add rem(::Integer, ::Type{T<:Integer}}) functions from JuliaLang/juli…

…a#8646

README.md

@@ -90,7 +90,7 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 ## Renamed functions
 
-* `itrunc`, `iround`, `iceil`, `ifloor` are now accessed via `trunc(T, x)`, etc. [#9133](https://github.com/JuliaLang/julia/pull/9133)
+* `itrunc`, `iround`, `iceil`, `ifloor` are now accessed via `trunc(T, x)`, etc. ([#9133](https://github.com/JuliaLang/julia/pull/9133)).  Truncated conversions between integer types are now `n % T` ([#8646](https://github.com/JuliaLang/julia/issues/8646)).
 
 * `Base.Random.randmtzig_exprnd` is now `randexp` [#9144](https://github.com/JuliaLang/julia/pull/9144)
 

src/Compat.jl

@@ -96,6 +96,14 @@ if VERSION < v"0.4.0-dev+1827"
     end
 end
 
+if VERSION < v"0.4.0-dev+838"
+    Base.rem{T<:Integer}(n::Integer, ::Type{T}) = convert(T, n)
+elseif VERSION < v"0.4.0-dev+1037"
+    Base.rem{T<:Integer}(n::Integer, ::Type{T}) = itrunc(T, n)
+elseif VERSION < v"0.4.0-dev+1039"
+    Base.rem{T<:Integer}(n::Integer, ::Type{T}) = mod(n, T)
+end
+
 if VERSION < v"0.4.0-dev+1884"
     randexp(rng::MersenneTwister) = Base.Random.randmtzig_exprnd(rng)
     randexp() = Base.Random.randmtzig_exprnd()

test/runtests.jl

@@ -97,6 +97,24 @@ end
 @test trunc(Int, [1.1 1.1]) == [1 1]
 @test trunc(Int, fill(1.1, 2, 3, 4)) == fill(1, 2, 3, 4)
 
+# n % Type
+for T in Any[Int16, Int32, UInt32, Int64, UInt64]
+    if !(T <: Unsigned)
+        @test convert(T, -200) %  Int8 === @compat Int8(56)
+        @test convert(T, -200) % UInt8 === 0x38
+        @test convert(T, -300) %  Int8 === @compat Int8(-44)
+        @test convert(T, -300) % UInt8 === 0xd4
+        @test convert(T, -128) %  Int8 === @compat Int8(-128)
+        @test convert(T, -128) % UInt8 === 0x80
+    end
+    @test convert(T,  127) %  Int8 === @compat Int8(127)
+    @test convert(T,  127) % UInt8 === 0x7f
+    @test convert(T,  128) %  Int8 === @compat Int8(-128)
+    @test convert(T,  128) % UInt8 === 0x80
+    @test convert(T,  200) %  Int8 === @compat Int8(-56)
+    @test convert(T,  300) % UInt8 === 0x2c
+end
+
 @test IPv4("1.2.3.4") == ip"1.2.3.4"
 @test IPv6("2001:1:2:3::1") == ip"2001:1:2:3::1"
 @test isless(ip"1.2.3.4", ip"1.2.3.5")