Add pcre type.

pre_commit/languages/script.py

@@ -1,16 +1,20 @@
 from __future__ import unicode_literals
 
+from pre_commit.languages.helpers import file_args_to_stdin
+
+
 ENVIRONMENT_DIR = None
 
 
 def install_environment(repo_cmd_runner, version='default'):
     """Installation for script type is a noop."""
+    raise AssertionError('Cannot install script repo.')
 
 
 def run_hook(repo_cmd_runner, hook, file_args):
     return repo_cmd_runner.run(
         ['xargs', '{{prefix}}{0}'.format(hook['entry'])] + hook['args'],
         # TODO: this is duplicated in pre_commit/languages/helpers.py
-        stdin='\n'.join(list(file_args) + ['']),
+        stdin=file_args_to_stdin(file_args),
         retcode=None,
     )