Lower [:] as Colon instead of a range

Cherry-picked from a squashed-and-split version of #9150 to exclude the bigger change of returning views from indexing with UnitRanges.

Conflicts:
	base/abstractarray.jl
	base/multidimensional.jl
	src/julia-syntax.scm

base/abstractarray.jl

@@ -114,12 +114,12 @@ linearindexing{A<:Array}(::Type{A}) = LinearFast()
 linearindexing{A<:Range}(::Type{A}) = LinearFast()
 
 ## Bounds checking ##
-checkbounds(sz::Int, ::Colon) = nothing
 checkbounds(sz::Int, i::Int) = 1 <= i <= sz || throw(BoundsError())
 checkbounds(sz::Int, i::Real) = checkbounds(sz, to_index(i))
 checkbounds(sz::Int, I::AbstractVector{Bool}) = length(I) == sz || throw(BoundsError())
 checkbounds(sz::Int, r::Range{Int}) = isempty(r) || (minimum(r) >= 1 && maximum(r) <= sz) || throw(BoundsError())
 checkbounds{T<:Real}(sz::Int, r::Range{T}) = checkbounds(sz, to_index(r))
+checkbounds(sc::Int, ::Colon) = true
 
 function checkbounds{T <: Real}(sz::Int, I::AbstractArray{T})
     for i in I
@@ -131,17 +131,17 @@ checkbounds(A::AbstractArray, I::AbstractArray{Bool}) = size(A) == size(I) || th
 
 checkbounds(A::AbstractArray, I) = checkbounds(length(A), I)
 
-function checkbounds(A::AbstractMatrix, I::Union(Real,Colon,AbstractArray), J::Union(Real,Colon,AbstractArray))
+function checkbounds(A::AbstractMatrix, I::Union(Real,AbstractArray,Colon), J::Union(Real,AbstractArray,Colon))
     checkbounds(size(A,1), I)
     checkbounds(size(A,2), J)
 end
 
-function checkbounds(A::AbstractArray, I::Union(Real,Colon,AbstractArray), J::Union(Real,Colon,AbstractArray))
+function checkbounds(A::AbstractArray, I::Union(Real,AbstractArray,Colon), J::Union(Real,AbstractArray,Colon))
     checkbounds(size(A,1), I)
     checkbounds(trailingsize(A,2), J)
 end
 
-function checkbounds(A::AbstractArray, I::Union(Real,Colon,AbstractArray)...)
+function checkbounds(A::AbstractArray, I::Union(Real,AbstractArray,Colon)...)
     n = length(I)
     if n > 0
         for dim = 1:(n-1)

base/array.jl

@@ -392,6 +392,7 @@ function setindex!{T<:Real}(A::Array, X::AbstractArray, I::AbstractVector{T})
     return A
 end
 
+setindex!(A::Array, x, I::Colon) = setindex!(A, x, 1:length(x))
 
 # logical indexing
 # (when the indexing is provided as an Array{Bool} or a BitArray we can be

base/multidimensional.jl

@@ -236,7 +236,7 @@ _getindex(A, I::(Union(Int,AbstractVector)...)) =
 
 # The stagedfunction here is just to work around the performance hit
 # of splatting
-stagedfunction getindex(A::Array, I::Union(Real,AbstractVector)...)
+stagedfunction getindex(A::Array, I::Union(Real,AbstractVector,Colon)...)
     N = length(I)
     Isplat = Expr[:(I[$d]) for d = 1:N]
     quote
@@ -246,7 +246,7 @@ stagedfunction getindex(A::Array, I::Union(Real,AbstractVector)...)
 end
 
 # Also a safe version of getindex!
-stagedfunction getindex!(dest, src, I::Union(Real,AbstractVector)...)
+stagedfunction getindex!(dest, src, I::Union(Real,AbstractVector,Colon)...)
     N = length(I)
     Isplat = Expr[:(I[$d]) for d = 1:N]
     Jsplat = Expr[:(to_index(I[$d])) for d = 1:N]
@@ -257,7 +257,7 @@ stagedfunction getindex!(dest, src, I::Union(Real,AbstractVector)...)
 end
 
 
-stagedfunction setindex!(A::Array, x, J::Union(Real,AbstractArray)...)
+stagedfunction setindex!(A::Array, x, J::Union(Real,AbstractArray,Colon)...)
     N = length(J)
     if x<:AbstractArray
         ex=quote

base/range.jl

@@ -67,6 +67,8 @@ immutable UnitRange{T<:Real} <: OrdinalRange{T,Int}
 end
 UnitRange{T<:Real}(start::T, stop::T) = UnitRange{T}(start, stop)
 
+colon() = Colon()
+
 colon(a::Real, b::Real) = colon(promote(a,b)...)
 
 colon{T<:Real}(start::T, stop::T) = UnitRange{T}(start, stop)

src/julia-syntax.scm

@@ -332,7 +332,7 @@
 
 ; translate index x from colons to ranges
 (define (expand-index-colon x)
-  (cond ((eq? x ':) `(call colon 1 end))
+  (cond ((eq? x ':) `(call colon))
         ((and (pair? x)
               (eq? (car x) ':))
          (cond ((length= x 3)