Re: [Boost-users] [mpl] trouble with conditionals

Geoffrey Romer writes:

OK, your correction works, but I don't understand why. I thought that omitting the typename ... ::type syntax just creates a null-ary metafunction. For example,

pair, at >

seems to me like it would produce not a pair consisting of a char and an int_, but a pair consisting of a char and a null-ary metafunction which, when applied, produces an int_. Am I missing something?

The 2nd argument to plus above probably isn't what you think. You're passing it a nullary metafunction: at. -- Dave Abrahams Boost Consulting www.boost-consulting.com