Allow operations mixing Nullable and scalar

src/operators.jl

@@ -19,6 +19,40 @@ for f in (
 end
 
 # Implement the binary operators: +, -, *, /, %, &, |, ^, <<, and >>
+# Prevent ambiguities with Base
+@inline function Base.(:^){S1, S2<:Integer}(x::Nullable{S1}, y::S2)
+ if isbits(S1) & isbits(S2)
+ Nullable(^(x.value, y), x.isnull)
+ else
+ throw_error()
+ end
+end
+
+for f in (
+ :(Base.(:<<)),
+ :(Base.(:>>))
+)
+ @eval begin
+ @inline function $(f){S1}(x::Nullable{S1}, y::Int)
+ if isbits(S1)
+ Nullable($(f)(x.value, y), x.isnull)
+ else
+ throw_error()
+ end
+ end
+ end
+
+ @eval begin
+ @inline function $(f){S1, T<:Integer}(x::Nullable{S1}, y::T)
+ if isbits(S1) && isbits(T)
+ Nullable($(f)(x.value, y), x.isnull)
+ else
+ throw_error()
+ end
+ end
+ end
+end
+
 for f in (
  :(Base.(:+)),
  :(Base.(:-)),
@@ -40,24 +74,38 @@ for f in (
  end
  end
  end
-end
 
-# Implement the binary operators: == and !=
-for f in (
- :(Base.(:(==))),
- :(Base.(:!=)),
-)
  @eval begin
- function $(f){S1, S2}(x::Nullable{S1}, y::Nullable{S2})
+ @inline function $(f){S1, S2}(x::Nullable{S1}, y::S2)
  if isbits(S1) & isbits(S2)
- Nullable{Bool}($(f)(x.value, y.value), x.isnull | y.isnull)
+ Nullable($(f)(x.value, y), x.isnull)
  else
- error()
+ throw_error()
  end
  end
  end
 end
 
+# Implement the binary operators: == and !=
+# Prevent ambiguity with Base
+Base.(:(==))(x::Nullable, y::WeakRef) = x == y.value
+
+function Base.(:(==)){S1, S2}(x::Nullable{S1}, y::Nullable{S2})
+ if isbits(S1) & isbits(S2)
+ Nullable{Bool}(x.value == y.value, x.isnull | y.isnull)
+ else
+ error()
+ end
+end
+
+function Base.(:(==)){S1, S2}(x::Nullable{S1}, y::S2)
+ if isbits(S1) & isbits(S2)
+ Nullable{Bool}(x.value == y, x.isnull)
+ else
+ error()
+ end
+end
+
 # Implement the binary operators: <, >, <=, and >=
 for f in (
  :(Base.(:<)),
@@ -74,6 +122,16 @@ for f in (
  end
  end
  end
+
+ @eval begin
+ function $(f){S1, S2}(x::Nullable{S1}, y::S2)
+ if isbits(S1) & isbits(S2)
+ Nullable{Bool}($(f)(x.value, y), x.isnull)
+ else
+ error()
+ end
+ end
+ end
 end
 
 # Miscellaneous lifted operators
@@ -112,6 +170,14 @@ function Base.call{S1, S2}(::Base.MinFun, x::Nullable{S1}, y::Nullable{S2})
  end
 end
 
+function Base.call{S1, S2}(::Base.MinFun, x::Nullable{S1}, y::Nullable{S2})
+ if isbits(S1) & isbits(S2)
+ return Nullable(Base.scalarmin(x.value, y.value), x.isnull | y.isnull)
+ else
+ error()
+ end
+end
+
 function Base.call{S1, S2}(::Base.MaxFun, x::Nullable{S1}, y::Nullable{S2})
  if isbits(S1) & isbits(S2)
  return Nullable(Base.scalarmax(x.value, y.value), x.isnull | y.isnull)

test/operators.jl

@@ -46,6 +46,9 @@ module TestOperators
  x = op(Nullable(v), Nullable(w))
  @test_approx_eq x.value op(v, w)
  @test !x.isnull
+ y = op(Nullable(v), w)
+ @test_approx_eq y.value op(v, w)
+ @test !y.isnull
  @test_throws ErrorException op(Nullable(rand(1)), Nullable(rand(1)))
  end
 
@@ -58,6 +61,9 @@ module TestOperators
  x = op(Nullable(v), Nullable(w))
  @test_approx_eq x.value op(v, w)
  @test !x.isnull
+ y = op(Nullable(v), w)
+ @test_approx_eq y.value op(v, w)
+ @test !y.isnull
  @test_throws ErrorException op(Nullable(rand(Bool, 1)), Nullable(rand(Bool, 1)))
  end
 
@@ -70,6 +76,9 @@ module TestOperators
  x = op(Nullable(v), Nullable(w))
  @test_approx_eq x.value op(v, w)
  @test !x.isnull
+ y = op(Nullable(v), w)
+ @test_approx_eq y.value op(v, w)
+ @test !y.isnull
  @test_throws ErrorException op(Nullable(rand(Int, 1)), Nullable(rand(Int, 1)))
  end
 end