Add missing variables function

At some point the uritemplate module added a variables function. This
adds that interface to maintain compatibility.

Closes #26

4 files changed, 30 insertions, 3 deletions

diff --git a/docs/index.rst b/docs/index.rst
index b846d44..35776f0 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -53,6 +53,8 @@ API
 
 .. autofunction:: uritemplate.partial
 
+.. autofunction:: uritemplate.variables
+
 .. autoclass:: uritemplate.URITemplate
     :members:
 
diff --git a/tests/test_uritemplate.py b/tests/test_uritemplate.py
index 26aeb72..b1abc96 100644
--- a/tests/test_uritemplate.py
+++ b/tests/test_uritemplate.py
@@ -1,5 +1,5 @@
 from unittest import TestCase, main
-from uritemplate import URITemplate, expand, partial
+from uritemplate import URITemplate, expand, partial, variables
 from uritemplate import variable
 
 
@@ -580,6 +580,10 @@ class TestAPI(TestCase):
             URITemplate('https://api.github.com/users/sigmavirus24{/other}')
             )
 
+    def test_variables(self):
+        self.assertEqual(variables(self.uri),
+                         URITemplate(self.uri).variable_names)
+
 
 if __name__ == '__main__':
     main()
diff --git a/uritemplate/__init__.py b/uritemplate/__init__.py
index 03abf08..8e76ea5 100644
--- a/uritemplate/__init__.py
+++ b/uritemplate/__init__.py
@@ -19,6 +19,8 @@ __copyright__ = 'Copyright 2013 Ian Cordasco'
 __version__ = '2.0.0rc1'
 __version_info__ = tuple(int(i) for i in __version__.split('.') if i.isdigit())
 
-from uritemplate.api import URITemplate, expand, partial  # noqa: E402
+from uritemplate.api import (
+    URITemplate, expand, partial, variables  # noqa: E402
+)
 
-__all__ = ('URITemplate', 'expand', 'partial')
+__all__ = ('URITemplate', 'expand', 'partial', 'variables')
diff --git a/uritemplate/api.py b/uritemplate/api.py
index cbcec09..37c7c45 100644
--- a/uritemplate/api.py
+++ b/uritemplate/api.py
@@ -50,3 +50,22 @@ def partial(uri, var_dict=None, **kwargs):
 
     """
     return URITemplate(uri).partial(var_dict, **kwargs)
+
+
+def variables(uri):
+    """Parse the variables of the template.
+
+    This returns all of the variable names in the URI Template.
+
+    :returns: Set of variable names
+    :rtype: set
+
+    Example::
+
+        variables('https://api.github.com{/end})
+        # => {'end'}
+        variables('https://api.github.com/repos{/username}{/repository}')
+        # => {'username', 'repository'}
+
+    """
+    return set(URITemplate(uri).variable_names)