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Implement more operators on Nullable with lifting semantics #19034

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Implement more operators on Nullable with lifting semantics #19034

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2 changes: 1 addition & 1 deletion base/math.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ export sin, cos, tan, sinh, cosh, tanh, asin, acos, atan,
erfinv, erfcinv, @evalpoly

import Base: log, exp, sin, cos, tan, sinh, cosh, tanh, asin,
acos, atan, asinh, acosh, atanh, sqrt, log2, log10,
acos, atan, asinh, acosh, atanh, sqrt, cbrt, log2, log10,
max, min, minmax, ^, exp2, muladd,
exp10, expm1, log1p,
sign_mask, exponent_mask, exponent_one, exponent_half,
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78 changes: 78 additions & 0 deletions base/nullable.jl
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Expand Up @@ -215,3 +215,81 @@ function hash(x::Nullable, h::UInt)
return hash(x.value, h + nullablehash_seed)
end
end

# Unary operators

# Note this list does not include sqrt since it can raise a DomainError
for op in (+, -, abs, abs2)
null_safe_op{T<:NullSafeTypes}(::typeof(op), ::Type{T}) = true
null_safe_op{S<:NullSafeTypes,
T<:NullSafeTypes}(::typeof(op), ::Type{Complex{S}}, ::Type{Complex{T}}) = true
null_safe_op{S<:NullSafeTypes,
T<:NullSafeTypes}(::typeof(op), ::Type{Rational{S}}, ::Type{Rational{T}}) = true
end

null_safe_op{T<:NullSafeInts}(::typeof(~), ::Type{T}) = true
null_safe_op(::typeof(!), ::Type{Bool}) = true

for op in (:+, :-, :!, :~, :abs, :abs2, :sqrt, :cbrt)
@eval begin
@inline function $op{S}(x::Nullable{S})
R = promote_op($op, S)
if null_safe_op($op, S)
Nullable{R}($op(x.value), !isnull(x))
else
isnull(x) ? Nullable{R}() :
Nullable{R}($op(x.value))
end
end
$op(x::Nullable{Union{}}) = Nullable()
end
end

# These can only be defined after cbrt above
null_safe_op{T<:NullSafeTypes}(::typeof(cbrt), ::Type{T}) = true
null_safe_op{S<:NullSafeTypes,
T<:NullSafeTypes}(::typeof(cbrt), ::Type{Rational{S}}, ::Type{Rational{T}}) = true

# Binary operators

# Note this list does not include ^, ÷ and %
# Operations between signed and unsigned types are not safe: promotion to unsigned
# gives an InexactError for negative numbers
for op in (+, -, *, /, &, |, <<, >>, >>>,
scalarmin, scalarmax)
# to fix ambiguities
null_safe_op{S<:NullSafeFloats,
T<:NullSafeFloats}(::typeof(op), ::Type{S}, ::Type{T}) = true
null_safe_op{S<:NullSafeSignedInts,
T<:NullSafeSignedInts}(::typeof(op), ::Type{S}, ::Type{T}) = true
null_safe_op{S<:NullSafeUnsignedInts,
T<:NullSafeUnsignedInts}(::typeof(op), ::Type{S}, ::Type{T}) = true
end
for op in (+, -, *, /)
null_safe_op{S<:NullSafeSignedInts,
T<:NullSafeSignedInts}(::typeof(op), ::Type{Complex{S}}, ::Type{Complex{T}}) = true
null_safe_op{S<:NullSafeSignedInts,
T<:NullSafeSignedInts}(::typeof(op), ::Type{Rational{S}}, ::Type{Rational{T}}) = true
null_safe_op{S<:NullSafeUnsignedInts,
T<:NullSafeUnsignedInts}(::typeof(op), ::Type{Complex{S}}, ::Type{Complex{T}}) = true
null_safe_op{S<:NullSafeUnsignedInts,
T<:NullSafeUnsignedInts}(::typeof(op), ::Type{Rational{S}}, ::Type{Rational{T}}) = true
end

for op in (:+, :-, :*, :/, :%, :÷, :&, :|, :^, :<<, :>>, :(>>>),
:scalarmin, :scalarmax)
@eval begin
@inline function $op{S,T}(x::Nullable{S}, y::Nullable{T})
R = promote_op($op, S, T)
if null_safe_op($op, S, T)
Nullable{R}($op(x.value, y.value), !(isnull(x) | isnull(y)))
else
(isnull(x) | isnull(y)) ? Nullable{R}() :
Nullable{R}($op(x.value, y.value))
end
end
$op(x::Nullable{Union{}}, y::Nullable{Union{}}) = Nullable()
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Are the definitions with Union{} really necessary? I thought promote_op would handle that.

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The problem is that Union{} <: NullSafeTypes, so it would be considered as safe and we would try applying the operation even if the value field isn't defined. One alternative is to define null_safe_op for Union{} for each operation (to avoid ambiguities), which isn't cleaner. Not sure whether there's a better way of doing this.

