Update ProductSpace constructors with promote/convert (#112)

* Update ProductSpace constructors for more flexibility

* Fix test productspace errortype

* Fix missing Productspace constructor

Author: lkdvos

src/spaces/productspace.jl

@@ -22,12 +22,30 @@ ProductSpace{S}(spaces::Vararg{S}) where {S<:ElementarySpace} = ProductSpace{S}(
 function ProductSpace(spaces::Tuple{S,Vararg{S}}) where {S<:ElementarySpace}
     return ProductSpace{S,length(spaces)}(spaces)
 end
-function ProductSpace(space1::S, rspaces::Vararg{S}) where {S<:ElementarySpace}
+function ProductSpace(space1::ElementarySpace, rspaces::Vararg{ElementarySpace})
     return ProductSpace((space1, rspaces...))
 end
 
 ProductSpace(P::ProductSpace) = P
 
+# constructors with conversion behaviour
+function ProductSpace{S,N}(V::Vararg{ElementarySpace,N}) where {S<:ElementarySpace,N}
+    return ProductSpace{S,N}(V)
+end
+function ProductSpace{S}(V::Vararg{ElementarySpace}) where {S<:ElementarySpace}
+    return ProductSpace{S}(V)
+end
+
+function ProductSpace{S,N}(V::Tuple{Vararg{ElementarySpace,N}}) where {S<:ElementarySpace,N}
+    return ProductSpace{S}(convert.(S, V))
+end
+function ProductSpace{S}(V::Tuple{Vararg{ElementarySpace}}) where {S<:ElementarySpace}
+    return ProductSpace{S}(convert.(S, V))
+end
+function ProductSpace(V::Tuple{ElementarySpace,Vararg{ElementarySpace}})
+    return ProductSpace(promote(V...))
+end
+
 # Corresponding methods
 #-----------------------
 """

test/spaces.jl

@@ -122,7 +122,7 @@ println("------------------------------------")
         # promote_except = ErrorException("promotion of types $(typeof(ℝ^d)) and " *
         #                                 "$(typeof(ℂ^d)) failed to change any arguments")
         # @test_throws promote_except (⊕(ℝ^d, ℂ^d))
-        @test_throws MethodError (⊗(ℝ^d, ℂ^d))
+        @test_throws ErrorException (⊗(ℝ^d, ℂ^d))
         @test @constinferred(⊕(V, V)) == ℂ^(2d)
         @test @constinferred(⊕(V, oneunit(V))) == ℂ^(d + 1)
         @test @constinferred(⊕(V, V, V, V)) == ℂ^(4d)