evaluate re.compile lazily

5 files changed, 56 insertions, 29 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]?)
diff --git a/reader.py b/reader.py
index 9ad2b5f..705d6d7 100644
--- a/reader.py
+++ b/reader.py
@@ -25,6 +25,7 @@ import re
 
 from ruamel.yaml.error import YAMLError, FileMark, StringMark, YAMLStreamError
 from ruamel.yaml.compat import text_type, binary_type, PY3
+from ruamel.yaml.util import RegExp
 
 if False:  # MYPY
     from typing import Any, Dict, Optional, List, Union, Text  # NOQA
@@ -181,22 +182,24 @@ class Reader(object):
 
     # 4 if 32 bit unicode supported, 2 e.g. on MacOS (issue 56)
     try:
-        NON_PRINTABLE = re.compile(
+        re.compile(u'[^\U00010000]')
+    except:
+        NON_PRINTABLE = RegExp(
             u'[^\x09\x0A\x0D\x20-\x7E\x85'
             u'\xA0-\uD7FF'
             u'\uE000-\uFFFD'
-            u'\U00010000-\U0010FFFF'
             u']'
         )
-        UNICODE_SIZE = 4
-    except:
-        NON_PRINTABLE = re.compile(
+        UNICODE_SIZE = 2
+    else:
+        NON_PRINTABLE = RegExp(
             u'[^\x09\x0A\x0D\x20-\x7E\x85'
             u'\xA0-\uD7FF'
             u'\uE000-\uFFFD'
+            u'\U00010000-\U0010FFFF'
             u']'
         )
-        UNICODE_SIZE = 2
+        UNICODE_SIZE = 4
 
     def check_printable(self, data):
         # type: (Any) -> None
diff --git a/resolver.py b/resolver.py
index 85e640d..9e5d320 100644
--- a/resolver.py
+++ b/resolver.py
@@ -11,6 +11,7 @@ if False:  # MYPY
 from ruamel.yaml.compat import string_types, _DEFAULT_YAML_VERSION  # NOQA
 from ruamel.yaml.error import *                               # NOQA
 from ruamel.yaml.nodes import *                               # NOQA
+from ruamel.yaml.util import RegExp  # NOQA
 
 __all__ = ['BaseResolver', 'Resolver', 'VersionedResolver']
 
@@ -23,17 +24,17 @@ __all__ = ['BaseResolver', 'Resolver', 'VersionedResolver']
 implicit_resolvers = [
     ([(1, 2)],
         u'tag:yaml.org,2002:bool',
-        re.compile(u'''^(?:true|True|TRUE|false|False|FALSE)$''', re.X),
+        RegExp(u'''^(?:true|True|TRUE|false|False|FALSE)$''', re.X),
         list(u'tTfF')),
     ([(1, 1)],
         u'tag:yaml.org,2002:bool',
-        re.compile(u'''^(?:yes|Yes|YES|no|No|NO
+        RegExp(u'''^(?:yes|Yes|YES|no|No|NO
         |true|True|TRUE|false|False|FALSE
         |on|On|ON|off|Off|OFF)$''', re.X),
         list(u'yYnNtTfFoO')),
     ([(1, 2)],
         u'tag:yaml.org,2002:float',
-        re.compile(u'''^(?:
+        RegExp(u'''^(?:
          [-+]?(?:[0-9][0-9_]*)\\.[0-9_]*(?:[eE][-+]?[0-9]+)?
         |[-+]?(?:[0-9][0-9_]*)(?:[eE][-+]?[0-9]+)
         |\\.[0-9_]+(?:[eE][-+][0-9]+)?
@@ -42,7 +43,7 @@ implicit_resolvers = [
         list(u'-+0123456789.')),
     ([(1, 1)],
         u'tag:yaml.org,2002:float',
-        re.compile(u'''^(?:
+        RegExp(u'''^(?:
          [-+]?(?:[0-9][0-9_]*)\\.[0-9_]*(?:[eE][-+]?[0-9]+)?
         |[-+]?(?:[0-9][0-9_]*)(?:[eE][-+]?[0-9]+)
         |\\.[0-9_]+(?:[eE][-+][0-9]+)?
@@ -52,14 +53,14 @@ implicit_resolvers = [
         list(u'-+0123456789.')),
     ([(1, 2)],
         u'tag:yaml.org,2002:int',
-        re.compile(u'''^(?:[-+]?0b[0-1_]+
+        RegExp(u'''^(?:[-+]?0b[0-1_]+
         |[-+]?0o?[0-7_]+
         |[-+]?(?:0|[1-9][0-9_]*)
         |[-+]?0x[0-9a-fA-F_]+)$''', re.X),
         list(u'-+0123456789')),
     ([(1, 1)],
         u'tag:yaml.org,2002:int',
-        re.compile(u'''^(?:[-+]?0b[0-1_]+
+        RegExp(u'''^(?:[-+]?0b[0-1_]+
         |[-+]?0?[0-7_]+
         |[-+]?(?:0|[1-9][0-9_]*)
         |[-+]?0x[0-9a-fA-F_]+
@@ -67,17 +68,17 @@ implicit_resolvers = [
         list(u'-+0123456789')),
     ([(1, 2), (1, 1)],
         u'tag:yaml.org,2002:merge',
-        re.compile(u'^(?:<<)$'),
+        RegExp(u'^(?:<<)$'),
         [u'<']),
     ([(1, 2), (1, 1)],
         u'tag:yaml.org,2002:null',
-        re.compile(u'''^(?: ~
+        RegExp(u'''^(?: ~
         |null|Null|NULL
         | )$''', re.X),
         [u'~', u'n', u'N', u'']),
     ([(1, 2), (1, 1)],
         u'tag:yaml.org,2002:timestamp',
-        re.compile(u'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
+        RegExp(u'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
         |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
         (?:[Tt]|[ \\t]+)[0-9][0-9]?
         :[0-9][0-9] :[0-9][0-9] (?:\\.[0-9]*)?
@@ -85,13 +86,13 @@ implicit_resolvers = [
         list(u'0123456789')),
     ([(1, 2), (1, 1)],
         u'tag:yaml.org,2002:value',
-        re.compile(u'^(?:=)$'),
+        RegExp(u'^(?:=)$'),
         [u'=']),
     # The following resolver is only for documentation purposes. It cannot work
     # because plain scalars cannot start with '!', '&', or '*'.
     ([(1, 2), (1, 1)],
         u'tag:yaml.org,2002:yaml',
-        re.compile(u'^(?:!|&|\\*)$'),
+        RegExp(u'^(?:!|&|\\*)$'),
         list(u'!&*')),
 ]
 
