Add support for rand(1..2) (#104)

* add dependency on Random

* add dependency on Random

* add draft method for rand(::Interval)

* update Random.rand and Random.gentype

* add clamp and replace Interval{L,R} with ClosedInterval in Random.rand

* add tests for rand

Author: hyrodium

Project.toml

@@ -4,6 +4,7 @@ version = "0.7.0"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]

src/IntervalSets.jl

@@ -6,6 +6,7 @@ import Base: eltype, convert, show, in, length, isempty, isequal, issubset, ==,
 
 using Statistics
 import Statistics: mean
+using Random
 
 using Dates
 

src/interval.jl

@@ -223,6 +223,16 @@ function _union(A::TypedEndpointsInterval{L1,R1}, B::TypedEndpointsInterval{L2,R
     Interval{L,R}(left, right)
 end
 
+# random sampling from interval
+Random.gentype(::Type{Interval{L,R,T}}) where {L,R,T} = float(T)
+function Random.rand(rng::AbstractRNG, i::Random.SamplerTrivial{ClosedInterval{T}}) where {T<:Real}
+    _i = i[]
+    isempty(_i) && throw(ArgumentError("The interval should be non-empty."))
+    a,b = endpoints(_i)
+    t = rand(rng, float(T))
+    return clamp(t*a+(1-t)*b, _i)
+end
+
 ClosedInterval{T}(i::AbstractUnitRange{I}) where {T,I<:Integer} = ClosedInterval{T}(minimum(i), maximum(i))
 ClosedInterval(i::AbstractUnitRange{I}) where {I<:Integer} = ClosedInterval{I}(minimum(i), maximum(i))
 

test/runtests.jl

@@ -707,6 +707,34 @@ struct IncompleteInterval <: AbstractInterval{Int} end
         @test clamp.([pi, 1.0, big(10.)], Ref(2..9.)) == [big(pi), 2, 9]
     end
 
+    @testset "rand" begin
+        @test rand(1..2) isa Float64
+        @test rand(1..2.) isa Float64
+        @test rand(1..big(2)) isa BigFloat
+        @test rand(1..(3//2)) isa Float64
+        @test rand(Int32(1)..Int32(2)) isa Float64
+        @test rand(Float32(1)..Float32(2)) isa Float32
+        @test_throws ArgumentError rand(2..1)
+
+        i1 = 1..2
+        i2 = 3e100..3e100
+        i3 = 1..typemax(Float64)
+        i4 = typemin(Float64)..typemax(Float64)
+        i5 = typemin(Float64)..1
+        for _ in 1:100
+            rand(i1) in i1
+            rand(i2) in i2
+            rand(i3) in i3
+            rand(i4) in i4
+            rand(i5) in i5
+            rand(i1,10) ⊆ i1
+            rand(i2,10) ⊆ i2
+            rand(i3,10) ⊆ i3
+            rand(i4,10) ⊆ i4
+            rand(i5,10) ⊆ i5
+        end
+    end
+
     @testset "IteratorSize" begin
         @test Base.IteratorSize(ClosedInterval) == Base.SizeUnknown()
     end