Re: [boost] [proto] minor issue: unnecessary typedefs _arg*

From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-03-18 19:03:40

AMDG

Markus Werle wrote:
>> <snip>
>>
>> Re: the _argN transforms ...
>>     
>>> I assumed they were generated by a macro until BOOST_PROTO_MAX_ARITY ...
>>> I was preaching against that (inexistent?) macro.
>>> Now I took a look at proto_fwd.hpp and found they are made by hand
>>> and stop at 9. So now I really have a problem:
>>> what happens if I need an arity of 120?
>>>       
>> Ha! I imaging you'll need longer than the heat death of the universe to
>> compile your program, 
>>     

If you have an arity grater than 120 you should be using sequence 
algorithms like fold.
_arg1, _arg2, &c. work fine up to a certain point, but I would run 
screaming in terror if I
saw a program that hard coded _arg412 e.g.

struct EvilTransform :
    or_<
        when_<nary_expr<tag::plus, vararg<_> >, _make_plus(_arg231, 
_arg125) >,
        when_<nary_expr<tag::minus, vararg<_> >, _make_minus(_arg34, 
_arg371) >,
        otherwise<_make_modulus(_arg19, _arg98)>
    >
{};

In Christ,
Steven Watanabe