@@ -308,14 +309,14 @@ class Resolver(BaseResolver):
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:bool',
-    re.compile(u'''^(?:yes|Yes|YES|no|No|NO
+    RegExp(u'''^(?:yes|Yes|YES|no|No|NO
     |true|True|TRUE|false|False|FALSE
     |on|On|ON|off|Off|OFF)$''', re.X),
     list(u'yYnNtTfFoO'))
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:float',
-    re.compile(u'''^(?:
+    RegExp(u'''^(?:
      [-+]?(?:[0-9][0-9_]*)\\.[0-9_]*(?:[eE][-+]?[0-9]+)?
     |[-+]?(?:[0-9][0-9_]*)(?:[eE][-+]?[0-9]+)
     |\\.[0-9_]+(?:[eE][-+][0-9]+)?
@@ -326,7 +327,7 @@ Resolver.add_implicit_resolver_base(
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:int',
-    re.compile(u'''^(?:[-+]?0b[0-1_]+
+    RegExp(u'''^(?:[-+]?0b[0-1_]+
     |[-+]?0o?[0-7_]+
     |[-+]?(?:0|[1-9][0-9_]*)
     |[-+]?0x[0-9a-fA-F_]+
@@ -335,19 +336,19 @@ Resolver.add_implicit_resolver_base(
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:merge',
-    re.compile(u'^(?:<<)$'),
+    RegExp(u'^(?:<<)$'),
     [u'<'])
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:null',
-    re.compile(u'''^(?: ~
+    RegExp(u'''^(?: ~
     |null|Null|NULL
     | )$''', re.X),
     [u'~', u'n', u'N', u''])
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:timestamp',
-    re.compile(u'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
+    RegExp(u'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
     |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
     (?:[Tt]|[ \\t]+)[0-9][0-9]?
     :[0-9][0-9] :[0-9][0-9] (?:\\.[0-9]*)?
@@ -356,14 +357,14 @@ Resolver.add_implicit_resolver_base(
 
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:value',
-    re.compile(u'^(?:=)$'),
+    RegExp(u'^(?:=)$'),
     [u'='])
 
 # The following resolver is only for documentation purposes. It cannot work
 # because plain scalars cannot start with '!', '&', or '*'.
 Resolver.add_implicit_resolver_base(
     u'tag:yaml.org,2002:yaml',
-    re.compile(u'^(?:!|&|\\*)$'),
+    RegExp(u'^(?:!|&|\\*)$'),
     list(u'!&*'))
 
 
diff --git a/serializer.py b/serializer.py
index 46884b5..d6012db 100644
--- a/serializer.py
+++ b/serializer.py
@@ -2,10 +2,9 @@
 
 from __future__ import absolute_import
 
-import re
-
 from ruamel.yaml.error import YAMLError
 from ruamel.yaml.compat import nprint, DBG_NODE, dbg, string_types
+from ruamel.yaml.util import RegExp
 
 from ruamel.yaml.events import (
     StreamStartEvent, StreamEndEvent, MappingStartEvent, MappingEndEvent,
@@ -31,7 +30,7 @@ class Serializer(object):
 
     # 'id' and 3+ numbers, but not 000
     ANCHOR_TEMPLATE = u'id%03d'
-    ANCHOR_RE = re.compile(u'id(?!000$)\\d{3,}')
+    ANCHOR_RE = RegExp(u'id(?!000$)\\d{3,}')
 
     def __init__(self, encoding=None, explicit_start=None, explicit_end=None,
                  version=None, tags=None, dumper=None):
diff --git a/util.py b/util.py
index 9f939cf..077b264 100644
--- a/util.py
+++ b/util.py
@@ -6,6 +6,9 @@ some helper functions that might be generally useful
 
 from __future__ import absolute_import, print_function
 
+from functools import partial
+import re
+
 from .compat import text_type, binary_type
 
 if False:  # MYPY
@@ -13,6 +16,26 @@ if False:  # MYPY
     from .compat import StreamTextType  # NOQA
 
 
+class LazyEval(object):
+    def __init__(self, func, *args, **kwargs):
+        def lazy_self():
+            return_value = func(*args, **kwargs)
+            object.__setattr__(self, "lazy_self", lambda: return_value)
+            return return_value
+        object.__setattr__(self, "lazy_self", lazy_self)
+
+    def __getattribute__(self, name):
+        lazy_self = object.__getattribute__(self, "lazy_self")
+        if name == "lazy_self":
+            return lazy_self
+        return getattr(lazy_self(), name)
+
+    def __setattr__(self, name, value):
+        setattr(self.lazy_self(), name, value)
+
+
+RegExp = partial(LazyEval, re.compile)
+
 # originally as comment
 # https://github.com/pre-commit/pre-commit/pull/211#issuecomment-186466605
 # if you use this in your code, I suggest adding a test in your test suite