Add [] as an alternative to get

NEWS.md

@@ -1,3 +1,6 @@
+# DataValues.jl v0.2.0 Release Notes
+* Add [] as an alternative to get
+
 # DataValues.jl v0.1.0 Release Notes
 * Add configurable whitelist lifting
 

README.md

@@ -34,6 +34,8 @@ semantics for ``DataValue``s.
 ``DataValue`` arguments without the use of the dot broadcast syntax.
 - The package provides a configurable whitelist approach to lifting (see
 below).
+- One can access or unpack the value within a ``DataValue`` either via the
+``get(x)`` function, or use the ``x[]`` syntax.
 
 Any help with this package would be greatly appreciated!
 

src/DataValues.jl

@@ -85,6 +85,14 @@ end
 
 get(x::DataValue) = isnull(x) ? throw(DataValueException()) : x.value
 
+"""
+    getindex(x::DataValue)
+
+Attempt to access the value of `x`. Throw a `DataValueException` if the
+value is not present. Usually, this is written as `x[]`.
+"""
+Base.getindex(x::DataValue) = isnull(x) ? throw(DataValueException()) : x.value
+
 get(x::DataValue{Union{}}) = throw(DataValueException())
 get(x::DataValue{Union{}}, y) = y
 

test/runtests.jl

@@ -298,8 +298,9 @@ for T in types
     x3 = DataValue(one(T))
 
     @test_throws DataValueException get(x1)
-    @test get(x2) === zero(T)
-    @test get(x3) === one(T)
+    @test_throws DataValueException x1[]
+    @test get(x2) === x2[] === zero(T)
+    @test get(x3) === x3[] === one(T)
 end
 
 @test_throws DataValueException get(DataValue())