Handle elementwise array math + change imports to usings (#13)

Author: BioTurboNick

src/OverflowContexts.jl

@@ -2,6 +2,7 @@ module OverflowContexts
 
 include("macros.jl")
 include("base_ext.jl")
+include("abstractarraymath_ext.jl")
 
 export @default_checked, @default_unchecked, @checked, @unchecked,
     unchecked_neg, unchecked_add, unchecked_sub, unchecked_mul, unchecked_negsub, unchecked_pow, unchecked_abs,

src/abstractarraymath_ext.jl

@@ -0,0 +1,34 @@
+import Base.Checked: checked_neg, checked_add, checked_sub, checked_mul
+if VERSION ≥ v"1.11-alpha"
+    import Base.Checked: checked_pow
+end
+if VERSION ≥ v"1.2"
+    using Base: broadcast_preserving_zero_d
+end
+
+checked_neg(A::AbstractArray) = broadcast_preserving_zero_d(checked_neg, A)
+for f in (:checked_add, :checked_sub)
+    @eval function ($f)(A::AbstractArray, B::AbstractArray)
+        promote_shape(A, B) # check size compatibility
+        broadcast_preserving_zero_d($f, A, B)
+    end
+end
+checked_mul(A::Number, B::AbstractArray) = broadcast_preserving_zero_d(checked_mul, B, A)
+checked_mul(A::AbstractArray, B::Number) = broadcast_preserving_zero_d(checked_mul, A, B)
+checked_mul(A::AbstractArray, B::AbstractArray) = error("Checked matrix multiplication is not available")
+
+checked_pow(A::AbstractArray, B::Number) = error("Checked matrix multiplication is not available")
+
+# Compatibility with Julia 1.0 and 1.1
+if VERSION < v"1.2"
+    if VERSION < v"1.1"
+        @inline materialize(bc::Base.Broadcast.Broadcasted) = copy(Base.Broadcast.instantiate(bc))
+    else
+        using Base.Broadcast: materialize
+    end
+    @inline function broadcast_preserving_zero_d(f, As...)
+        bc = Base.Broadcast.broadcasted(f, As...)
+        r = materialize(bc)
+        return length(axes(bc)) == 0 ? fill!(similar(bc, typeof(r)), r) : r
+    end
+end

src/base_ext.jl

@@ -1,11 +1,11 @@
-import Base: promote, afoldl, @_inline_meta
+using Base: promote, afoldl, @_inline_meta
 import Base.Checked: checked_neg, checked_add, checked_sub, checked_mul, checked_abs  
 
 if VERSION ≥ v"1.11-alpha"
     import Base.Checked: checked_pow
 else
-    import Base: BitInteger, throw_domerr_powbysq, to_power_type
-    import Base.Checked: mul_with_overflow, throw_overflowerr_binaryop
+    using Base: BitInteger, throw_domerr_powbysq, to_power_type
+    using Base.Checked: mul_with_overflow, throw_overflowerr_binaryop
 end
 
 # The Base methods have unchecked semantics, so just pass through

src/macros.jl

@@ -1,4 +1,4 @@
-import Base.Meta: isexpr
+using Base.Meta: isexpr
 
 const op_method_symbols = (:+, :-, :*, :^, :abs)
 

test/runtests.jl

@@ -301,3 +301,26 @@ using SaferIntegers
             @test_throws OverflowError typemax(SafeInt) + 1
         end))
 end
+
+@testset "Elementwise array methods are replaced, and others throw" begin
+    aa = fill(typemax(Int), 2)
+    bb = fill(2, 2)
+    cc = fill(typemin(Int), 2)
+    dd = fill(typemax(Int), 2, 2)
+    @unchecked(+cc) == cc
+    @unchecked(-cc) == cc
+    @checked(+cc) == cc
+    @test_throws OverflowError @checked(-cc)
+    @unchecked(aa + bb) == fill(typemin(Int) + 1, 2)
+    @test_throws OverflowError @checked aa + bb
+    @unchecked(cc - bb) == fill(typemax(Int) - 1, 2)
+    @test_throws OverflowError @checked cc - bb
+    @unchecked(2aa) == fill(-2, 2)
+    @test_throws OverflowError @checked 2aa
+    @unchecked(aa * 2) == fill(-2, 2)
+    @test_throws OverflowError @checked aa * 2
+    @unchecked(aa * bb') == fill(-2, 2, 2)
+    @test_throws ErrorException @checked aa * bb'
+    @unchecked(dd ^ 2) == fill(2, 2, 2)
+    @test_throws ErrorException @checked dd ^ 2
+end