Move specialcasing of words() to any subclass of Future

The idea here is that plugins might want to provide some other optimization we
haven't dreamed up yet, and to do so this way means they don't need to change
with RegexLexerMeta (and it will be easier to support in regexlint).

1 files changed, 12 insertions, 0 deletions

diff --git a/pygments/util.py b/pygments/util.py
index 3a1c0947..6f0c4148 100644
--- a/pygments/util.py
+++ b/pygments/util.py
@@ -276,6 +276,18 @@ def format_lines(var_name, seq, raw=False, indent_level=0):
     lines.append(base_indent + ')')
     return '\n'.join(lines)
 
+
+class Future(object):
+    """
+    Generic class to defer some work.
+
+    Handled specially in RegexLexerMeta, to support regex string construction at
+    first use.
+    """
+    def get(self):
+        raise NotImplementedError
+
+
 # Python 2/3 compatibility
 
 if sys.version_info < (3, 0):