OMG we're running a hook

pre_commit/languages/all.py

@@ -0,0 +1,24 @@
+
+from pre_commit.languages import node
+from pre_commit.languages import python
+from pre_commit.languages import ruby
+
+# A language implements the following two functions in its module:
+#
+# def install_environment():
+#     """Installs a repository in the given repository.  Note that the current
+#     working directory will already be inside the repository.
+#     """
+#
+# def run_hook(hook, file_args):
+#     """Runs a hook and returns the returncode and output of running that hook.
+#
+#     Returns:
+#         (returncode, stdout, stderr)
+#     """
+
+languages = {
+    'node': node,
+    'python': python,
+    'ruby': ruby,
+}

pre_commit/languages/node.py

@@ -0,0 +1,7 @@
+
+def install_environment():
+    raise NotImplementedError
+
+
+def run_hook(hook, file_args):
+    raise NotImplementedError

pre_commit/languages/python.py

@@ -0,0 +1,32 @@
+
+import contextlib
+from plumbum import local
+from plumbum.machines.session import ShellSession
+
+PY_ENV = 'py_env'
+
+
+@contextlib.contextmanager
+def in_env():
+    with ShellSession(local['bash'].popen()) as env:
+        env.run('source {0}/bin/activate'.format(PY_ENV))
+        yield env
+
+
+def install_environment():
+    assert local.path('setup.py').exists()
+    # Install a virtualenv
+    local['virtualenv'][PY_ENV]()
+
+    with in_env() as env:
+        # Run their setup.py
+        env.run('pip install .')
+
+
+def run_hook(hook, file_args):
+    with in_env() as env:
+        # TODO: batch filenames
+        return env.run(
+            ' '.join([hook['entry']] + hook.get('args', []) + list(file_args)),
+            retcode=None,
+        )

pre_commit/languages/ruby.py

@@ -0,0 +1,7 @@
+
+def install_environment():
+    raise NotImplementedError
+
+
+def run_hook(hook, file_args):
+    raise NotImplementedError