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| # 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 | |
| OneOrMore(term).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 | |