syntaxtree.py 38.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
# syntaxtree.py - syntax tree classes for DHParser
#
# Copyright 2016  by Eckhart Arnold (arnold@badw.de)
#                 Bavarian Academy of Sciences an Humanities (badw.de)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.  See the License for the specific language governing
# permissions and limitations under the License.
17 18 19


"""
20 21
Module ``syntaxtree`` defines the ``Node``-class for syntax trees as well
as an abstract base class for parser-objects. The latter is defined
eckhart's avatar
eckhart committed
22
here, because node-objects refer to parser-objects. All concrete
23 24 25
parser classes are defined in the ``parse`` module.
"""

26

Eckhart Arnold's avatar
Eckhart Arnold committed
27
import collections.abc
28
from collections import OrderedDict
29

30
from DHParser.error import Error, linebreaks, line_col
31
from DHParser.stringview import StringView
eckhart's avatar
eckhart committed
32
from DHParser.toolkit import re, typing
eckhart's avatar
eckhart committed
33
from typing import Callable, cast, Iterator, List, AbstractSet, Set, Union, Tuple, Optional
di68kap's avatar
di68kap committed
34

35

36 37 38 39 40 41
__all__ = ('ParserBase',
           'WHITESPACE_PTYPE',
           'TOKEN_PTYPE',
           'MockParser',
           'ZombieParser',
           'ZOMBIE_PARSER',
eckhart's avatar
eckhart committed
42
           'ZOMBIE_NODE',
43
           'Node',
di68kap's avatar
di68kap committed
44
           'RootNode',
45
           'parse_sxpr',
46 47 48
           'parse_xml',
           'flatten_sxpr',
           'flatten_xml')
Eckhart Arnold's avatar
Eckhart Arnold committed
49 50


51 52 53 54 55 56 57 58 59 60 61 62 63
#######################################################################
#
# parser base and mock parsers
#
#######################################################################


class ParserBase:
    """
    ParserBase is the base class for all real and mock parser classes.
    It is defined here, because Node objects require a parser object
    for instantiation.
    """
64
    __slots__ = 'name', 'ptype'
Eckhart Arnold's avatar
Eckhart Arnold committed
65

66 67 68
    def __init__(self,):  # , pbases=frozenset()):
        self.name = ''  # type: str
        self.ptype = ':' + self.__class__.__name__  # type: str
69 70

    def __repr__(self):
di68kap's avatar
di68kap committed
71
         return self.name + self.ptype
72 73 74 75

    def __str__(self):
        return self.name + (' = ' if self.name else '') + repr(self)

76 77 78
    def __call__(self, text: StringView) -> Tuple[Optional['Node'], StringView]:
        return None, text

79 80 81 82 83 84 85 86 87 88 89
    # @property
    # def name(self):
    #     """Returns the name of the parser or the empty string '' for unnamed
    #     parsers."""
    #     return self._name
    #
    # @property
    # def ptype(self) -> str:
    #     """Returns the type of the parser. By default this is the parser's
    #     class name preceded by a colon, e.g. ':ZeroOrMore'."""
    #     return self._ptype
90 91 92

    @property
    def repr(self) -> str:
di68kap's avatar
di68kap committed
93
        """Returns the parser's name if it has a name and repr()"""
94 95
        return self.name if self.name else repr(self)

96
    def reset(self):
97
        """Resets any parser variables. (Should be overridden.)"""
98 99
        pass

eckhart's avatar
eckhart committed
100
    def grammar(self) -> Optional[object]:
101 102
        """Returns the Grammar object to which the parser belongs. If not
        yet connected to any Grammar object, None is returned."""
103 104 105
        return None

    def apply(self, func: Callable) -> bool:
eckhart's avatar
eckhart committed
106
        """Applies the function `func` to the parser. Returns False, if
107
        - for whatever reason - the functions has not been applied, True
eckhart's avatar
eckhart committed
108
        otherwise."""
109 110
        return False

111 112

WHITESPACE_PTYPE = ':Whitespace'
113
TOKEN_PTYPE = ':Token'
114 115 116 117 118 119


class MockParser(ParserBase):
    """
    MockParser objects can be used to reconstruct syntax trees from a
    serialized form like S-expressions or XML. Mock objects can mimic
eckhart's avatar
eckhart committed
120
    different parser types by assigning them a `ptype` on initialization.
121 122 123 124 125

