Larry Evans wrote:
On 03/17/08 23:45, Larry Evans wrote:
On 03/17/08 17:55, Eric Niebler wrote:
Larry Evans wrote:
Me too! I couldn't tell from your email -- what are you me too-ing? flattening a sequence of binary operators into one list with a tag indicating the operator to be applied between elements in the list.
See my reply to Markus. Use proto::flatten() and proto::unpack_expr().
And also the means for simplifying an expression somewhat like described by Markus:
I want to detect simultaneous occurences of x and -x and have them dropped from the typelist of my sum.
Use case1:
translating a grammar expression:
x | x
to:
x
Use case2:
Step 1: translating grammar expression: A | B to an expression representing if it can derive empty string: empty<A> | empty<B> which, if A is a the epsilon symbol then emptt<A> == true_ and the whole expression simplifies to:
true_
These are domain-specific use cases. The code for that belongs in your DSEL, not in Proto. -- Eric Niebler Boost Consulting www.boost-consulting.com