allequal(f, itr) and allunique(f, itr) (#818)

Author: mcabbott

Project.toml

@@ -1,6 +1,6 @@
 name = "Compat"
 uuid = "34da2185-b29b-5c13-b0c7-acf172513d20"
-version = "4.12.0"
+version = "4.13.0"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"

README.md

@@ -70,6 +70,8 @@ changes in `julia`.
 
 ## Supported features
 
+* `allequal(f, itr)` and `allunique(f, itr)` methods. ([#47679]) (since Compat 4.13.0)
+
 * `Iterators.cycle(itr, n)` is the lazy version of `repeat(vector, n)`. ([#47354]) (since Compat 4.13.0)
 
 * `@compat public foo, bar` marks `foo` and `bar` as public in Julia 1.11+ and is a no-op in Julia 1.10 and earlier. ([#50105]) (since Compat 3.47.0, 4.10.0)
@@ -181,3 +183,4 @@ Note that you should specify the correct minimum version for `Compat` in the
 [#47354]: https://github.com/JuliaLang/julia/issues/47354
 [#48038]: https://github.com/JuliaLang/julia/issues/48038
 [#50105]: https://github.com/JuliaLang/julia/issues/50105
+[#47679]: https://github.com/JuliaLang/julia/pull/47679

src/Compat.jl

@@ -330,6 +330,8 @@ if VERSION < v"1.8.0-DEV.1494" # 98e60ffb11ee431e462b092b48a31a1204bd263d
     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
+else
+    import Base: allequal  # extended below
 end
 
 # https://github.com/JuliaLang/julia/commit/bdf9ead91e5a8dfd91643a17c1626032faada329
@@ -770,6 +772,27 @@ if VERSION < v"1.7.0-DEV.1187"
     export redirect_stdio
 end
 
+# https://github.com/JuliaLang/julia/pull/47679
+if VERSION < v"1.11.0-DEV.1562"
+    Base.allunique(f, xs) = allunique(Base.Generator(f, xs))
+    function Base.allunique(f::F, t::Tuple) where {F}
+        length(t) < 2 && return true
+        length(t) < 32 || return Base._hashed_allunique(Base.Generator(f, t))
+        return allunique(map(f, t))
+    end
+    
+    # allequal is either imported or defined above
+    allequal(f, xs) = allequal(Base.Generator(f, xs))
+    function allequal(f, xs::Tuple)
+        length(xs) <= 1 && return true
+        f1 = f(xs[1])
+        for x in Base.tail(xs)
+            isequal(f1, f(x)) || return false
+        end
+        return true
+    end
+end
+
 # https://github.com/JuliaLang/julia/pull/45052
 if VERSION < v"1.9.0-DEV.461"
     Base.VersionNumber(v::VersionNumber) = v

test/runtests.jl

@@ -729,6 +729,34 @@ end
     @test_throws LoadError @eval @compat publac @bar, foo
 end
 
+# https://github.com/JuliaLang/julia/pull/47679
+@testset "allunique(f, xs)" begin
+    @test allunique(sin, 1:3)
+    @test !allunique(sin, [1,2,3,1])
+    @test allunique(sin, (1, 2, pi, im))  # eltype Any
+    @test allunique(abs2, 1:100)
+    @test !allunique(abs, -10:10)
+    @test allunique(abs2, Vector{Any}(1:100))
+    # These cases don't call the function at all:
+    @test allunique(error, [])
+    @test_skip allunique(error, [1]) # depends on updated code in Base to work
+end
+@testset "allequal(f, xs)" begin
+    @test allequal(abs2, [3, -3])
+    @test allequal(x -> 1, rand(3))
+    @test !allequal(x -> rand(), [1,1,1])
+    # tuples
+    @test allequal(abs2, (3, -3))
+    @test allequal(x -> 1, Tuple(rand(3)))
+    @test !allequal(x -> rand(), (1,1,1))
+    # These cases don't call the function at all:
+    @test allequal(error, [])
+    @test allequal(error, ())
+    @test allequal(error, (x for x in 1:3 if false))
+    @test_skip allequal(error, [1])  # fixed not by new code but by upgrades to old code
+    @test allequal(error, (1,))
+end
+
 # https://github.com/JuliaLang/julia/pull/45052
 @testset "VersionNumber no-op constructor" begin
     v = VersionNumber("1.2.3")