    Mock objects should not be used for anything other than
    syntax tree (re-)construction. In all other cases where a parser
    object substitute is needed, chose the singleton ZOMBIE_PARSER.
    """
Eckhart Arnold's avatar
Eckhart Arnold committed
126 127
    __slots__ = ()

128 129
    def __init__(self, name='', ptype=''):  # , pbases=frozenset()):
        assert not ptype or ptype[0] == ':'
130 131
        super().__init__()
        self.name = name
di68kap's avatar
di68kap committed
132 133
        if ptype:
            self.ptype = ptype  # or ':' + self.__class__.__name__
134 135 136 137 138 139 140 141 142 143 144 145 146


class ZombieParser(MockParser):
    """
    Serves as a substitute for a Parser instance.

    ``ZombieParser`` is the class of the singelton object
    ``ZOMBIE_PARSER``. The  ``ZOMBIE_PARSER`` has a name and can be
    called, but it never matches. It serves as a substitute where only
    these (or one of these properties) is needed, but no real Parser-
    object is instantiated.
    """
    alive = False
Eckhart Arnold's avatar
Eckhart Arnold committed
147
    __slots__ = ()
148 149

    def __init__(self):
150
        super(ZombieParser, self).__init__()
151 152
        assert not self.__class__.alive, "There can be only one!"
        assert self.__class__ == ZombieParser, "No derivatives, please!"
153
        self.name = "__ZOMBIE__"
154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
        self.__class__.alive = True

    def __copy__(self):
        return self

    def __deepcopy__(self, memo):
        return self

    def __call__(self, text):
        """Better call Saul ;-)"""
        return None, text


ZOMBIE_PARSER = ZombieParser()


#######################################################################
#
# syntaxtree nodes
#
#######################################################################


177
ChildrenType = Tuple['Node', ...]
Eckhart Arnold's avatar
Eckhart Arnold committed
178
NoChildren = cast(ChildrenType, ())  # type: ChildrenType
eckhart's avatar
eckhart committed
179
StrictResultType = Union[ChildrenType, StringView, str]
180
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
181 182


Eckhart Arnold's avatar
Eckhart Arnold committed
183
def flatten_sxpr(sxpr: str) -> str:
184
    """Returns S-expression ``sxpr`` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
185 186 187
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
188
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
189 190
    '(a (b c))'
    """
191
    return re.sub(r'\s(?=\))', '', re.sub(r'\s+', ' ', sxpr)).strip()
Eckhart Arnold's avatar
Eckhart Arnold committed
192 193


194
def flatten_xml(xml: str) -> str:
195
    """Returns an XML-tree as a one liner without unnecessary whitespace,
196 197
    i.e. only whitespace within leaf-nodes is preserved.
    """
198 199 200 201 202
    # works only with regex
    # return re.sub(r'\s+(?=<\w)', '', re.sub(r'(?<=</\w+>)\s+', '', xml))
    def tag_only(m):
        return m.groupdict()['closing_tag']
    return re.sub(r'\s+(?=<\w)', '', re.sub(r'(?P<closing_tag></\w+>)\s+', tag_only, xml))
203 204


Eckhart Arnold's avatar
Eckhart Arnold committed
205
class Node(collections.abc.Sized):
206 207 208
    """
    Represents a node in the concrete or abstract syntax tree.

209
    Attributes:
210 211
        tag_name (str):  The name of the node, which is either its
            parser's name or, if that is empty, the parser's class name
212

213 214 215
        result (str or tuple):  The result of the parser which
            generated this node, which can be either a string or a
            tuple of child nodes.
216

217 218
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
219

eckhart's avatar
eckhart committed
220 221 222 223
        content (str):  Yields the contents of the tree as string. The
            difference to ``str(node)`` is that ``node.content`` does
            not add the error messages to the returned string.

Eckhart Arnold's avatar
Eckhart Arnold committed
224
        parser (Parser):  The parser which generated this node.
225 226
            WARNING: In case you use mock syntax trees for testing or
            parser replacement during the AST-transformation: DO NOT
Eckhart Arnold's avatar
Eckhart Arnold committed
227 228
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
229
            example by calling ``isinstance(node.parer, ...)``.
230

231 232 233
        len (int):  The full length of the node's string result if the
            node is a leaf node or, otherwise, the concatenated string
            result's of its descendants. The figure always represents
234
            the length before AST-transformation and will never change
235
            through AST-transformation. READ ONLY!
236

237 238
        pos (int):  the position of the node within the parsed text.

