squeeze is now dropdims (#618)

* squeeze is now dropdims

`squeeze` was renamed `dropdims` in [#28303](JuliaLang/julia#28303)

Fixes #617

* Support dropdims for dev versions where squeeze had KW arg

Also, remove README information about squeeze support, since dropdims is the
preferred replacement.

* Export dropdims

README.md

@@ -292,8 +292,6 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `selectdim` to obtain a view of an array with a specified index for a specified dimension ([#26009]).
 
-* `squeeze` with `dims` as keyword argument ([#26660]).
-
 * Single-argument `permutedims(x)` for matrices and vectors ([#24839]).
 
 * `fetch` for `Task`s ([#25940]).
@@ -434,6 +432,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `realmin` and `realmax` are now `floatmin` and `floatmax` ([#28302])
 
+* `squeeze` is now `dropdims` ([#28303], [#26660]).
+
 ## New macros
 
 * `@__DIR__` has been added ([#18380])
@@ -671,3 +671,4 @@ includes this fix. Find the minimum version from there.
 [#27828]: https://github.com/JuliaLang/julia/issues/27828
 [#27834]: https://github.com/JuliaLang/julia/issues/27834
 [#28302]: https://github.com/JuliaLang/julia/issues/28302
+[#28303]: https://github.com/JuliaLang/julia/issues/28303

src/Compat.jl

@@ -2011,6 +2011,25 @@ if VERSION < v"0.7.0-beta2.169"
     export floatmin, floatmax
 end
 
+# https://github.com/JuliaLang/julia/pull/28303
+if VERSION < v"0.7.0-beta2.143"
+    export dropdims
+    # https://github.com/JuliaLang/julia/pull/26660
+    if VERSION >= v"0.7.0-DEV.4738"
+        dropdims(
+            X;
+            dims = throw(
+                UndefKeywordError("dropdims: keyword argument dims not assigned"))
+        ) = squeeze(X, dims = dims)
+    else
+        dropdims(
+            X;
+            dims = throw(
+                UndefKeywordError("dropdims: keyword argument dims not assigned"))
+        ) = squeeze(X, dims)
+    end
+end
+
 include("deprecated.jl")
 
 end # module Compat

test/runtests.jl

@@ -1935,4 +1935,12 @@ end
 @test floatmax(Float32) == @eval $(Core.Intrinsics.bitcast(Float32, 0x7f7fffff))
 @test floatmin(zero(Float64)) == floatmin(Float64)
 
+# 0.7.0-beta2.143
+if VERSION < v"0.7.0-beta2.143"
+    let a = reshape(Vector(1:4),(2,2,1,1)), b = reshape(Vector(1:4), (2,2,1))
+        @test dropdims(a; dims=3) == b
+        @test_throws UndefKeywordError dropdims(a)
+    end
+end
+
 nothing