[Boost-users] [Proto] Extracting types of sub-expression in transform

Hello, i have a DSL where terminal are defined like : terminal< simdproto::_ > What I want is that any binary operator that apply on those terminal should be available only if both lhs and rhs parts have the same underlying type. E.G : simd<float> + simd<float> is ok while (simd<char> + simd<char>)*simd<float> is not ok. How I can enforce this check ? Is having a transform that take an expression and returns the underlying type OR mpl::void_ if an error occurs the good solution ? Thanks in advance -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35