add allequal

Project.toml

@@ -1,6 +1,6 @@
 name = "Compat"
 uuid = "34da2185-b29b-5c13-b0c7-acf172513d20"
-version = "3.41.0"
+version = "3.42.0"
 
 [deps]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"

README.md

@@ -54,6 +54,8 @@ changes in `julia`.
 
 ## Supported features
 
+* `allequal`, the opposite of `allunique` ([#43354]). (since Compat 3.42.0)
+
 * `eachsplit` for iteratively performing split(str). ([#39245]). (since Compat 3.41.0)
 
 * `ismutabletype(t::Type)` check whether a type is mutable (the field `mutable` of `DataType` was removed. [#39037]) (since Compat 3.40)
@@ -290,3 +292,4 @@ Note that you should specify the correct minimum version for `Compat` in the
 [#42125]: https://github.com/JuliaLang/julia/pull/42125
 [#41312]: https://github.com/JuliaLang/julia/pull/41312
 [#41328]: https://github.com/JuliaLang/julia/pull/41328
+[#43354]: https://github.com/JuliaLang/julia/pull/43354

src/Compat.jl

@@ -1314,6 +1314,16 @@ if VERSION < v"1.8.0-DEV.487"
     eachsplit(str::AbstractString; limit::Integer=0, keepempty=false) =
         eachsplit(str, isspace; limit=limit, keepempty=keepempty)
 end
+
+# https://github.com/JuliaLang/julia/pull/43354
+if VERSION < v"1.8.0-DEV.1494" # 98e60ffb11ee431e462b092b48a31a1204bd263d
+    export allequal
+    allequal(itr) = isempty(itr) ? true : all(isequal(first(itr)), itr)
+    allequal(c::Union{AbstractSet,AbstractDict}) = length(c) <= 1
+    allequal(r::AbstractRange) = iszero(step(r)) || length(r) <= 1
+end
+
+
 include("iterators.jl")
 include("deprecated.jl")
 

test/runtests.jl

@@ -1370,4 +1370,34 @@ so, these are the Base.split tests, but replacing split with eachsplit |> collec
         eachsplit("α β γ", isspace) |> collect == rsplit("α β γ", isspace) == ["α","β","γ"]
     @test eachsplit("ö.", ".") |> collect == rsplit("ö.", ".") == ["ö",""]
     @test eachsplit("α β γ", "β") |> collect == rsplit("α β γ", "β") == ["α "," γ"]
-end
+end
+
+# https://github.com/JuliaLang/julia/pull/43354
+@testset "allequal" begin
+    @test allequal(Set())
+    @test allequal(Set(1))
+    @test !allequal(Set([1, 2]))
+    @test allequal(Dict())
+    @test allequal(Dict(:a => 1))
+    @test !allequal(Dict(:a => 1, :b => 2))
+    @test allequal([])
+    @test allequal([1])
+    @test allequal([1, 1])
+    @test !allequal([1, 1, 2])
+    @test allequal([:a, :a])
+    @test !allequal([:a, :b])
+    @test !allequal(1:2)
+    @test allequal(1:1)
+    @test !allequal(4.0:0.3:7.0)
+    @test allequal(4:-1:5)       # empty range
+    @test !allequal(7:-1:1)       # negative step
+    @test !allequal(Date(2018, 8, 7):Day(1):Date(2018, 8, 11))  # JuliaCon 2018
+    @test !allequal(DateTime(2018, 8, 7):Hour(1):DateTime(2018, 8, 11))
+    @test allequal(StepRangeLen(1.0, 0.0, 2))
+    @test !allequal(StepRangeLen(1.0, 1.0, 2))
+    @test allequal(LinRange(1, 1, 0))
+    @test allequal(LinRange(1, 1, 1))
+    @test allequal(LinRange(1, 1, 2))
+    @test !allequal(LinRange(1, 2, 2))
+end
+