Eckhart Arnold's avatar
Eckhart Arnold committed
239
            The value of ``pos`` is -1 meaning invalid by default.
240
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
241
            nodes relative to this value.
242 243

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
244
            pos value of the root node should be set to 0 right
245 246
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
247
            Other than that, this value should be considered READ ONLY.
248 249
            At any rate, it should only be reassigned during the parsing
            stage and never during or after the AST-transformation.
250

251 252
        errors (list):  A list of all errors that occured on this node.

253 254
        attr (dict): An optional dictionary of XML-attr. This
            dictionary is created lazily upon first usage. The attr
255 256
            will only be shown in the XML-Representation, not in the
            S-Expression-output.
257
    """
258

Eckhart Arnold's avatar
Eckhart Arnold committed
259
    __slots__ = '_result', 'children', '_len', '_pos', 'parser', 'errors', '_xml_attr', '_content'
260

261 262 263
    def __init__(self, parser, result: ResultType, leafhint: bool = False) -> None:
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
264 265
        that generated the node and the parser's result.
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
266
        self.errors = []                # type: List[Error]
eckhart's avatar
eckhart committed
267
        self._pos = -1                  # type: int
268
        # Assignment to self.result initializes the attr _result, children and _len
di68kap's avatar
di68kap committed
269
        # The following if-clause is merely an optimization, i.e. a fast-path for leaf-Nodes
270
        if leafhint:
eckhart's avatar
eckhart committed
271
            self._result = result       # type: StrictResultType
eckhart's avatar
eckhart committed
272
            self._content = None        # type: Optional[str]
273
            self.children = NoChildren  # type: ChildrenType
274
            self._len = -1              # type: int  # lazy evaluation
275 276
        else:
            self.result = result
277 278
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
279

280
    def __str__(self):
281
        s = "".join(str(child) for child in self.children) if self.children else self.content
eckhart's avatar
eckhart committed
282
        if self.errors:
283
            return ' <<< Error on "%s" | %s >>> ' % \
eckhart's avatar
eckhart committed
284
                   (s, '; '.join(e.message for e in self.errors))
285
        return s
286

Eckhart Arnold's avatar
Eckhart Arnold committed
287

288 289 290 291 292 293
    def __repr__(self):
        mpargs = {'name': self.parser.name, 'ptype': self.parser.ptype}
        parg = "MockParser({name}, {ptype})".format(**mpargs)
        rarg = str(self) if not self.children else \
               "(" + ", ".join(repr(child) for child in self.children) + ")"
        return "Node(%s, %s)" % (parg, rarg)
294

Eckhart Arnold's avatar
Eckhart Arnold committed
295

296
    def __len__(self):
297
        if self._len < 0:
di68kap's avatar
di68kap committed
298
            self._len = sum(len(child) for child in self.children) \
299
                if self.children else len(self._result)
300 301 302 303 304 305 306 307
        return self._len


    def __bool__(self):
        # A node that is not None is always True, even if it's empty
        return True


308
    def __eq__(self, other):
309 310 311 312
        """
        Equality of nodes: Two nodes are considered as equal, if their tag
        name is the same and if their results are equal.
        """
313
        return self.tag_name == other.tag_name and self.result == other.result
314

Eckhart Arnold's avatar
Eckhart Arnold committed
315

316
    def __hash__(self):
317
        return hash(self.tag_name)
318

Eckhart Arnold's avatar
Eckhart Arnold committed
319

320 321 322
    def __getitem__(self, index_or_tagname: Union[int, str]) -> Union['Node', Iterator['Node']]:
        """
        Returns the child node with the given index if ``index_or_tagname`` is
323
        an integer or the first child node with the given tag name. Examples::
324

325
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
326 327
            >>> flatten_sxpr(tree[0].as_sxpr())
            '(b "X")'
328 329
            >>> flatten_sxpr(tree["X"].as_sxpr())
            '(X (c "d"))'
330 331 332 333

