On 9/27/2010 5:06 PM, David Abrahams wrote:
At Mon, 27 Sep 2010 15:57:49 -0400, Eric Niebler wrote:
I want to say that a SpiritParser is a SpiritNode<plus> OR a SpiritNode<right_shift> OR a SpiritNode<terminal> (the plus and right_shift concepts being recursively defined in terms of SpiritParser,
I showed you how to handle it above.
You showed me (in broken code according to Sebastian) how to define a concept that, AFAICT, is useless.
You're thinking about this the wrong way. Concepts are a rule-based system, and you're approaching them functionally. It's a totally different programming paradigm.
This doesn't help me understand it.
the terminal concept having little more than a value_type typedef and a member), the intersection of all those concepts would have exactly nothing. So I couldn't do anything with it from a constrained context. What have I missed? How is the SpiritParser concept you've defined above supposed to be used?
Heck if I know; it's your library, man! It's empty because I don't know what operations your operator= needs from it.
<shrug> I leave this conversation as I leave every conversation about concepts: just as confused as when I started. I write template libraries and care about error messages. Concepts were billed as a way to improve error messages from template libraries. And yet nobody can tell me how to actually use concepts to implement my libraries and improve error messages. -- Eric Niebler BoostPro Computing http://www.boostpro.com