fix #28 (#29)

putianyi889 · Dec 23, 2024 · 93e155d · 93e155d
1 parent 58035db
commit 93e155d
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diff --git a/docs/src/index.md b/docs/src/index.md
@@ -57,3 +57,17 @@ where `some` can be `el`, `base` and `precision`.
   ```@repl 1
   precisiontype(convert_precisiontype(Int128, Int8(1)//Int8(2)))
   ```
+
+## Notable behaviours
+
+### Ranges
+Ranges in Julia are not consistently processed:
+```@repl 1
+r = StepRange(1,1,5)
+Float64.(r) |> typeof
+map(Float64,r) |> typeof
+```
+We adapt `_to_eltype` to the return type of `Base.map`:
+```@repl 1
+_to_eltype(Float64, StepRange{Int,Int})
+```
diff --git a/src/EltypeExtensions.jl b/src/EltypeExtensions.jl
@@ -39,7 +39,6 @@ $(repr("text/plain", Matrix{Float64}))
 ```
 """
 convert_eltype(::Type{T}, A::S) where {T,S} = convert(_to_eltype(T, S), A)
-convert_eltype(::Type{T}, A::AbstractArray) where T = convert(AbstractArray{T}, A)
 convert_eltype(::Type{T}, A::AbstractRange) where T = map(T, A)
 convert_eltype(::Type{T}, A::AbstractUnitRange) where T<:Integer = convert(AbstractUnitRange{T}, A)
 convert_eltype(::Type{T}, A::Tuple) where T = convert.(T, A)
@@ -86,9 +85,12 @@ _to_eltype(::Type{T}, ::Type{<:CartesianIndices}) where T = Array{T}
 
 @static if VERSION >= v"1.7"
     _to_eltype(::Type{T}, ::Type{<:StepRangeLen}) where T<:Real = StepRangeLen{T,_to_eltype(T,TwicePrecision),_to_eltype(T,TwicePrecision),Int}
+    _to_eltype(::Type{T}, ::Type{<:StepRange}) where T<:AbstractFloat = StepRangeLen{T,_to_eltype(T,TwicePrecision),_to_eltype(T,TwicePrecision),Int}
 else
     _to_eltype(::Type{T}, ::Type{<:StepRangeLen}) where T<:Real = StepRangeLen{T,_to_eltype(T,TwicePrecision),_to_eltype(T,TwicePrecision)}
+    _to_eltype(::Type{T}, ::Type{<:StepRange}) where {T<:AbstractFloat} = StepRangeLen{T,_to_eltype(T,TwicePrecision),_to_eltype(T,TwicePrecision)}
 end
+_to_eltype(::Type{T}, ::Type{<:StepRange}) where {T<:Real} = StepRange{T,T} # technically, it is better to preserve the step type. The current implementation follows from `Base.map(::Type{T}, r::StepRange) where {T<:Real}`.
 _to_eltype(::Type{T}, ::Type{<:UnitRange}) where T<:Integer = UnitRange{T}
 _to_eltype(::Type{T}, ::Type{<:UnitRange}) where T<:Real = _to_eltype(T, StepRangeLen)
 

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -30,6 +30,10 @@ end
     testelconvert(Int8, r)
     testelconvert(Float64, r)
 
+    r = 1:1:5
+    testelconvert(Int8, r)
+    testelconvert(Float64, r)
+
     inds = CartesianIndex(1,1):CartesianIndex(3,3)
     testelconvert(CartesianIndex{2}, inds)
     testelconvert(Tuple, inds)