evaluate re.compile lazily

1 files changed, 2 insertions, 1 deletions

diff --git a/constructor.py b/constructor.py
index 9706bbe..7769874 100644
--- a/constructor.py
+++ b/constructor.py
@@ -26,6 +26,7 @@ from ruamel.yaml.scalarstring import (PreservedScalarString, SingleQuotedScalarS
 from ruamel.yaml.scalarint import ScalarInt, BinaryInt, OctalInt, HexInt, HexCapsInt
 from ruamel.yaml.scalarfloat import ScalarFloat
 from ruamel.yaml.timestamp import TimeStamp
+from ruamel.yaml.util import RegExp
 
 if False:  # MYPY
     from typing import Any, Dict, List, Set, Generator  # NOQA
@@ -471,7 +472,7 @@ class SafeConstructor(BaseConstructor):
                     None, None,
                     "failed to decode base64 data: %s" % exc, node.start_mark)
 
-    timestamp_regexp = re.compile(
+    timestamp_regexp = RegExp(
         u'''^(?P<year>[0-9][0-9][0-9][0-9])
           -(?P<month>[0-9][0-9]?)
           -(?P<day>[0-9][0-9]?)