diff options
Diffstat (limited to 'src/pip/_vendor/pyparsing/actions.py')
| -rw-r--r-- | src/pip/_vendor/pyparsing/actions.py | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/src/pip/_vendor/pyparsing/actions.py b/src/pip/_vendor/pyparsing/actions.py new file mode 100644 index 000000000..f72c66e74 --- /dev/null +++ b/src/pip/_vendor/pyparsing/actions.py @@ -0,0 +1,207 @@ +# actions.py + +from .exceptions import ParseException +from .util import col + + +class OnlyOnce: + """ + Wrapper for parse actions, to ensure they are only called once. + """ + + def __init__(self, method_call): + from .core import _trim_arity + + self.callable = _trim_arity(method_call) + self.called = False + + def __call__(self, s, l, t): + if not self.called: + results = self.callable(s, l, t) + self.called = True + return results + raise ParseException(s, l, "OnlyOnce obj called multiple times w/out reset") + + def reset(self): + """ + Allow the associated parse action to be called once more. + """ + + self.called = False + + +def match_only_at_col(n): + """ + Helper method for defining parse actions that require matching at + a specific column in the input text. + """ + + def verify_col(strg, locn, toks): + if col(locn, strg) != n: + raise ParseException(strg, locn, "matched token not at column {}".format(n)) + + return verify_col + + +def replace_with(repl_str): + """ + Helper method for common parse actions that simply return + a literal value. Especially useful when used with + :class:`transform_string<ParserElement.transform_string>` (). + + Example:: + + num = Word(nums).set_parse_action(lambda toks: int(toks[0])) + na = one_of("N/A NA").set_parse_action(replace_with(math.nan)) + term = na | num + + term[1, ...].parse_string("324 234 N/A 234") # -> [324, 234, nan, 234] + """ + return lambda s, l, t: [repl_str] + + +def remove_quotes(s, l, t): + """ + Helper parse action for removing quotation marks from parsed + quoted strings. + + Example:: + + # by default, quotation marks are included in parsed results + quoted_string.parse_string("'Now is the Winter of our Discontent'") # -> ["'Now is the Winter of our Discontent'"] + + # use remove_quotes to strip quotation marks from parsed results + quoted_string.set_parse_action(remove_quotes) + quoted_string.parse_string("'Now is the Winter of our Discontent'") # -> ["Now is the Winter of our Discontent"] + """ + return t[0][1:-1] + + +def with_attribute(*args, **attr_dict): + """ + Helper to create a validating parse action to be used with start + tags created with :class:`make_xml_tags` or + :class:`make_html_tags`. Use ``with_attribute`` to qualify + a starting tag with a required attribute value, to avoid false + matches on common tags such as ``<TD>`` or ``<DIV>``. + + Call ``with_attribute`` with a series of attribute names and + values. Specify the list of filter attributes names and values as: + + - keyword arguments, as in ``(align="right")``, or + - as an explicit dict with ``**`` operator, when an attribute + name is also a Python reserved word, as in ``**{"class":"Customer", "align":"right"}`` + - a list of name-value tuples, as in ``(("ns1:class", "Customer"), ("ns2:align", "right"))`` + + For attribute names with a namespace prefix, you must use the second + form. Attribute names are matched insensitive to upper/lower case. + + If just testing for ``class`` (with or without a namespace), use + :class:`with_class`. + + To verify that the attribute exists, but without specifying a value, + pass ``with_attribute.ANY_VALUE`` as the value. + + Example:: + + html = ''' + <div> + Some text + <div type="grid">1 4 0 1 0</div> + <div type="graph">1,3 2,3 1,1</div> + <div>this has no type</div> + </div> + + ''' + div,div_end = make_html_tags("div") + + # only match div tag having a type attribute with value "grid" + div_grid = div().set_parse_action(with_attribute(type="grid")) + grid_expr = div_grid + SkipTo(div | div_end)("body") + for grid_header in grid_expr.search_string(html): + print(grid_header.body) + + # construct a match with any div tag having a type attribute, regardless of the value + div_any_type = div().set_parse_action(with_attribute(type=with_attribute.ANY_VALUE)) + div_expr = div_any_type + SkipTo(div | div_end)("body") + for div_header in div_expr.search_string(html): + print(div_header.body) + + prints:: + + 1 4 0 1 0 + + 1 4 0 1 0 + 1,3 2,3 1,1 + """ + if args: + attrs = args[:] + else: + attrs = attr_dict.items() + attrs = [(k, v) for k, v in attrs] + + def pa(s, l, tokens): + for attrName, attrValue in attrs: + if attrName not in tokens: + raise ParseException(s, l, "no matching attribute " + attrName) + if attrValue != with_attribute.ANY_VALUE and tokens[attrName] != attrValue: + raise ParseException( + s, + l, + "attribute {!r} has value {!r}, must be {!r}".format( + attrName, tokens[attrName], attrValue + ), + ) + + return pa + + +with_attribute.ANY_VALUE = object() + + +def with_class(classname, namespace=""): + """ + Simplified version of :class:`with_attribute` when + matching on a div class - made difficult because ``class`` is + a reserved word in Python. + + Example:: + + html = ''' + <div> + Some text + <div class="grid">1 4 0 1 0</div> + <div class="graph">1,3 2,3 1,1</div> + <div>this <div> has no class</div> + </div> + + ''' + div,div_end = make_html_tags("div") + div_grid = div().set_parse_action(with_class("grid")) + + grid_expr = div_grid + SkipTo(div | div_end)("body") + for grid_header in grid_expr.search_string(html): + print(grid_header.body) + + div_any_type = div().set_parse_action(with_class(withAttribute.ANY_VALUE)) + div_expr = div_any_type + SkipTo(div | div_end)("body") + for div_header in div_expr.search_string(html): + print(div_header.body) + + prints:: + + 1 4 0 1 0 + + 1 4 0 1 0 + 1,3 2,3 1,1 + """ + classattr = "{}:class".format(namespace) if namespace else "class" + return with_attribute(**{classattr: classname}) + + +# pre-PEP8 compatibility symbols +replaceWith = replace_with +removeQuotes = remove_quotes +withAttribute = with_attribute +withClass = with_class +matchOnlyAtCol = match_only_at_col |