--------------------------
- NOTE: Deprecated functions and features that will be dropped
in pyparsing 2.5.0 (planned next release):
. support for Python 2 - ongoing users running with
Python 2 can continue to use pyparsing 2.4.1
. ParseResults.asXML() - if used for debugging, switch
to using ParseResults.dump(); if used for data transfer,
use ParseResults.asDict() to convert to a nested Python
dict, which can then be converted to XML or JSON or
other transfer format
. operatorPrecedence synonym for infixNotation -
convert to calling infixNotation
. commaSeparatedList - convert to using
pyparsing_common.comma_separated_list
. upcaseTokens and downcaseTokens - convert to using
pyparsing_common.upcaseTokens and downcaseTokens
. __compat__.collect_all_And_tokens will not be settable to
False to revert to pre-2.3.1 results name behavior -
review use of names for MatchFirst and Or expressions
containing And expressions, as they will return the
complete list of parsed tokens, not just the first one.
Use __diag__.warn_multiple_tokens_in_named_alternation
(described below) to help identify those expressions
in your parsers that will have changed as a result.
- A new shorthand notation has been added for repetition
expressions: expr[min, max], with '...' valid as a min
or max value:
- expr[...] is equivalent to OneOrMore(expr)
- expr[0, ...] is equivalent to ZeroOrMore(expr)
- expr[1, ...] is equivalent to OneOrMore(expr)
- expr[n, ...] or expr[n,] is equivalent
to expr*n + ZeroOrMore(expr)
(read as "n or more instances of expr")
- expr[..., n] is equivalent to expr*(0, n)
- expr[m, n] is equivalent to expr*(m, n)
Note that expr[..., n] and expr[m, n] do not raise an exception
if more than n exprs exist in the input stream. If this
behavior is desired, then write expr[..., n] + ~expr.
- '...' can also be used as short hand for SkipTo when used
in adding parse expressions to compose an And expression.
Literal('start') + ... + Literal('end')
And(['start', ..., 'end'])
are both equivalent to:
Literal('start') + SkipTo('end')("_skipped*") + Literal('end')
The '...' form has the added benefit of not requiring repeating
the skip target expression. Note that the skipped text is
returned with '_skipped' as a results name, and that the contents of
`_skipped` will contain a list of text from all `...`s in the expression.
- '...' can also be used as a "skip forward in case of error" expression:
expr = "start" + (Word(nums).setName("int") | ...) + "end"
expr.parseString("start 456 end")
['start', '456', 'end']
expr.parseString("start 456 foo 789 end")
['start', '456', 'foo 789 ', 'end']
- _skipped: ['foo 789 ']
expr.parseString("start foo end")
['start', 'foo ', 'end']
- _skipped: ['foo ']
expr.parseString("start end")
['start', '', 'end']
- _skipped: ['missing <int>']
Note that in all the error cases, the '_skipped' results name is
present, showing a list of the extra or missing items.
This form is only valid when used with the '|' operator.
- Improved exception messages to show what was actually found, not
just what was expected.
word = pp.Word(pp.alphas)
pp.OneOrMore(word).parseString("aaa bbb 123", parseAll=True)
Former exception message:
pyparsing.ParseException: Expected end of text (at char 8), (line:1, col:9)
New exception message:
pyparsing.ParseException: Expected end of text, found '1' (at char 8), (line:1, col:9)
- Added diagnostic switches to help detect and warn about common
parser construction mistakes, or enable additional parse
debugging. Switches are attached to the pyparsing.__diag__
namespace object:
- warn_multiple_tokens_in_named_alternation - flag to enable warnings when a results
name is defined on a MatchFirst or Or expression with one or more And subexpressions
(default=True)
- warn_ungrouped_named_tokens_in_collection - flag to enable warnings when a results
name is defined on a containing expression with ungrouped subexpressions that also
have results names (default=True)
- warn_name_set_on_empty_Forward - flag to enable warnings when a Forward is defined
with a results name, but has no contents defined (default=False)
- warn_on_multiple_string_args_to_oneof - flag to enable warnings when oneOf is
incorrectly called with multiple str arguments (default=True)
- enable_debug_on_named_expressions - flag to auto-enable debug on all subsequent
calls to ParserElement.setName() (default=False)
warn_multiple_tokens_in_named_alternation is intended to help
those who currently have set __compat__.collect_all_And_tokens to
False as a workaround for using the pre-2.3.1 code with named
MatchFirst or Or expressions containing an And expression.
- Added ParseResults.from_dict classmethod, to simplify creation
of a ParseResults with results names using a dict, which may be nested.
This makes it easy to add a sub-level of named items to the parsed
tokens in a parse action.
- Added asKeyword argument (default=False) to oneOf, to force
keyword-style matching on the generated expressions.
- ParserElement.runTests now accepts an optional 'file' argument to
redirect test output to a file-like object (such as a StringIO,
or opened file). Default is to write to sys.stdout.
- conditionAsParseAction is a helper method for constructing a
parse action method from a predicate function that simply
returns a boolean result. Useful for those places where a
predicate cannot be added using addCondition, but must be
converted to a parse action (such as in infixNotation). May be
used as a decorator if default message and exception types
can be used. See ParserElement.addCondition for more details
about the expected signature and behavior for predicate condition
methods.
- While investigating issue 93, I found that Or and
addCondition could interact to select an alternative that
is not the longest match. This is because Or first checks
all alternatives for matches without running attached
parse actions or conditions, orders by longest match, and
then rechecks for matches with conditions and parse actions.
Some expressions, when checking with conditions, may end
up matching on a shorter token list than originally matched,
but would be selected because of its original priority.
This matching code has been expanded to do more extensive
searching for matches when a second-pass check matches a
smaller list than in the first pass.
- Fixed issue 87, a regression in indented block.
Reported by Renz Bagaporo, who submitted a very nice repro
example, which makes the bug-fixing process a lot easier,
thanks!
- Fixed MemoryError issue 85 and 91 with str generation for
Forwards. Thanks decalage2 and Harmon758 for your patience.
- Modified setParseAction to accept None as an argument,
indicating that all previously-defined parse actions for the
expression should be cleared.
- Modified pyparsing_common.real and sci_real to parse reals
without leading integer digits before the decimal point,
consistent with Python real number formats. Original PR 98
submitted by ansobolev.
- Modified runTests to call postParse function before dumping out
the parsed results - allows for postParse to add further results,
such as indications of additional validation success/failure.
- Updated statemachine example: refactored state transitions to use
overridden classmethods; added <statename>Mixin class to simplify
definition of application classes that "own" the state object and
delegate to it to model state-specific properties and behavior.
- Added example nested_markup.py, showing a simple wiki markup with
nested markup directives, and illustrating the use of '...' for
skipping over input to match the next expression. (This example
uses syntax that is not valid under Python 2.)
- Rewrote delta_time.py example (renamed from deltaTime.py) to
fix some omitted formats and upgrade to latest pyparsing idioms,
beginning with writing an actual BNF.
- With the help and encouragement from several contributors, including
Matěj Cepl and Cengiz Kaygusuz, I've started cleaning up the internal
coding styles in core pyparsing, bringing it up to modern coding
practices from pyparsing's early development days dating back to
2003. Whitespace has been largely standardized along PEP8 guidelines,
removing extra spaces around parentheses, and adding them around
arithmetic operators and after colons and commas. I was going to hold
off on doing this work until after 2.4.1, but after cleaning up a
few trial classes, the difference was so significant that I continued
on to the rest of the core code base. This should facilitate future
work and submitted PRs, allowing them to focus on substantive code
changes, and not get sidetracked by whitespace issues.