10.12., 9:00 - 11:00: Due to updates GitLab may be unavailable for some minutes between 09:00 and 11:00.

syntaxtree.py 35.8 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
import copy
30

31
from DHParser.error import Error, linebreaks, line_col
32
from DHParser.stringview import StringView
eckhart's avatar
eckhart committed
33
from DHParser.toolkit import re, typing
eckhart's avatar
eckhart committed
34
from typing import Callable, cast, Iterator, List, AbstractSet, Set, Union, Tuple, Optional
di68kap's avatar
di68kap committed
35

36

37 38 39 40 41 42
__all__ = ('ParserBase',
           'WHITESPACE_PTYPE',
           'TOKEN_PTYPE',
           'MockParser',
           'ZombieParser',
           'ZOMBIE_PARSER',
eckhart's avatar
eckhart committed
43
           'ZOMBIE_NODE',
44
           'Node',
di68kap's avatar
di68kap committed
45
           'RootNode',
46
           'parse_sxpr',
47 48 49
           'parse_xml',
           'flatten_sxpr',
           'flatten_xml')
Eckhart Arnold's avatar
Eckhart Arnold committed
50 51


52 53 54 55 56 57 58 59 60 61 62 63 64 65
#######################################################################
#
# 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.
    """
    def __init__(self, name=''):  # , pbases=frozenset()):
66
        self._name = name  # type: str
67 68 69
        self._ptype = ':' + self.__class__.__name__  # type: str

    def __repr__(self):
di68kap's avatar
di68kap committed
70
         return self.name + self.ptype
71 72 73 74

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

75 76 77
    def __call__(self, text: StringView) -> Tuple[Optional['Node'], StringView]:
        return None, text

78 79
    @property
    def name(self):
80 81
        """Returns the name of the parser or the empty string '' for unnamed
        parsers."""
82 83
        return self._name

84 85
    @property
    def ptype(self) -> str:
86 87
        """Returns the type of the parser. By default this is the parser's
        class name preceded by a colon, e.g. ':ZeroOrMore'."""
88 89 90 91
        return self._ptype

    @property
    def repr(self) -> str:
di68kap's avatar
di68kap committed
92
        """Returns the parser's name if it has a name and repr()"""
93 94
        return self.name if self.name else repr(self)

95
    def reset(self):
96
        """Resets any parser variables. (Should be overridden.)"""
97 98
        pass

eckhart's avatar
eckhart committed
99
    def grammar(self) -> Optional[object]:
100 101
        """Returns the Grammar object to which the parser belongs. If not
        yet connected to any Grammar object, None is returned."""
102 103 104
        return None

    def apply(self, func: Callable) -> bool:
eckhart's avatar
eckhart committed
105
        """Applies the function `func` to the parser. Returns False, if
106
        - for whatever reason - the functions has not been applied, True
eckhart's avatar
eckhart committed
107
        otherwise."""
108 109
        return False

110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126

WHITESPACE_PTYPE = ':Whitespace'
TOKEN_PTYPE = ':Token'


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
    different parser types by assigning them a ptype on initialization.

    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.
    """
    def __init__(self, name='', ptype=''):  # , pbases=frozenset()):
        assert not ptype or ptype[0] == ':'
127
        super().__init__(name)
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169
        self._ptype = ptype or ':' + self.__class__.__name__


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

    def __init__(self):
        super(ZombieParser, self).__init__("__ZOMBIE__")
        assert not self.__class__.alive, "There can be only one!"
        assert self.__class__ == ZombieParser, "No derivatives, please!"
        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
#
#######################################################################


170
ChildrenType = Tuple['Node', ...]
Eckhart Arnold's avatar
Eckhart Arnold committed
171
NoChildren = cast(ChildrenType, ())  # type: ChildrenType
eckhart's avatar
eckhart committed
172
StrictResultType = Union[ChildrenType, StringView, str]
173
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
174 175