        Args:
            index_or_tagname(str): Either an index of a child node or a
                tag name.
334
        Returns:
335 336
            Node: All nodes which have a given tag name.
        """
337 338 339
        if self.children:
            if isinstance(index_or_tagname, int):
                return self.children[index_or_tagname]
340
            else:
341 342 343 344 345
                for child in self.children:
                    if child.tag_name == index_or_tagname:
                        return child
                raise KeyError(index_or_tagname)
        raise ValueError('Leave nodes have no children that can be indexed!')
346 347 348 349


    def __contains__(self, tag_name: str) -> bool:
        """
350
        Returns true if a child with the given tag name exists.
351
        Args:
352 353
            tag_name (str): tag_name which will be searched among to immediate
                descendants of this node.
354 355 356 357
        Returns:
            bool:  True, if at least one descendant node with the given tag
                name exists, False otherwise
        """
358 359 360 361 362
        # assert isinstance(tag_name, str)
        if self.children:
            for child in self.children:
                if child.tag_name == tag_name:
                    return True
363
            return False
364
        raise ValueError('Leave node cannot contain other nodes')
365
        # generator = self.select_by_tag(tag_name, False)
366 367 368 369 370
        # try:
        #     generator.__next__()
        #     return True
        # except StopIteration:
        #     return False
371 372


373 374 375 376 377 378 379 380 381 382 383 384 385 386
    def get(self, index_or_tagname: Union[int, str],
            surrogate: Union['Node', Iterator['Node']]) -> Union['Node', Iterator['Node']]:
        """Returns the child node with the given index if ``index_or_tagname``
        is an integer or the first child node with the given tag name. If no
        child with the given index or tag_name exists, the ``surrogate`` is
        returned instead. This mimics the behaviour of Python's dictionary's
        get-method.
        """
        try:
            return self[index_or_tagname]
        except KeyError:
            return surrogate


387
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
388
    def tag_name(self) -> str:
389 390 391 392 393 394
        """
        Returns the tage name of Node, i.e. the name for XML or
        S-expression representation. By default the tag name is the
        name of the node's parser or, if the node's parser is unnamed, the
        node's parser's `ptype`.
        """
395
        return self.parser.name or self.parser.ptype
396

Eckhart Arnold's avatar
Eckhart Arnold committed
397

398
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
399
    def result(self) -> StrictResultType:
400 401 402 403 404
        """
        Returns the result from the parser that created the node.
        Error messages are not included in the result. Use `self.content()`
        if the result plus any error messages is needed.
        """
405 406
        return self._result

407

408
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
409
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
410
        # # made obsolete by static type checking with mypy
411 412 413
        # assert ((isinstance(result, tuple) and all(isinstance(child, Node) for child in result))
        #         or isinstance(result, Node)
        #         or isinstance(result, str)), str(result)
Eckhart Arnold's avatar
Eckhart Arnold committed
414 415
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
416 417
        self._len = -1        # lazy evaluation
        self._content = None
418 419 420 421 422 423 424 425 426
        if isinstance(result, Node):
            self.children = (result,)
            self._result = self.children
        else:
            if isinstance(result, tuple):
                self.children = result
                self._result = result or ''
            else:
                self.children = NoChildren
427
                self._result = result
428

429 430

    @property
eckhart's avatar
eckhart committed
431
    def content(self) -> str:
432
        """
433
        Returns content as string, omitting error messages.
434
        """
435 436 437 438
        if self._content is None:
            if self.children:
                self._content = "".join(child.content for child in self.children)
            else:
439
                # self._content = self._result
440 441 442
                self._content = str(self._result)
                self._result = self._content  # self._result might be more efficient as a string!?
        return self._content
443 444 445 446 447 448 449 450 451 452 453


    @property
    def structure(self) -> str:
        """
        Return structure (and content) as S-expression on a single line
        without any line breaks.
        """
        return flatten_sxpr(self.as_sxpr(showerrors=False))


