Move ranges from ArrayInterface to Static (#88)

* Move ranges from ArrayInterface to Static
* Use breaking version so that ArrayInterface ranges are compatible
* static_promote for ranges
* Add `IntType` union and function
This replaces the concept of "canonical" integers in ArrayInterface so
we can also move that functionality here.

Author: Tokazama

Project.toml

@@ -1,7 +1,7 @@
 name = "Static"
 uuid = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
 authors = ["chriselrod", "ChrisRackauckas", "Tokazama"]
-version = "0.7.8"
+version = "0.8"
 
 [deps]
 IfElse = "615f187c-cbe4-4ef1-ba3b-2fcf58d6d173"

src/Static.jl

@@ -61,6 +61,16 @@ struct StaticInt{N} <: StaticInteger{N}
     StaticInt(::Val{N}) where {N} = StaticInt(N)
 end
 
+"""
+    IntType(x::Integer) -> Union{Int,StaticInt}
+
+`IntType` is a union of `Int` and `StaticInt`. As a function, it ensures that `x` one of the
+two.
+"""
+const IntType = Union{StaticInt, Int}
+IntType(x::Integer) = Int(x)
+IntType(@nospecialize x::Union{Int, StaticInt}) = x
+
 include("float.jl")
 
 const StaticNumber{N} = Union{StaticInt{N}, StaticBool{N}, StaticFloat64{N}}
@@ -260,6 +270,36 @@ _static_promote(::Nothing, ::Nothing) = nothing
 _static_promote(x, ::Nothing) = x
 _static_promote(::Nothing, y) = y
 
+"""
+    static_promote(x::AbstractRange{<:Integer}, y::AbstractRange{<:Integer})
+
+A type stable method for combining two equal ranges into a new range that preserves static
+parameters. Throws an error if `x != y`.
+
+# Examples
+
+```julia
+julia> static_promote(static(1):10, 1:static(10))
+static(1):static(10)
+
+julia> static_promote(1:2:9, static(1):static(2):static(9))
+static(1):static(2):static(9)
+```
+"""
+Base.@propagate_inbounds @inline function static_promote(x::AbstractUnitRange{<:Integer},
+                                                         y::AbstractUnitRange{<:Integer})
+    fst = static_promote(static_first(x), static_first(y))
+    lst = static_promote(static_last(x), static_last(y))
+    return OptionallyStaticUnitRange(fst, lst)
+end
+Base.@propagate_inbounds @inline function static_promote(x::AbstractRange{<:Integer},
+                                                         y::AbstractRange{<:Integer})
+    fst = static_promote(static_first(x), static_first(y))
+    stp = static_promote(static_step(x), static_step(y))
+    lst = static_promote(static_last(x), static_last(y))
+    return _OptionallyStaticStepRange(fst, stp, lst)
+end
+
 Base.@propagate_inbounds function _promote_shape(a::Tuple{A, Vararg{Any}},
                                                  b::Tuple{B, Vararg{Any}}) where {A, B}
     (static_promote(getfield(a, 1), getfield(b, 1)),
@@ -879,4 +919,6 @@ function Base.show(io::IO, m::MIME"text/plain", @nospecialize(x::NDIndex))
     nothing
 end
 
+include("ranges.jl")
+
 end