From 0c1cf0bc8e4c272eacff896eaea5b3d0e03776c7 Mon Sep 17 00:00:00 2001
From: Thomas Mansencal <thomas.mansencal@gmail.com>
Date: Sat, 16 Apr 2016 21:15:31 +1200
Subject: [PATCH] Add "colour.utilities.metadata.set_decorator" decorator.

---
 colour/utilities/__init__.py             |  6 ++-
 colour/utilities/metadata.py             | 60 +++++++++++++++++++++++-
 colour/utilities/tests/tests_metadata.py | 32 ++++++++++++-
 3 files changed, 92 insertions(+), 6 deletions(-)

diff --git a/colour/utilities/__init__.py b/colour/utilities/__init__.py
index dfe95c4591..81994c0a06 100644
--- a/colour/utilities/__init__.py
+++ b/colour/utilities/__init__.py
@@ -20,7 +20,8 @@
     Metadata,
     UnitMetadata,
     CallableMetadata,
-    FunctionMetadata)
+    FunctionMetadata,
+    set_metadata)
 from .array import (
     as_numeric,
     closest,
@@ -55,7 +56,8 @@
 __all__ += ['Metadata',
             'UnitMetadata',
             'CallableMetadata',
-            'FunctionMetadata']
+            'FunctionMetadata',
+            'set_metadata']
 __all__ += ['as_numeric',
             'closest',
             'normalise_maximum',
diff --git a/colour/utilities/metadata.py b/colour/utilities/metadata.py
index e01acb58ed..13fd375392 100644
--- a/colour/utilities/metadata.py
+++ b/colour/utilities/metadata.py
@@ -11,10 +11,12 @@
 -   :class:`UnitMetadata`
 -   :class:`CallableMetadata`
 -   :class:`FunctionMetadata`
+-   :def:`set_metadata`
 """
 
 from __future__ import division, unicode_literals
 
+import functools
 from weakref import WeakValueDictionary
 
 import colour  # noqa
@@ -29,7 +31,8 @@
 __all__ = ['Metadata',
            'UnitMetadata',
            'CallableMetadata',
-           'FunctionMetadata']
+           'FunctionMetadata',
+           'set_metadata']
 
 
 class Metadata(object):
@@ -56,8 +59,8 @@ class Metadata(object):
     Attributes
     ----------
     family
-    index
     instances
+    index
     name
     strict_name
 
@@ -702,3 +705,56 @@ def __repr__(self):
             self.strict_method)
 
         return text
+
+
+def set_metadata(metadata, *args, **kwargs):
+    """
+    Decorator setting given metadata to decorated object.
+
+    Parameters
+    ----------
+    \*args : list, optional
+        Arguments.
+    \**kwargs : dict, optional
+        Keywords arguments.
+
+    Returns
+    -------
+    object
+
+    Examples
+    --------
+    >>> @set_metadata(Metadata, 'Lambda', '$\Lambda$')
+    ... def f():
+    ...     pass
+    >>> f.__metadata__
+    Metadata('Lambda', '$\Lambda$')
+    >>> m = Metadata('Gamma', '$\Gamma$')
+    >>> @set_metadata(m)
+    ... def f():
+    ...     pass
+    >>> f.__metadata__
+    Metadata('Gamma', '$\Gamma$')
+    """
+
+    if not isinstance(metadata, Metadata):
+        metadata = metadata(*args, **kwargs)
+
+    def wrapper(function):
+        """
+        Wrapper for given function.
+        """
+
+        function.__metadata__ = metadata
+
+        @functools.wraps(function)
+        def wrapped(*args, **kwargs):
+            """
+            Wrapped function.
+            """
+
+            return function(*args, **kwargs)
+
+        return wrapped
+
+    return wrapper
diff --git a/colour/utilities/tests/tests_metadata.py b/colour/utilities/tests/tests_metadata.py
index d883e6745d..a7bacdc1c9 100644
--- a/colour/utilities/tests/tests_metadata.py
+++ b/colour/utilities/tests/tests_metadata.py
@@ -13,7 +13,8 @@
     Metadata,
     UnitMetadata,
     CallableMetadata,
-    FunctionMetadata)
+    FunctionMetadata,
+    set_metadata)
 
 __author__ = 'Colour Developers'
 __copyright__ = 'Copyright (C) 2013 - 2015 - Colour Developers'
@@ -25,7 +26,8 @@
 __all__ = ['TestMetadata',
            'TestUnitMetadata',
            'TestCallableMetadata',
-           'TestFunctionMetadata']
+           'TestFunctionMetadata',
+           'TestSetMetadata']
 
 
 class TestMetadata(unittest.TestCase):
@@ -210,5 +212,31 @@ def test__repr__(self):
 UnitMetadata('Lightness', '$L^\star$'), 'CIE 1976', '$CIE 1976$')")
 
 
+class TestSetMetadata(unittest.TestCase):
+    """
+    Defines :func:`colour.utilities.metadata.set_metadata` definition units
+    tests methods.
+    """
+
+    def test_set_metadata(self):
+        """
+        Tests :func:`colour.utilities.metadata.set_metadata` definition.
+        """
+
+        @set_metadata(Metadata, 'Lambda', '$\Lambda$')
+        def f():
+            pass
+
+        self.assertTrue(hasattr(f, '__metadata__'))
+
+        m = Metadata('Gamma', '$\Gamma$')
+
+        @set_metadata(m)
+        def f():
+            pass
+
+        self.assertIs(f.__metadata__, m)
+
+
 if __name__ == '__main__':
     unittest.main()