454
    @property
455
    def pos(self) -> int:
eckhart's avatar
eckhart committed
456 457
        """Returns the position of the Node's content in the source text."""
        if self._pos < 0:
458
            raise AssertionError("Position value not initialized!")
459 460
        return self._pos

eckhart's avatar
eckhart committed
461

eckhart's avatar
eckhart committed
462
    def init_pos(self, pos: int) -> 'Node':
eckhart's avatar
eckhart committed
463 464 465 466 467 468 469 470 471
        """
        (Re-)initialize position value. Usually, the parser guard
        (`parsers.add_parser_guard()`) takes care of assigning the
        position in the document to newly created nodes. However,
        where Nodes are created outside the reach of the parser
        guard, their document-position must be assigned manually.
        This function recursively reassigns the position values
        of the child nodes, too.
        """
eckhart's avatar
eckhart committed
472 473
        assert self._pos < 0 or self.pos == pos, str("pos mismatch %i != %i" % (self._pos, pos))
        self._pos = pos
474
        # recursively adjust pos-values of all children
eckhart's avatar
eckhart committed
475
        offset = self.pos
476
        for child in self.children:
eckhart's avatar
eckhart committed
477
            child.init_pos(offset)
eckhart's avatar
eckhart committed
478 479 480
            offset = child.pos + len(child)
        return self

481

482
    @property
483
    def attr(self):
484
        """
485
        Returns a dictionary of XML-attr attached to the node.
486
        """
487 488 489 490
        if not hasattr(self, '_xml_attr'):
            self._xml_attr = OrderedDict()
        return self._xml_attr

Eckhart Arnold's avatar
Eckhart Arnold committed
491

492
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=lambda i: i,
493
                   density=0, inline=False, inline_fn=lambda node: False) -> str:
494 495 496 497 498 499 500 501
        """
        Generates a tree representation of this node and its children
        in string from.

        The kind ot tree-representation that is determined by several
        function parameters. This could be an XML-representation or a
        lisp-like S-expression.

502
        Args:
503
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
504
            open_fn:   (Node->str) A function that returns an opening
505
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
506
            close_fn:  (Node->str) A function that returns a closeF
507
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
508
            data_fn:   (str->str) A function that filters the data string
509 510 511 512 513 514
                before printing, e.g. to add quotation marks

        Returns (str):
            A string that contains a (serialized) tree representation
            of the node and its children.
        """
eckhart's avatar
eckhart committed
515 516
        head = open_fn(self)
        tail = close_fn(self)
517 518

        if not self.result:
519
            return head.rstrip() + tail.lstrip()
520

eckhart's avatar
eckhart committed
521
        tail = tail.lstrip(None if density & 2 else '')
522

523
        inline = inline or inline_fn(self)
524 525 526 527 528
        if inline:
            head = head.rstrip()
            tail = tail.lstrip()
            usetab, sep = '', ''
        else:
eckhart's avatar
eckhart committed
529 530
            usetab = tab if head else ''    # no indentation if tag is already omitted
            sep = '\n'
531

532 533
        if self.children:
            content = []
534
            for child in self.children:
535
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn,
536
                                           density, inline, inline_fn)
eckhart's avatar
eckhart committed
537 538 539
                if subtree:
                    subtree = [subtree] if inline else subtree.split('\n')
                    content.append((sep + usetab).join(s for s in subtree))
540
            return head + usetab + (sep + usetab).join(content) + tail
541

542
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
eckhart's avatar
eckhart committed
543
        if not inline and not head:
eckhart's avatar
eckhart committed
544
            # strip whitespace for omitted non inline node, e.g. CharData in mixed elements
eckhart's avatar
eckhart committed
545
            res = res.strip()
546 547
        if density & 1 and res.find('\n') < 0:  # and head[0] == "<":
            # except for XML, add a gap between opening statement and content
548
            gap = ' ' if not inline and head and head.rstrip()[-1:] != '>' else ''
eckhart's avatar
eckhart committed
549
            return head.rstrip() + gap + data_fn(res) + tail.lstrip()
550
        else:
551
            return head + '\n'.join([usetab + data_fn(s) for s in res.split('\n')]) + tail
552

Eckhart Arnold's avatar
Eckhart Arnold committed
553

554 555 556
    def as_sxpr(self, src: str = None,
                showerrors: bool = True,
                indentation: int = 2,
557
                compact: bool = False) -> str:
558 559 560
        """
        Returns content as S-expression, i.e. in lisp-like form.

