Allow clamp(n, 1:10) (JuliaLang#37548)

* clamp method for unitrange

* add tests & narrower type

* move to Base.Math

* triple equals

Co-authored-by: Michael Abbott <me@escbook>

base/math.jl

@@ -97,6 +97,15 @@ function clamp!(x::AbstractArray, lo, hi)
  x
 end
 
+"""
+ clamp(x::Integer, r::AbstractUnitRange)
+
+Clamp `x` to lie within range `r`.
+
+!!! compat "Julia 1.6"
+ This method requires at least Julia 1.6.
+"""
+clamp(x::Integer, r::AbstractUnitRange{<:Integer}) = clamp(x, first(r), last(r))
 
 """
  evalpoly(x, p)

test/ranges.jl

@@ -1633,6 +1633,20 @@ end
  @test_throws DivideError mod(3, 1:0)
 end
 
+@testset "clamp with unitrange" begin
+ for n in -10:10
+ @test clamp(n, 0:4) == clamp(n, 0, 4)
+ @test clamp(n, Base.OneTo(5)) == clamp(n, 1, 5)
+ end
+ @test clamp(Int32(3), 1:5) === Int(3)
+ @test clamp(big(typemax(Int))+99, 0:4) == 4
+ @test_throws MethodError clamp(3.141, 1:5)
+ @test_throws MethodError clamp(3, UnitRange(1.0,5.0))
+ @test_throws MethodError clamp(3, 1:2:7)
+ @test clamp(3, 1:0) == clamp(3, 1, 0) == 0
+ @test clamp(-3, 1:0) == clamp(-3, 1, 0) == 1
+end
+
 @testset "issue #33882" begin
  r = StepRangeLen('a',2,4)
  @test step(r) === 2