macros to parse code to use different types

parsetypes.jl

using MacroTools, Base.Test

"@parsetype T ex
replace all numeric literals that are supertypes of `T` with type `T`"
macro parsetype(Tsym, ex)
    T=getfield(Main, Tsym)
    ST=parsesuper(T)
    parsetype(T, ST, ex)
end

"@parsetype (T1,T2,..) ex
as @parsetype for each type in first argument, which must be a tuple"
macro parsetypes(tuple_ex, ex)
    for Tsym in tuple_ex.args
        T=getfield(Main, Tsym)
        ST=parsesuper(T)
        ex = parsetype(T,ST,ex)
    end
    ex
end


parsesuper(::Type{T}) where T= supertype(T)
parsesuper(::Type{T<:Integer}) where T = Integer


function parsetype(::Type{T},::Type{ST},ex::Expr) where {ST,T<:ST}
    MacroTools.postwalk(x->typeof(x)<:ST ? T(x) : x, ex)
end

"@parsefunction f T ex
places T as the first argument of all calls to `f`
doesn't yet check if it already has a type as first argument
or even check if `f` matches `fin`"
macro parsefunction(fin,Tsym,ex)
    dump(ex)
    T=getfield(Main, Tsym)
    MacroTools.postwalk(ex) do x
        @capture(x, f_(xs__)) || return x
        return quote $f($Tsym,$(xs...)) end
    end
end

@test 2 == @parsetype Int8 1+1
@test Int8 == typeof(@parsetype Int8 1+1)
@test  2 == @parsetype Float16 1.0+1.0
@test  Float16 == typeof(@parsetype Float16 1.0+1.0)
@test (Float16,Int8) == @parsetypes (Int8,Float16) typeof(1.0),typeof(1)

@test eltype(@parsefunction rand Float32 rand(3,3)) == Float32
@test size(@parsefunction rand Float32 rand(3,3)) == (3,3)