561
        Args:
562 563 564
            src:  The source text or `None`. In case the source text is
                given the position of the element in the text will be
                reported as line and column.
565 566 567
            showerrors: If True, error messages will be shown.
            indentation: The number of whitespaces for indentation
            compact:  If True, a compact representation is returned where
568
                brackets are omitted and only the indentation indicates the
Eckhart Arnold's avatar
Eckhart Arnold committed
569
                tree structure.
570 571
        """

eckhart's avatar
eckhart committed
572
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
eckhart's avatar
eckhart committed
573
        lbreaks = linebreaks(src) if src else []  # type: List[int]
574

575
        def opening(node) -> str:
eckhart's avatar
eckhart committed
576
            """Returns the opening string for the representation of `node`."""
577
            txt = [left_bracket,  node.tag_name]
578
            # s += " '(pos %i)" % node.add_pos
579
            if hasattr(node, '_xml_attr'):
580
                txt.extend(' `(%s "%s")' % (k, v) for k, v in node.attr.items())
581
            if src:
eckhart's avatar
eckhart committed
582
                txt.append(" `(pos %i %i %i)" % (node.pos, *line_col(lbreaks, node.pos)))
583
            if showerrors and node.errors:
584
                txt.append(" `(err `%s)" % ' '.join(str(err) for err in node.errors))
585
            return "".join(txt) + '\n'
586

eckhart's avatar
eckhart committed
587 588 589
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
590

eckhart's avatar
eckhart committed
591 592 593 594 595
        def pretty(strg):
            """Encloses `strg` with the right kind of quotation marks."""
            return '"%s"' % strg if strg.find('"') < 0 \
                else "'%s'" % strg if strg.find("'") < 0 \
                else '"%s"' % strg.replace('"', r'\"')
596

597
        return self._tree_repr(' ' * indentation, opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
598

eckhart's avatar
eckhart committed
599

600 601 602 603 604 605
    def as_xml(self, src: str = None,
               showerrors: bool = True,
               indentation: int = 2,
               inline_tags: Set[str]=set(),
               omit_tags: Set[str]=set(),
               empty_tags: Set[str]=set()) -> str:
606 607 608
        """
        Returns content as XML-tree.

609
        Args:
610 611 612
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
613 614
            showerrors: If True, error messages will be shown.
            indentation: The number of whitespaces for indentation
615 616 617
            inline_tags:  A set of tag names, the content of which will always be written
                on a single line, unless it contains explicit line feeds ('\n').
            omit_tags:  A set of tags from which only the content will be printed, but
618
                neither the opening tag nor its attr nor the closing tag. This
619 620 621
                allows producing a mix of plain text and child tags in the output,
                which otherwise is not supported by the Node object, because it
                requires its content to be either a tuple of children or string content.
622 623
            empty_tags:  A set of tags which shall be rendered as empty elements, e.g.
                "<empty/>" instead of "<empty><empty>".
624 625
        """

626
        def opening(node) -> str:
627 628 629
            """Returns the opening string for the representation of `node`."""
            if node.tag_name in omit_tags:
                return ''
eckhart's avatar
eckhart committed
630
            txt = ['<', node.tag_name]
631
            has_reserved_attrs = hasattr(node, '_xml_attr') \
632
                and any (r in node.attr for r in {'err', 'line', 'col'})
di68kap's avatar
di68kap committed
633
            if hasattr(node, '_xml_attr'):
634
                txt.extend(' %s="%s"' % (k, v) for k, v in node.attr.items())
635
            if src and not has_reserved_attrs:
eckhart's avatar
eckhart committed
636
                txt.append(' line="%i" col="%i"' % line_col(line_breaks, node.pos))
637
            if showerrors and node.errors and not has_reserved_attrs:
eckhart's avatar
eckhart committed
638 639
                txt.append(' err="%s"' % ''.join(str(err).replace('"', r'\"')
                                                 for err in node.errors))
640 641 642
            if node.tag_name in empty_tags:
                assert not node.result, ("Node %s with content %s is not an empty element!" %
                                         (node.tag_name, str(node)))
eckhart's avatar
eckhart committed
643
                ending = "/>\n" if not node.tag_name[0] == '?' else "?>\n"
644 645 646
            else:
                ending = ">\n"
            return "".join(txt + [ending])
647 648

        def closing(node):
649
            """Returns the closing string for the representation of `node`."""
650
            if node.tag_name in omit_tags or node.tag_name in empty_tags:
651
                return ''
652
            return ('\n</') + node.tag_name + '>'
653

654 655 656 657 658
        def inlining(node):
            """Returns True, if `node`'s tag name is contained in `inline_tags`,
            thereby signalling that the children of this node shall not be
            printed on several lines to avoid unwanted gaps in the output.
            """
659
            return node.tag_name in inline_tags or (hasattr(node, '_xml_attr') \
660
                                                    and node.attr.get('xml:space', 'default') == 'preserve')
661

