Support new zeros/ones methods from #19635 (#330)

Author: timholy

README.md

@@ -153,6 +153,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `broadcast` is supported on tuples of the same lengths on 0.5. ([#16986])
 
+* `zeros` and `ones` support an interface the same as `similar` ([#19635])
+
 ## Renamed functions
 
 * `pointer_to_array` and `pointer_to_string` have been replaced with `unsafe_wrap(Array, ...)` and `unsafe_wrap(String, ...)` respectively
@@ -346,3 +348,4 @@ includes this fix. Find the minimum version from there.
 [#20414]: https://github.com/JuliaLang/julia/issues/20414
 [#20418]: https://github.com/JuliaLang/julia/issues/20418
 [#20500]: https://github.com/JuliaLang/julia/issues/20500
+[#19635]: https://github.com/JuliaLang/julia/issues/19635

src/Compat.jl

@@ -1421,6 +1421,17 @@ if VERSION < v"0.6.0-dev.2840"
     IndexStyle(args...) = Base.linearindexing(args...)
 end
 
+if VERSION < v"0.6.0-dev.1653"
+    for (fname, felt) in ((:zeros,:zero), (:ones,:one))
+        @eval begin
+            # allow signature of similar
+            Base.$fname(a::AbstractArray, T::Type, dims::Tuple) = fill!(similar(a, T, dims), $felt(T))
+            Base.$fname(a::AbstractArray, T::Type, dims...) = fill!(similar(a,T,dims...), $felt(T))
+            Base.$fname(a::AbstractArray, T::Type=eltype(a)) = fill!(similar(a,T), $felt(T))
+        end
+    end
+end
+
 # https://github.com/JuliaLang/julia/pull/20203
 if VERSION < v"0.6.0-dev.2283"
     # not exported

test/runtests.jl

@@ -1773,9 +1773,22 @@ let a = CompatArray.CartesianArray(rand(2,3)), b = CompatArray.LinearArray(rand(
     @test IndexStyle(b) === IndexLinear()
 end
 
+for (A,val) in ((zeros(1:5, Float32, 3, 2), 0),
+                (ones(1:5, Float32, 3, 2), 1),
+                (zeros(1:5, Float32, (3, 2)), 0),
+                (ones(1:5, Float32, (3, 2)), 1))
+    @test isa(A, Matrix{Float32}) && size(A) == (3,2) && all(x->x==val, A)
+end
+for (A,val) in ((zeros(1:5, Float32), 0),
+                (ones(1:5, Float32), 1))
+    @test isa(A, Vector{Float32}) && size(A) == (5,) && all(x->x==val, A)
+end
+
 # PR 20203
 @test Compat.readline(IOBuffer("Hello, World!\n")) == "Hello, World!"
 @test Compat.readline(IOBuffer("x\n"), chomp=true) == "x"
 @test Compat.readline(IOBuffer("x\n"), chomp=false) == "x\n"
 
 include("to-be-deprecated.jl")
+
+nothing