Re: [Boost-users] proto: BOOST_PROTO_AUTO

6 Jan 2009

      AMDG

Kim Kuen Tang wrote:
...
Hi Eric,
thank you for your quick response.
It is interesting to see that expression like "Domain( [0,1] )"  is 
not allowed. I think the reason is that such expression cannot be 
transformed in a tree or the transformation is not unique.
But why does the code "proto::display_expr(Domain[1,2]);" produce the 
output:
subscript(
   terminal(domain_tag)
   ,terminal(2)
 )
and not
subscript(
   terminal(domain_tag)
   ,terminal(1)
   ,terminal(2)
 ) ?
The evaluation goes like this:

1, 2 -> 2 --- by the built in comma operator
Domain[2] -> subscript(terminal(domain_tag),terminal(2)) -- by proto's 
operator[]

In Christ,
Steven Watanabe