Selected backports from 3.0.0 work

4 files changed, 90 insertions, 20 deletions

diff --git a/CHANGES b/CHANGES
index 11a5a36..950945b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,15 @@
 Change Log
 ==========
 
+Version 2.4.7 - March, 2020
+---------------------------
+- Backport of selected fixes from 3.0.0 work:
+  . Each bug with Regex expressions
+  . And expressions not properly constructing with generator
+  . Traceback abbreviation
+  . Bug in delta_time example
+
+
 Version 2.4.6 - December, 2019
 ------------------------------
 - Fixed typos in White mapping of whitespace characters, to use
diff --git a/examples/delta_time.py b/examples/delta_time.py
index e079094..525f5df 100644
--- a/examples/delta_time.py
+++ b/examples/delta_time.py
@@ -52,6 +52,9 @@ today, tomorrow, yesterday, noon, midnight, now = map(CK, "today tomorrow yester
 def plural(s):
     return CK(s) | CK(s + 's').addParseAction(pp.replaceWith(s))
 week, day, hour, minute, second = map(plural, "week day hour minute second".split())
+time_units = hour | minute | second
+any_time_units = week | day | time_units
+
 am = CL("am")
 pm = CL("pm")
 COLON = pp.Suppress(':')
@@ -69,7 +72,7 @@ on_ = CK("on")
 couple = (pp.Optional(CK("a")) + CK("couple") + pp.Optional(CK("of"))).setParseAction(pp.replaceWith(2))
 a_qty = (CK("a") | CK("an")).setParseAction(pp.replaceWith(1))
 the_qty = CK("the").setParseAction(pp.replaceWith(1))
-qty = pp.ungroup(integer | couple | a_qty | the_qty)
+qty = pp.ungroup(integer | couple | a_qty | the_qty).setName("qty")
 time_ref_present = pp.Empty().addParseAction(pp.replaceWith(True))('time_ref_present')
 
 def fill_24hr_time_fields(t):
@@ -86,8 +89,10 @@ def fill_default_time_fields(t):
 weekday_name_list = list(calendar.day_name)
 weekday_name = pp.oneOf(weekday_name_list)
 
-_24hour_time = pp.Word(pp.nums, exact=4).addParseAction(lambda t: [int(t[0][:2]),int(t[0][2:])],
-                                                        fill_24hr_time_fields)
+_24hour_time = (~(integer + any_time_units)
+                + pp.Word(pp.nums, exact=4).addParseAction(lambda t: [int(t[0][:2]),int(t[0][2:])],
+                                                           fill_24hr_time_fields)
+                )
 _24hour_time.setName("0000 time")
 ampm = am | pm
 timespec = (integer("HH")
@@ -302,6 +307,10 @@ if __name__ == "__main__":
         2pm next Sunday
         next Sunday at 2pm
         last Sunday at 2pm
+        10 seconds ago
+        100 seconds ago
+        1000 seconds ago
+        10000 seconds ago
     """
 
     time_of_day = timedelta(hours=current_time.hour,
@@ -309,6 +318,10 @@ if __name__ == "__main__":
                             seconds=current_time.second)
     expected = {
         'now' : timedelta(0),
+        "10 seconds ago": timedelta(seconds=-10),
+        "100 seconds ago": timedelta(seconds=-100),
+        "1000 seconds ago": timedelta(seconds=-1000),
+        "10000 seconds ago": timedelta(seconds=-10000),
         '10 minutes ago': timedelta(minutes=-10),
         '10 minutes from now': timedelta(minutes=10),
         'in 10 minutes': timedelta(minutes=10),
diff --git a/pyparsing.py b/pyparsing.py
index 4d2f98e..135b6a0 100644
--- a/pyparsing.py
+++ b/pyparsing.py
@@ -95,8 +95,8 @@ classes inherit from. Use the docstrings for examples of how to:
    namespace class
 """
 
-__version__ = "2.4.6"
-__versionTime__ = "24 Dec 2019 04:27 UTC"
+__version__ = "2.4.7"
+__versionTime__ = "04 Mar 2020 02:48 UTC"
 __author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"
 
 import string
@@ -1391,6 +1391,12 @@ class ParserElement(object):
         """
         ParserElement._literalStringClass = cls
 
+    @classmethod
+    def _trim_traceback(cls, tb):
+        while tb.tb_next:
+            tb = tb.tb_next
+        return tb
+
     def __init__(self, savelist=False):
         self.parseAction = list()
         self.failAction = None
@@ -1943,7 +1949,8 @@ class ParserElement(object):
             if ParserElement.verbose_stacktrace:
                 raise
             else:
-                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
+                exc.__traceback__ = self._trim_traceback(exc.__traceback__)
                 raise exc
         else:
             return tokens
@@ -2017,7 +2024,8 @@ class ParserElement(object):
             if ParserElement.verbose_stacktrace:
                 raise
             else:
-                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
+                exc.__traceback__ = self._trim_traceback(exc.__traceback__)
                 raise exc
 
     def transformString(self, instring):
@@ -2063,7 +2071,8 @@ class ParserElement(object):
             if ParserElement.verbose_stacktrace:
                 raise
             else:
-                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
+                exc.__traceback__ = self._trim_traceback(exc.__traceback__)
                 raise exc
 
     def searchString(self, instring, maxMatches=_MAX_INT):
@@ -2093,7 +2102,8 @@ class ParserElement(object):
             if ParserElement.verbose_stacktrace:
                 raise
             else:
-                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
+                exc.__traceback__ = self._trim_traceback(exc.__traceback__)
                 raise exc
 
     def split(self, instring, maxsplit=_MAX_INT, includeSeparators=False):
@@ -2565,7 +2575,8 @@ class ParserElement(object):
             if ParserElement.verbose_stacktrace:
                 raise
             else:
-                # catch and re-raise exception from here, clears out pyparsing internal stack trace
+                # catch and re-raise exception from here, clearing out pyparsing internal stack trace
+                exc.__traceback__ = self._trim_traceback(exc.__traceback__)
                 raise exc
 
     def __eq__(self, other):
@@ -3312,7 +3323,7 @@ class Regex(Token):
         self.name = _ustr(self)
         self.errmsg = "Expected " + self.name
         self.mayIndexError = False
-        self.mayReturnEmpty = True
+        self.mayReturnEmpty = self.re_match("") is not None
         self.asGroupList = asGroupList
         self.asMatch = asMatch
         if self.asGroupList:
@@ -3993,6 +4004,7 @@ class And(ParseExpression):
             self.leaveWhitespace()
 
     def __init__(self, exprs, savelist=True):
+        exprs = list(exprs)
         if exprs and Ellipsis in exprs:
             tmp = []
             for i, expr in enumerate(exprs):
@@ -4358,7 +4370,7 @@ class Each(ParseExpression):
         if self.initExprGroups:
             self.opt1map = dict((id(e.expr), e) for e in self.exprs if isinstance(e, Optional))
             opt1 = [e.expr for e in self.exprs if isinstance(e, Optional)]
-            opt2 = [e for e in self.exprs if e.mayReturnEmpty and not isinstance(e, Optional)]
+            opt2 = [e for e in self.exprs if e.mayReturnEmpty and not isinstance(e, (Optional, Regex))]
             self.optionals = opt1 + opt2
             self.multioptionals = [e.expr for e in self.exprs if isinstance(e, ZeroOrMore)]
             self.multirequired = [e.expr for e in self.exprs if isinstance(e, OneOrMore)]
diff --git a/unitTests.py b/unitTests.py
index 3508394..cd9406e 100644
--- a/unitTests.py
+++ b/unitTests.py
@@ -2845,14 +2845,28 @@ class OptionalEachTest(ParseTestCase):
     def runTest1(self):
         from pyparsing import Optional, Keyword
 
-        the_input = "Major Tal Weiss"
-        parser1 = (Optional('Tal') + Optional('Weiss')) & Keyword('Major')
-        parser2 = Optional(Optional('Tal') + Optional('Weiss')) & Keyword('Major')
-        p1res = parser1.parseString( the_input)
-        p2res = parser2.parseString( the_input)
-        self.assertEqual(p1res.asList(), p2res.asList(),
-                         "Each failed to match with nested Optionals, "
-                         + str(p1res.asList()) + " should match " + str(p2res.asList()))
+        for the_input in [
+            "Tal Weiss Major",
+            "Tal Major",
+            "Weiss Major",
+            "Major",
+            "Major Tal",
+            "Major Weiss",
+            "Major Tal Weiss",
+        ]:
+            print_(the_input)
+            parser1 = (Optional("Tal") + Optional("Weiss")) & Keyword("Major")
+            parser2 = Optional(Optional("Tal") + Optional("Weiss")) & Keyword("Major")
+            p1res = parser1.parseString(the_input)
+            p2res = parser2.parseString(the_input)
+            self.assertEqual(
+                p1res.asList(),
+                p2res.asList(),
+                "Each failed to match with nested Optionals, "
+                + str(p1res.asList())
+                + " should match "
+                + str(p2res.asList()),
+            )
 
     def runTest2(self):
         from pyparsing import Word, alphanums, OneOrMore, Group, Regex, Optional
@@ -2906,12 +2920,34 @@ class OptionalEachTest(ParseTestCase):
             42
             """)
 
+    def testParseExpressionsWithRegex(self):
+        from itertools import product
+        match_empty_regex = pp.Regex(r"[a-z]*")
+        match_nonempty_regex = pp.Regex(r"[a-z]+")
+
+        parser_classes = pp.ParseExpression.__subclasses__()
+        test_string = "abc def"
+        expected = ["abc"]
+        for expr, cls in product((match_nonempty_regex, match_empty_regex), parser_classes):
+            print_(expr, cls)
+            parser = cls([expr])
+            parsed_result = parser.parseString(test_string)
+            print_(parsed_result.dump())
+            self.assertParseResultsEquals(parsed_result, expected)
+
+        for expr, cls in product((match_nonempty_regex, match_empty_regex), (pp.MatchFirst, pp.Or)):
+            parser = cls([expr, expr])
+            print_(parser)
+            parsed_result = parser.parseString(test_string)
+            print_(parsed_result.dump())
+            self.assertParseResultsEquals(parsed_result, expected)
 
     def runTest(self):
         self.runTest1()
         self.runTest2()
         self.runTest3()
         self.runTest4()
+        self.testParseExpressionsWithRegex()
 
 class SumParseResultsTest(ParseTestCase):
     def runTest(self):