Fix matching of dictOf with empty contents (Issue #53)

3 files changed, 24 insertions, 2 deletions

diff --git a/CHANGES b/CHANGES
index 430dd38..c4b95a2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -12,6 +12,9 @@ Version 2.3.1 -
   changes in the tokens returned if you have this condition in your pyparsing
   scripts.
 
+- Fix bug in dictOf which could match an empty sequence, making it
+  infinitely loop if wrapped in a OneOrMore.
+
 - Added unicode sets to pyparsing_unicode for Latin-A and Latin-B ranges.
 
 - Added ability to define custom unicode sets as combinations of other sets
diff --git a/pyparsing.py b/pyparsing.py
index 48e5e23..975846c 100644
--- a/pyparsing.py
+++ b/pyparsing.py
@@ -94,7 +94,7 @@ classes inherit from. Use the docstrings for examples of how to:
 """
 
 __version__ = "2.3.1"
-__versionTime__ = "28 Dec 2018 20:39 UTC"
+__versionTime__ = "28 Dec 2018 20:52 UTC"
 __author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"
 
 import string
@@ -5076,7 +5076,7 @@ def dictOf( key, value ):
         SQUARE
         {'color': 'light blue', 'shape': 'SQUARE', 'posn': 'upper left', 'texture': 'burlap'}
     """
-    return Dict( ZeroOrMore( Group ( key + value ) ) )
+    return Dict(OneOrMore(Group(key + value)))
 
 def originalTextFor(expr, asString=True):
     """Helper to return the original, untokenized text for a given
diff --git a/unitTests.py b/unitTests.py
index cd219bf..9d2731a 100644
--- a/unitTests.py
+++ b/unitTests.py
@@ -3851,6 +3851,25 @@ class ParseResultsWithNameOr(ParseTestCase):
         self.assertEqual(list(expr.parseString('not the bird')['rexp']), 'not the bird'.split())

         self.assertEqual(list(expr.parseString('the bird')['rexp']), 'the bird'.split())

 

+class EmptyDictDoesNotRaiseException(ParseTestCase):

+    def runTest(self):

+        import pyparsing as pp

+

+        key = pp.Word(pp.alphas)

+        value = pp.Word(pp.nums)

+        EQ = pp.Suppress('=')

+        key_value_dict = pp.dictOf(key, EQ + value)

+        try:

+            print(key_value_dict.parseString("""\

+                a = 10

+                b = 20

+                """).dump())

+            print(key_value_dict.parseString("").dump())

+        except pp.ParseException:

+            pass

+        else:

+            self.assertTrue(False, "failed to raise exception when matching empty string")

+

 class MiscellaneousParserTests(ParseTestCase):

     def runTest(self):