mod(n, range) (#661)

* JuliaLang/julia#32628

Author: mcabbott

README.md

@@ -114,6 +114,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 ## New functions, macros, and methods
 
+* `mod` now accepts a unit range as the second argument ([#32628]).
+
 * `eachrow`, `eachcol`, and `eachslice` to iterate over first, second, or given dimension
   of an array ([#29749]).
 

src/Compat.jl

@@ -1866,6 +1866,12 @@ if v"0.7.0" <= VERSION < v"1.1.0-DEV.594"
     Base.merge(a::NamedTuple) = a
 end
 
+# https://github.com/JuliaLang/julia/pull/32628
+if v"0.7.0" <= VERSION < v"1.3.0-alpha.8"
+    Base.mod(i::Integer, r::Base.OneTo) = mod1(i, last(r))
+    Base.mod(i::Integer, r::AbstractUnitRange{<:Integer}) = mod(i-first(r), length(r)) + first(r)
+end
+
 include("deprecated.jl")
 
 end # module Compat

test/runtests.jl

@@ -38,7 +38,7 @@ if VERSION >= v"0.7"
         @test collect(eachrow(M)) == collect(eachslice(M, dims = 1)) == [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
         @test collect(eachcol(M)) == collect(eachslice(M, dims = 2)) == [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
         @test_throws DimensionMismatch eachslice(M, dims = 4)
-        
+
         # Higher-dimensional case
         M = reshape([(1:16)...], 2, 2, 2, 2)
         @test_throws MethodError collect(eachrow(M))
@@ -1499,4 +1499,22 @@ end
     @test merge((a=1,), (b=2,), (c=3,)) == (a=1,b=2,c=3)
 end
 
+# https://github.com/JuliaLang/julia/pull/32628
+if VERSION >= v"0.7"
+    @testset "mod with ranges" begin
+        for n in -10:10
+            @test mod(n, 0:4) == mod(n, 5)
+            @test mod(n, 1:5) == mod1(n, 5)
+            @test mod(n, 2:6) == 2 + mod(n-2, 5)
+            @test mod(n, Base.OneTo(5)) == mod1(n, 5)
+        end
+        @test mod(Int32(3), 1:5) == 3
+        @test mod(big(typemax(Int))+99, 0:4) == mod(big(typemax(Int))+99, 5)
+        @test_throws MethodError mod(3.141, 1:5)
+        @test_throws MethodError mod(3, UnitRange(1.0,5.0))
+        @test_throws MethodError mod(3, 1:2:7)
+        @test_throws DivideError mod(3, 1:0)
+    end
+end
+
 nothing