diff --git a/SedRegex/__init__.py b/SedRegex/__init__.py
index 46bc021..8d6cc02 100644
--- a/SedRegex/__init__.py
+++ b/SedRegex/__init__.py
@@ -50,8 +50,10 @@ __url__ = 'https://github.com/jlu5/SupyPlugins'
 
 from . import config
 from . import plugin
-from imp import reload
+from . import constants
+from importlib import reload
 
+reload(constants)
 reload(config)
 reload(plugin)
 
diff --git a/SedRegex/constants.py b/SedRegex/constants.py
new file mode 100755
index 0000000..3610e40
--- /dev/null
+++ b/SedRegex/constants.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+import re
+
+SED_REGEX = re.compile(
+    # This part matches an optional nick followed by ":" or ",", used to direct replacement
+    # at a particular user.
+    r"^(?:(?P<nick>.+?)[:,] )?"
+
+    # Match and save the delimiter (any one symbol) as a named group
+    r"s(?P<delim>[^\w\s])"
+
+    # Match the pattern to replace, which can be any string up to the first instance of the delimiter
+    r"(?P<pattern>(?:(?!(?P=delim)).)*)(?P=delim)"
+
+    # Ditto with the replacement
+    r"(?P<replacement>(?:(?!(?P=delim)).)*)"
+
+    # Optional final delimiter plus flags at the end
+    r"(?:(?P=delim)(?P<flags>[a-z]*))?"
+)
+
+if __name__ == '__main__':
+    print("This is the full regex used by the plugin; paste it into your favourite regex tester "
+          "for debugging:")
+    print(SED_REGEX)
diff --git a/SedRegex/plugin.py b/SedRegex/plugin.py
index 233429b..9cbee97 100644
--- a/SedRegex/plugin.py
+++ b/SedRegex/plugin.py
@@ -1,6 +1,6 @@
 ###
 # Copyright (c) 2015, Michael Daniel Telatynski <postmaster@webdevguru.co.uk>
-# Copyright (c) 2015-2019, James Lu <james@overdrivenetworks.com>
+# Copyright (c) 2015-2020, James Lu <james@overdrivenetworks.com>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -52,8 +52,7 @@ if sys.version_info[0] < 3:
                       'supports Python 2, consult the python2-legacy branch at '
                       'https://github.com/jlu5/SupyPlugins/tree/python2-legacy')
 
-SED_REGEX = re.compile(r"^(?:(?P<nick>.+?)[:,] )?s(?P<delim>[^\w\s])(?P<pattern>.*?)(?P=delim)"
-                       r"(?P<replacement>.*?)(?P=delim)(?P<flags>[a-z]*)$")
+from .constants import *
 
 # Replace newlines and friends with things like literal "\n" (backslash and "n")
 axe_spaces = utils.str.MultipleReplacer({'\n': '\\n', '\t': '\\t', '\r': '\\r'})
diff --git a/SedRegex/test.py b/SedRegex/test.py
index 9300ebb..d45c8c6 100644
--- a/SedRegex/test.py
+++ b/SedRegex/test.py
@@ -1,5 +1,5 @@
 ###
-# Copyright (c) 2017-2019, James Lu <james@overdrivenetworks.com>
+# Copyright (c) 2017-2020, James Lu <james@overdrivenetworks.com>
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -181,6 +181,36 @@ class SedRegexTestCase(ChannelPluginTestCase):
         m = self.getMsg(' ', timeout=1)
         self.assertIn('timed out', str(m))
 
+    def testMissingTrailingSeparator(self):
+        # Allow the plugin to work if you miss the trailing /
+        self.feedMsg('hello world')
+        self.feedMsg('s/world/everyone')
+        m = self.getMsg(' ')
+        self.assertIn('hello everyone', str(m))
+
+        # Make sure it works if there's a space in the replacement
+        self.feedMsg('hello world')
+        self.feedMsg('s@world@how are you')
+        m = self.getMsg(' ')
+        self.assertIn('hello how are you', str(m))
+
+        # Ditto with a space in the original text
+        self.feedMsg("foo bar @ baz")
+        self.feedMsg('s/bar @/and')
+        m = self.getMsg(' ')
+        self.assertIn('foo and baz', str(m))
+
+    def testIgnoreTextAfterTrailingSeparator(self):
+        # https://github.com/jlu5/SupyPlugins/issues/59
+        self.feedMsg('see you ltaer')
+        self.feedMsg('s/ltaer/later/ this text will be ignored')
+        m = self.getMsg(' ')
+        self.assertIn('see you later', str(m))
+
+        self.feedMsg('s/LTAER/later, bye/i <extra text>')
+        m = self.getMsg(' ')
+        self.assertIn('see you later, bye', str(m))
+
     # TODO: test ignores
 
 # vim:set shiftwidth=4 tabstop=4 expandtab textwidth=79: