Fix potential FutureWarning with generated regex; minor reformat of runTests output to break at test comments if any

3 files changed, 35 insertions, 23 deletions

diff --git a/CHANGES b/CHANGES
index 822d220..fa47202 100644
--- a/CHANGES
+++ b/CHANGES
@@ -166,6 +166,12 @@ Version 3.0.0a1
 - Fixed bug in regex definitions for real and sci_real expressions in
   pyparsing_common. Issue #194, reported by Michael Wayne Goodman, thanks!
 
+- Fixed FutureWarning raised beginning in Python 3.7 for Regex expressions
+  containing '[' within a regex set.
+
+- Minor reformatting of output from runTests to make embedded
+  comments more visible.
+
 
 Version 2.4.6 - December, 2019
 ------------------------------
diff --git a/pyparsing/core.py b/pyparsing/core.py
index d9f277c..f24369c 100644
--- a/pyparsing/core.py
+++ b/pyparsing/core.py
@@ -54,7 +54,7 @@ str_type = (str, bytes)
 #
 
 __version__ = "3.0.0a1"
-__versionTime__ = "24 Feb 2020 02:17 UTC"
+__versionTime__ = "30 Mar 2020 00:24 UTC"
 __author__ = "Paul McGuire <ptmcg@users.sourceforge.net>"
 
 
@@ -130,9 +130,12 @@ hexnums = nums + "ABCDEFabcdef"
 alphanums = alphas + nums
 printables = "".join(c for c in string.printable if c not in string.whitespace)
 
+_trim_arity_call_line = None
+
 
 def _trim_arity(func, maxargs=2):
     "decorator to trim function calls to match the arity of the target"
+    global _trim_arity_call_line
 
     if func in singleArgBuiltins:
         return lambda s, l, t: func(t)
@@ -148,11 +151,16 @@ def _trim_arity(func, maxargs=2):
     # synthesize what would be returned by traceback.extract_stack at the call to
     # user's parse action 'func', so that we don't incur call penalty at parse time
 
-    LINE_DIFF = 7
+    LINE_DIFF = 11
     # IF ANY CODE CHANGES, EVEN JUST COMMENTS OR BLANK LINES, BETWEEN THE NEXT LINE AND
     # THE CALL TO FUNC INSIDE WRAPPER, LINE_DIFF MUST BE MODIFIED!!!!
-    this_line = traceback.extract_stack(limit=2)[-1]
-    pa_call_line_synth = (this_line[0], this_line[1] + LINE_DIFF)
+    _trim_arity_call_line = (
+        _trim_arity_call_line or traceback.extract_stack(limit=2)[-1]
+    )
+    pa_call_line_synth = (
+        _trim_arity_call_line[0],
+        _trim_arity_call_line[1] + LINE_DIFF,
+    )
 
     def wrapper(*args):
         nonlocal found_arity, limit
@@ -161,25 +169,23 @@ def _trim_arity(func, maxargs=2):
                 ret = func(*args[limit:])
                 found_arity = True
                 return ret
-            except TypeError:
+            except TypeError as te:
                 # re-raise TypeErrors if they did not come from our arity testing
                 if found_arity:
                     raise
                 else:
-                    try:
-                        tb = sys.exc_info()[-1]
-                        if not extract_tb(tb, limit=2)[-1][:2] == pa_call_line_synth:
-                            raise
-                    finally:
-                        try:
-                            del tb
-                        except NameError:
-                            pass
+                    tb = te.__traceback__
+                    trim_arity_type_error = (
+                        extract_tb(tb, limit=2)[-1][:2] == pa_call_line_synth
+                    )
+                    del tb
 
-                if limit <= maxargs:
-                    limit += 1
-                    continue
-                raise
+                    if trim_arity_type_error:
+                        if limit <= maxargs:
+                            limit += 1
+                            continue
+
+                    raise
 
     # copy func name to wrapper for sensible debug output
     func_name = "<parse action>"
@@ -1655,7 +1661,7 @@ class ParserElement:
                 continue
             if not t:
                 continue
-            out = ["\n".join(comments), t]
+            out = ["\n" + "\n".join(comments) if comments else "", t]
             comments = []
             try:
                 # convert newline marks to actual newlines, and strip leading BOM if present
diff --git a/pyparsing/util.py b/pyparsing/util.py
index a80a6d3..0d5af76 100644
--- a/pyparsing/util.py
+++ b/pyparsing/util.py
@@ -43,7 +43,7 @@ def col(loc, strg):
    Note: the default parsing behavior is to expand tabs in the input string
    before starting the parsing process.  See
    :class:`ParserElement.parseString` for more
-   information on parsing strings containing ``<TAB>``\ s, and suggested
+   information on parsing strings containing ``<TAB>`` s, and suggested
    methods to maintain a consistent view of the parsed string, the parse
    location, and line and column positions within the parsed string.
    """
@@ -57,7 +57,7 @@ def lineno(loc, strg):
 
     Note - the default parsing behavior is to expand tabs in the input string
     before starting the parsing process.  See :class:`ParserElement.parseString`
-    for more information on parsing strings containing ``<TAB>``\ s, and
+    for more information on parsing strings containing ``<TAB>`` s, and
     suggested methods to maintain a consistent view of the parsed string, the
     parse location, and line and column positions within the parsed string.
     """
@@ -126,8 +126,8 @@ class _FifoCache:
 
 
 def _escapeRegexRangeChars(s):
-    # ~  escape these chars: ^-]
-    for c in r"\^-]":
+    # escape these chars: ^-[]
+    for c in r"\^-[]":
         s = s.replace(c, _bslash + c)
     s = s.replace("\n", r"\n")
     s = s.replace("\t", r"\t")