662
        line_breaks = linebreaks(src) if src else []
663 664
        return self._tree_repr(' ' * indentation, opening, closing,
                               density=1, inline_fn=inlining)
665

Eckhart Arnold's avatar
Eckhart Arnold committed
666

667
    def select(self, match_function: Callable, include_root: bool=False) -> Iterator['Node']:
eckhart's avatar
eckhart committed
668
        """
669
        Finds nodes in the tree that fulfill a given criterion.
eckhart's avatar
eckhart committed
670

671
        `select` is a generator that yields all nodes for which the
di68kap's avatar
di68kap committed
672
        given `match_function` evaluates to True. The tree is
673 674 675
        traversed pre-order.

        See function `Node.select_by_tag` for some examples.
eckhart's avatar
eckhart committed
676

677 678 679
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
680 681
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
682
        Yields:
683
            Node: All nodes of the tree for which
684 685
            ``match_function(node)`` returns True
        """
686
        if include_root and match_function(self):
687
            yield self
eckhart's avatar
eckhart committed
688 689 690
        for child in self.children:
            for node in child.select(match_function, True):
                yield node
691

Eckhart Arnold's avatar
Eckhart Arnold committed
692

eckhart's avatar
eckhart committed
693
    def select_by_tag(self, tag_names: Union[str, AbstractSet[str]],
694
                      include_root: bool=False) -> Iterator['Node']:
695
        """
696 697 698 699
        Returns an iterator that runs through all descendants that have one
        of the given tag names.

        Examples::
700

701
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
702
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag("X", False))
703
            ['(X (c "d"))', '(X "F")']
704
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag({"X", "b"}, False))
705
            ['(b "X")', '(X (c "d"))', '(X "F")']
706
            >>> any(tree.select_by_tag('a', False))
707
            False
708
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag('a', True))
709
            ['(a (b "X") (X (c "d")) (e (X "F")))']
710 711
            >>> flatten_sxpr(next(tree.select_by_tag("X", False)).as_sxpr())
            '(X (c "d"))'
712 713

        Args:
714 715 716 717
            tag_name(set): A tag name or set of tag names that is being
                searched for
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
718 719 720
        Yields:
            Node: All nodes which have a given tag name.
        """
721
        if isinstance(tag_names, str):
eckhart's avatar
eckhart committed
722
            tag_names = frozenset({tag_names})
723
        return self.select(lambda node: node.tag_name in tag_names, include_root)
724 725


726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
    def pick(self, tag_names: Union[str, Set[str]]) -> Optional['Node']:
        """
        Picks the first descendant with one of the given tag_names.

        This function is just syntactic sugar for
        ``next(node.select_by_tag(tag_names, False))``. However, rather than
        raising a StopIterationError if no descendant with the given tag-name
        exists, it returns None.
        """
        try:
            return next(self.select_by_tag(tag_names, False))
        except StopIteration:
            return None


741
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
742 743 744
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
745 746 747
        return sum(child.tree_size() for child in self.children) + 1


di68kap's avatar
di68kap committed
748
class RootNode(Node):
749
    """TODO: Add Documentation!!!
di68kap's avatar
di68kap committed
750

Eckhart Arnold's avatar
Eckhart Arnold committed
751
        all_errors (list):  A list of all errors that have occured so far during
752 753
                processing (i.e. parsing, AST-transformation, compiling)
                of this tree.
di68kap's avatar
di68kap committed
754

755 756
        error_flag (int):  the highest warning or error level of all errors
                that occurred.
di68kap's avatar
di68kap committed
757
    """
eckhart's avatar
eckhart committed
758
    def __init__(self, node: Optional[Node] = None) -> 'RootNode':
di68kap's avatar
di68kap committed
759
        super().__init__(ZOMBIE_PARSER, '')
760
        self.all_errors = []
di68kap's avatar
di68kap committed
761
        self.error_flag = 0
eckhart's avatar
eckhart committed
762 763
        if node is not None:
            self.swallow(node)
764 765 766 767
        # customization for XML-Representation
        self.inline_tags = set()
        self.omit_tags = set()
        self.empty_tags = set()
di68kap's avatar
di68kap committed
768

769
    def swallow(self, node: Node) -> 'RootNode':
770 771 772 773 774 775 776 777 778 779
        """Put `self` in the place of `node` by copying all its data.
        Returns self.

