Partial interface implementation in groovy

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interface X { void a() void b() } class XAdapter implements X { void a() { println 'default implementation of a' } void b() { println 'default implementation of b' } } def o = [ a: { println 'overridden implementation of a' } ] as XAdapter o.a() o.b()

will output:
overridden implementation of a
default implementation of b

Fun with groovy maps and function call syntax

A function having a Map as first parameter:

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void doIt(Map attrs, Object content) { println attrs println content }

supports equally valid call syntax variations:

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// "classical" call syntax, known from java world doIt([color: 'red', type: 'fruit'], 'hello!') // parentheses can be omitted doIt [color: 'red', type: 'fruit'], 'hello!' // even square brackets for map can be omitted doIt color: 'red', type: 'fruit', 'hello!' // order of map properties does not matter, // map properties can be intermixed with unnamed parameters. doIt color: 'red', 'hello!', type: 'fruit' doIt 'hello!', type: 'fruit', color: 'red'

this effectively allows to implement named parameters in groovy.