Merge pull request #41 from JuliaData/jq/promote

Fix #23 by defining a few more helper promote_rule definitions
JuliaData · Oct 4, 2017 · b0a5c55 · b0a5c55
2 parents 3d11e09 + 14e9325
commit b0a5c55
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diff --git a/src/Nulls.jl b/src/Nulls.jl
@@ -24,6 +24,11 @@ nulls(::Type{T}, dims...) where {T >: Null} = fill!(Array{T}(dims), null)
 nulls(::Type{T}, dims...) where {T} = fill!(Array{Union{T, Null}}(dims), null)
 
 Base.promote_rule(::Type{T}, ::Type{Null}) where {T} = Union{T, Null}
+Base.promote_rule(::Type{T}, ::Type{Union{S,Null}}) where {T,S} = Union{promote_type(T, S), Null}
+Base.promote_rule(::Type{T}, ::Type{Any}) where {T} = Any
+Base.promote_rule(::Type{Any}, ::Type{Null}) = Any
+Base.promote_rule(::Type{Null}, ::Type{Any}) = Any
+Base.promote_rule(::Type{Null}, ::Type{Null}) = Null
 Base.convert(::Type{Union{T, Null}}, x) where {T} = convert(T, x)
 
 # Comparison operators

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -2,6 +2,24 @@ using Base.Test, Nulls
 
 @testset "Nulls" begin
 
+    # test promote rules
+    @test promote_type(Null, Null) == Null
+    @test promote_type(Null, Int) == Union{Null, Int}
+    @test promote_type(Int, Null) == Union{Null, Int}
+    @test promote_type(Int, Any) == Any
+    @test promote_type(Any, Any) == Any
+    @test promote_type(Null, Any) == Any
+    @test promote_type(Any, Null) == Any
+    @test promote_type(Union{Int, Null}, Null) == Union{Int, Null}
+    @test promote_type(Null, Union{Int, Null}) == Union{Int, Null}
+    @test promote_type(Union{Int, Null}, Int) == Union{Int, Null}
+    @test promote_type(Int, Union{Int, Null}) == Union{Int, Null}
+    @test promote_type(Any, Union{Int, Null}) == Any
+    @test promote_type(Union{Int, Null}, Union{Int, Null}) == Union{Int, Null}
+    @test promote_type(Union{Float64, Null}, Union{String, Null}) == Any
+    @test promote_type(Union{Float64, Null}, Union{Int, Null}) == Union{Float64, Null}
+    @test promote_type(Union{Void, Null, Int}, Float64) == Any
+
     bit_operators = [&, |, ⊻]
 
     arithmetic_operators = [+, -, *, /, ^, Base.div, Base.mod, Base.fld, Base.rem]