= is a good idea.  For example:
>
>    ChLit<> a('a');
>    ChLit<> b('b');
>    Rule<> As_b = b;
>    As_b |= a>>A;
>
> Does the final value of As_b represent the following BNF:
>
>   As_b ::= 'a' As_b | 'b'
>
> Or the following:
>
>    As_b ::= 'a' 'b' | 'b'
>
> ?

The first one. (E)BNF is declarative, not imperative, so any nonterminal in 
the right-hand side of a production should be seen as a pointer or reference 
to that nonterminal.

Spirit's syntax & semantics coincide quite nicely with the theory.

        Doug