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That could potentially be fixed by defining NullSafeTypes as Union{Type{Int8}, Type{Int16}, ...}.

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Ah, interesting. I will have a look at this solution.

$op{S}(x::Nullable{Union{}}, y::Nullable{S}) = Nullable{S}()
$op{S}(x::Nullable{S}, y::Nullable{Union{}}) = Nullable{S}()
end
end
188 changes: 188 additions & 0 deletions test/nullable.jl
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Expand Up @@ -282,6 +282,64 @@ for T in types
end

# Operators

SafeTestTypes = Union{Base.NullSafeTypes, BigInt, BigFloat,
Complex{Int}, Complex{Float64}, Rational{Int}}.types

# check for fast path (null-safe combinations of operators and types)
for S in Base.NullSafeTypes.types, T in Base.NullSafeTypes.types
# mixing signed and unsigned types is unsafe (slow path tested below)
if !((S <: Signed && T <: Signed) ||
(S <: Unsigned && T <: Unsigned) ||
(S <: AbstractFloat && T <: AbstractFloat) ||
(S == T))
continue
end

u0 = zero(S)
u1 = one(S)
u2 = rand(S)

v0 = zero(T)
v1 = one(T)
v2 = rand(T)

# safe unary operators
for op in (+, -, ~, abs, abs2, cbrt)
S <: AbstractFloat && op == (~) && continue
!(T <: Real) && op == cbrt && continue

@test op(Nullable(u0)) === Nullable(op(u0))
@test op(Nullable(u1)) === Nullable(op(u1))
@test op(Nullable(u2)) === Nullable(op(u2))
@test op(Nullable(u0, false)) === Nullable(op(u0), false)
end

for u in (u0, u1, u2), v in (v0, v1, v2)
# safe binary operators: === checks that the fast-path was taken (no branch)
for op in (+, -, *, /, &, |, >>, <<, >>>,
Base.scalarmin, Base.scalarmax)
(T <: AbstractFloat || S <: AbstractFloat) && op in (&, |, >>, <<, >>>) && continue

@test op(Nullable(u), Nullable(v)) === Nullable(op(u, v))
@test op(Nullable(u, false), Nullable(v, false)) === Nullable(op(u, v), false)
@test op(Nullable(u), Nullable(v, false)) === Nullable(op(u, v), false)
@test op(Nullable(u, false), Nullable(v)) === Nullable(op(u, v), false)
end
end
end

@test !Nullable(true) === Nullable(false)
@test !Nullable(false) === Nullable(true)
@test !(Nullable(true, false)) === Nullable(false, false)
@test !(Nullable(false, false)) === Nullable(true, false)

# test all types and operators (including null-unsafe ones)

ensure_neg(x::Unsigned) = -convert(Signed, x)
ensure_neg{T<:Complex}(x::T) = T(-abs(real(x)), -abs(imag(x)))
ensure_neg(x::Any) = -abs(x)

TestTypes = Union{Base.NullSafeTypes, BigInt, BigFloat,
Complex{Int}, Complex{Float64}, Complex{BigFloat},
Rational{Int}, Rational{BigInt}}.types
Expand All @@ -306,7 +364,137 @@ for S in TestTypes, T in TestTypes
v2 = v1
end

# safe unary operators
for op in (+, -, ~, abs, abs2, cbrt)
!(T <: Integer) && op == (~) && continue
!(T <: Real) && op == cbrt && continue

R = Base.promote_op(op, T)
x = op(Nullable(v0))
@test isa(x, Nullable{R}) && isequal(x, Nullable(op(v0)))
x = op(Nullable(v1))
@test isa(x, Nullable{R}) && isequal(x, Nullable(op(v1)))
x = op(Nullable(v2))
@test isa(x, Nullable{R}) && isequal(x, Nullable(op(v2)))
x = op(Nullable(v0, false))
@test isa(x, Nullable{R}) && isnull(x)
x = op(Nullable(v1, false))
@test isa(x, Nullable{R}) && isnull(x)
x = op(Nullable(v2, false))
@test isa(x, Nullable{R}) && isnull(x)
x = op(Nullable{R}())
@test isa(x, Nullable{R}) && isnull(x)

x = op(Nullable())
@test isa(x, Nullable{Union{}}) && isnull(x)
end

# unsafe unary operators
# sqrt
T <: Real && @test_throws DomainError sqrt(Nullable(ensure_neg(v1)))
R = Base.promote_op(sqrt, T)
x = sqrt(Nullable(v0))
@test isa(x, Nullable{R}) && isequal(x, Nullable(sqrt(v0)))
x = sqrt(Nullable(v1))
@test isa(x, Nullable{R}) && isequal(x, Nullable(sqrt(v1)))
x = sqrt(Nullable(v0, false))
@test isa(x, Nullable{R}) && isnull(x)
x = sqrt(Nullable(ensure_neg(v1), false))
@test isa(x, Nullable{R}) && isnull(x)
x = sqrt(Nullable(ensure_neg(v2), false))
@test isa(x, Nullable{R}) && isnull(x)
x = sqrt(Nullable{R}())
@test isa(x, Nullable{R}) && isnull(x)

