mapslices with dims keyword argument

README.md

@@ -306,6 +306,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 * `something` to get the first argument different from `nothing`, unwrapping those
   of the `Some` type ([#27258]).
 
+* `mapslices` with `dims` keyword argument ([#27828]).
+
 ## Renaming
 
 * `Display` is now `AbstractDisplay` ([#24831]).
@@ -658,3 +660,4 @@ includes this fix. Find the minimum version from there.
 [#27258]: https://github.com/JuliaLang/julia/issues/27258
 [#27298]: https://github.com/JuliaLang/julia/issues/27298
 [#27401]: https://github.com/JuliaLang/julia/issues/27401
+[#27828]: https://github.com/JuliaLang/julia/issues/27828

src/Compat.jl

@@ -1966,6 +1966,12 @@ end
         Base.split(s, splitter; limit=limit, keep=keepempty)
 end
 
+# https://github.com/JuliaLang/julia/pull/27828
+if VERSION < v"0.7.0-beta.73"
+    Base.mapslices(f, A::AbstractArray; dims=error("required keyword argument `dims` missing")) =
+        mapslices(f, A, dims)
+end
+
 include("deprecated.jl")
 
 end # module Compat

test/runtests.jl

@@ -1896,4 +1896,14 @@ let
     @test Compat.split(str, r"\.+:\.+"; limit=3, keepempty=true) == ["a","ba","cba.:.:.dcba.:."]
 end
 
+# 0.7.0-beta.73
+let a = rand(5,5)
+    s = mapslices(sort, a, dims=[1])
+    S = mapslices(sort, a, dims=[2])
+    for i = 1:5
+        @test s[:,i] == sort(a[:,i])
+        @test vec(S[i,:]) == sort(vec(a[i,:]))
+    end
+end
+
 nothing