(*){T<:AbstractFloat}(x::T, y::Vector{T}) should work

[JeffreySarnoff]

# this works
1.5 * [1,0, 2.0]
# this does not
import Base:(*)
immutable FP <: AbstractFloat
   val::Float64
end
(*)(a::FP, b::FP) = FP(a.val * b.val)
afp=FP(1.5); fps=[FP(1.0),FP(2.0)];
afp * fps

There should be fallback definitions that support arithmetic functions where the type of the args is AbstractFloat (or maybe Real) and one or both args is a Vector (or an Array) of the same type, where the arithmetic operator is supported for two elements of that type.

[KristofferC]

Make FP <: AbstractFloat or Number and it works.

[JeffreySarnoff]

I left out the supertype -- edited above.

this error occurs

julia> immutable FP <: AbstractFloat
          val::Float64
       end

julia> import Base:*
julia> (*)(a::FP, b::FP) = FP(a.val * b.val)
* (generic function with 151 methods)

julia> afp=FP(1.5); fps=[FP(1.0),FP(2.0)];

julia> afp * fps
ERROR: MethodError: Cannot `convert` an object of type Int64 to an object of type FP
This may have arisen from a call to the constructor FP(...),
since type constructors fall back to convert methods.
 in promote_op(::Base.#.*, ::Type{FP}, ::Type{FP}) at ./number.jl:73
 in .*(::FP, ::Array{FP,1}) at ./arraymath.jl:71
 in *(::FP, ::Array{FP,1}) at ./abstractarraymath.jl:54
 in eval(::Module, ::Any) at ./boot.jl:234
 in macro expansion at ./REPL.jl:92 [inlined]
 in (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at ./event.jl:46

version 0.5-

[yuyichao]

Basically dup of #17314

[JeffreySarnoff]

I may be missing the core of #17314. Importing Base:one and defining one(::Type{FP}) = FP(1.0) and similarly defining one(x::FP) does not do anything to resolve the error.

[yuyichao]

julia> immutable FP <: AbstractFloat
           val::Float64
       end

julia> import Base: *

julia> *(a::FP, b::FP) = FP(a.val * b.val)
* (generic function with 151 methods)

julia> Base.one(::Type{FP}) = FP(1.0)

julia> afp = FP(1.5); fps = [FP(1.0), FP(2.0)]
2-element Array{FP,1}:
 FP(1.0)
 FP(2.0)

julia> afp * fps
2-element Array{FP,1}:
 FP(1.5)
 FP(3.0)

#265

[JeffreySarnoff]

fancy that -- thank you,