x = sqrt(Nullable())
@test isa(x, Nullable{Union{}}) && isnull(x)

for u in (u0, u1, u2), v in (v0, v1, v2)
# safe binary operators
for op in (+, -, *, /, &, |, >>, <<, >>>,
Base.scalarmin, Base.scalarmax)
(T <: AbstractFloat || S <: AbstractFloat) && op in (&, |, >>, <<, >>>) && continue
(T <: Bool || S <: Bool) && op in (>>, <<, >>>) && continue
(T <: BigInt || S <: BigInt) && op in (&, |, >>, <<, >>>) && continue
(T <: Complex || S <: Complex) && op in (&, |, >>, <<, >>>, Base.scalarmin, Base.scalarmax) && continue
(T <: Rational || S <: Rational) && op in (-, /, &, |, >>, <<, >>>, Base.scalarmin, Base.scalarmax) && continue

if S <: Unsigned || T <: Unsigned
@test isequal(op(Nullable(abs(u)), Nullable(abs(v))), Nullable(op(abs(u), abs(v))))
else
@test isequal(op(Nullable(u), Nullable(v)), Nullable(op(u, v)))
end
R = Base.promote_op(op, S, T)
x = op(Nullable(u, false), Nullable(v, false))
@test isa(x, Nullable{R}) && isnull(x)
x = op(Nullable(u), Nullable(v, false))
@test isa(x, Nullable{R}) && isnull(x)
x = op(Nullable(u, false), Nullable(v))
@test isa(x, Nullable{R}) && isnull(x)

x = op(Nullable(u, false), Nullable())
@test isa(x, Nullable{S}) && isnull(x)
x = op(Nullable(), Nullable(u, false))
@test isa(x, Nullable{S}) && isnull(x)
x = op(Nullable(), Nullable())
@test isa(x, Nullable{Union{}}) && isnull(x)
end

# unsafe binary operators
# ^
if S <: Integer && T <: Integer && u != 0 && u != 1 && v != 0
@test_throws DomainError Nullable(u)^Nullable(ensure_neg(v))
end
@test isequal(Nullable(u)^Nullable(one(T)+one(T)), Nullable(u^(one(T)+one(T))))
R = Base.promote_op(^, S, T)
if S <: Real && T <: Real
x = Nullable(u, false)^Nullable(-abs(v), false)
@test isnull(x) && eltype(x) === R
x = Nullable(u, true)^Nullable(-abs(v), false)
@test isnull(x) && eltype(x) === R
x = Nullable(u, false)^Nullable(-abs(v), true)
@test isnull(x) && eltype(x) === R
else
x = Nullable(u, false)^Nullable(v, false)
@test isnull(x) && eltype(x) === R
x = Nullable(u, true)^Nullable(v, false)
@test isnull(x) && eltype(x) === R
x = Nullable(u, false)^Nullable(v, true)
@test isnull(x) && eltype(x) === R
end

x = Nullable(u, false)^Nullable()
@test isa(x, Nullable{S}) && isnull(x)
x = Nullable()^Nullable(u, false)
@test isa(x, Nullable{S}) && isnull(x)
x = Nullable()^Nullable()
@test isa(x, Nullable{Union{}}) && isnull(x)

if S <: Real && T <: Real
# ÷ and %
for op in (÷, %)
if S <: Union{Integer, Rational} && T <: Union{Integer, Rational} && v == 0
@test_throws DivideError op(Nullable(u), Nullable(v))
else
@test isequal(op(Nullable(u), Nullable(v)), Nullable(op(u, v)))
end
R = Base.promote_op(op, S, T)
x = op(Nullable(u, false), Nullable(v, false))
@test isnull(x) && eltype(x) === R
x = op(Nullable(u, true), Nullable(v, false))
@test isnull(x) && eltype(x) === R
x = op(Nullable(u, false), Nullable(v, true))
@test isnull(x) && eltype(x) === R

x = op(Nullable(u, false), Nullable())
@test isa(x, Nullable{S}) && isnull(x)
x = op(Nullable(), Nullable(u, false))
@test isa(x, Nullable{S}) && isnull(x)
x = op(Nullable(), Nullable())
@test isa(x, Nullable{Union{}}) && isnull(x)
end
end

# function isequal(x::Nullable, y::Nullable)
@test isequal(Nullable(u), Nullable(v)) === isequal(u, v)
@test isequal(Nullable(u), Nullable(u)) === true
Expand Down