Merge d173345 into 4d8facd

JuliaData · Feb 14, 2021 · 8523716 · 8523716
2 parents 4d8facd + d173345
commit 8523716
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diff --git a/src/DataAPI.jl b/src/DataAPI.jl
@@ -169,4 +169,18 @@ struct Cols{T<:Tuple}
     Cols(args...) = new{typeof(args)}(args)
 end
 
+"""
+    unwrap(x)
+
+For a given scalar argument `x`, potentially "unwrap" it to return the base wrapped value.
+Useful as a generic API for wrapper types when the original value is needed.
+
+The default definition just returns `x` itself, i.e. no unwrapping is performned.
+
+This generic function is owned by DataAPI.jl itself, which is the sole provider of the
+default definition.
+"""
+function unwrap end
+unwrap(x) = x
+
 end # module
diff --git a/test/runtests.jl b/test/runtests.jl
@@ -85,4 +85,9 @@ end
 
 end
 
+@testset "unwrap" begin
+    @test DataAPI.unwrap(1) === 1
+    @test DataAPI.unwrap(missing) === missing
+end
+
 end # @testset "DataAPI"