        This is done by the parse.Grammar object after
        parsing has finished, so that the Grammar object always
        returns a syntax tree rooted in a RootNode object.

        It is possible to add errors to a RootNode object, before it
        has actually swallowed the root of the syntax tree.
        """
di68kap's avatar
di68kap committed
780 781 782 783 784
        self._result = node._result
        self.children = node.children
        self._len = node._len
        self._pos = node._pos
        self.parser = node.parser
785 786
        if hasattr(node, '_xml_attr'):
            self._xml_attr = node._xml_attr
di68kap's avatar
di68kap committed
787
        self._content = node._content
788
        return self
di68kap's avatar
di68kap committed
789

eckhart's avatar
eckhart committed
790 791
    def add_error(self, node: Node, error: Error) -> 'RootNode':
        """Adds an Error object to the tree, locating it at a specific node."""
di68kap's avatar
di68kap committed
792 793 794 795 796
        self.all_errors.append(error)
        self.error_flag = max(self.error_flag, error.code)
        node.errors.append(error)
        return self

eckhart's avatar
eckhart committed
797
    def new_error(self,
798
                  node: Node,
di68kap's avatar
di68kap committed
799
                  message: str,
di68kap's avatar
di68kap committed
800
                  code: int = Error.ERROR) -> 'RootNode':
di68kap's avatar
di68kap committed
801
        """
eckhart's avatar
eckhart committed
802
        Adds an error to this tree, locating it at a specific node.
di68kap's avatar
di68kap committed
803 804 805 806 807
        Parameters:
            pos(int):     The position of the error in the source text
            message(str): A string with the error message.abs
            code(int):    An error code to identify the kind of error
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
808
        error = Error(message, node.pos, code)
eckhart's avatar
eckhart committed
809 810
        self.add_error(node, error)
        return self
di68kap's avatar
di68kap committed
811

eckhart's avatar
eckhart committed
812
    def collect_errors(self) -> List[Error]:
di68kap's avatar
di68kap committed
813 814
        """Returns the list of errors, ordered bv their position.
        """
815
        self.all_errors.sort(key=lambda e: e.pos)
Eckhart Arnold's avatar
Eckhart Arnold committed
816
        return self.all_errors
di68kap's avatar
di68kap committed
817

818 819 820 821 822 823 824 825
    def customized_XML(self):
        """Returns a customized XML representation of the tree.
        See the docstring of `Node.as_xml()` for an explanation of the
        customizations."""
        return self.as_xml(inline_tags = self.inline_tags,
                           omit_tags=self.omit_tags,
                           empty_tags=self.empty_tags)

di68kap's avatar
di68kap committed
826

eckhart's avatar
eckhart committed
827 828 829
ZOMBIE_NODE = Node(ZOMBIE_PARSER, '')


830
def parse_sxpr(sxpr: str) -> Node:
831
    """
832 833 834 835 836
    Generates a tree of nodes from an S-expression.

    This can - among other things - be used for deserialization of trees that
    have been serialized with `Node.as_sxpr()` or as a convenient way to
    generate test data.
837 838

    Example:
839
    >>> parse_sxpr("(a (b c))").as_sxpr()
840
    '(a\\n  (b\\n    "c"\\n  )\\n)'
841
    """
842 843
    sxpr = StringView(sxpr).strip()
    mock_parsers = dict()
844

845
    def next_block(s: StringView):
eckhart's avatar
eckhart committed
846 847 848
        """Generator that yields all characters until the next closing bracket
        that does not match an opening bracket matched earlier within the same
        package."""
849
        s = s.strip()
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868
        try:
            while s[0] != ')':
                if s[0] != '(':
                    raise ValueError('"(" expected, not ' + s[:10])
                # assert s[0] == '(', s
                level = 1
                k = 1
                while level > 0:
                    if s[k] == '(':
                        level += 1
                    elif s[k] == ')':
                        level -= 1
                    k += 1
                yield s[:k]
                s = s[k:].strip()
        except IndexError:
            errmsg = ('Malformed S-expression. Unprocessed part: "%s"' % s) if s \
                else 'Malformed S-expression. Closing bracket(s) ")" missing.'
            raise AssertionError(errmsg)
869

870 871 872