Eckhart Arnold's avatar
Eckhart Arnold committed
176
def flatten_sxpr(sxpr: str) -> str:
177
    """Returns S-expression ``sxpr`` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
178 179 180
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
181
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
182 183
    '(a (b c))'
    """
184
    return re.sub(r'\s(?=\))', '', re.sub(r'\s+', ' ', sxpr)).strip()
Eckhart Arnold's avatar
Eckhart Arnold committed
185 186


187 188 189 190 191 192 193
def flatten_xml(xml: str) -> str:
    """Returns an XML-tree as a one linter without unnecessary whitespace,
    i.e. only whitespace within leaf-nodes is preserved.
    """
    return re.sub(r'\s+(?=<\w)', '', re.sub(r'(?<=</\w+>)\s+', '', xml))


Eckhart Arnold's avatar
Eckhart Arnold committed
194
class Node(collections.abc.Sized):
195 196 197
    """
    Represents a node in the concrete or abstract syntax tree.

198
    Attributes:
199 200
        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
201

202 203 204
        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.
205

206 207
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
208

eckhart's avatar
eckhart committed
209 210 211 212
        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
213
        parser (Parser):  The parser which generated this node.
214 215
            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
216 217
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
218
            example by calling ``isinstance(node.parer, ...)``.
219

220 221 222
        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
223
            the length before AST-transformation and will never change
224
            through AST-transformation. READ ONLY!
225

226 227
        pos (int):  the position of the node within the parsed text.

Eckhart Arnold's avatar
Eckhart Arnold committed
228
            The value of ``pos`` is -1 meaning invalid by default.
229
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
230
            nodes relative to this value.
231 232

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
233
            pos value of the root node should be set to 0 right
234 235
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
236
            Other than that, this value should be considered READ ONLY.
237 238
            At any rate, it should only be reassigned during the parsing
            stage and never during or after the AST-transformation.
239

240 241
        errors (list):  A list of all errors that occured on this node.

242
        attributes (dict): An optional dictionary of XML-attributes. This
243 244 245
            dictionary is created lazily upon first usage. The attributes
            will only be shown in the XML-Representation, not in the
            S-Expression-output.
246
    """
247

eckhart's avatar
eckhart committed
248
    __slots__ = ['_result', 'children', '_len', '_pos', 'parser', 'errors', '_xml_attr', '_content']
249

250 251 252
    def __init__(self, parser, result: ResultType, leafhint: bool = False) -> None:
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
253 254
        that generated the node and the parser's result.
        """
eckhart's avatar
eckhart committed
255
        self.errors = []               # type: List[Error]
eckhart's avatar
eckhart committed
256
        self._pos = -1                  # type: int
di68kap's avatar
di68kap committed
257 258
        # Assignment to self.result initializes the attributes _result, children and _len
        # The following if-clause is merely an optimization, i.e. a fast-path for leaf-Nodes
259
        if leafhint:
eckhart's avatar
eckhart committed
260
            self._result = result       # type: StrictResultType
eckhart's avatar
eckhart committed
261
            self._content = None        # type: Optional[str]
262
            self.children = NoChildren  # type: ChildrenType
263
            self._len = -1              # type: int  # lazy evaluation
264 265
        else:
            self.result = result
266 267
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
268

269
    def __str__(self):
270
        s = "".join(str(child) for child in self.children) if self.children else self.content
eckhart's avatar
eckhart committed
271
        if self.errors:
272
            return ' <<< Error on "%s" | %s >>> ' % \
eckhart's avatar
eckhart committed
273
                   (s, '; '.join(e.message for e in self.errors))
274
        return s
275

Eckhart Arnold's avatar
Eckhart Arnold committed
276

277 278 279 280 281 282
    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)
283

Eckhart Arnold's avatar
Eckhart Arnold committed
284

285
    def __len__(self):
286
        if self._len < 0:
di68kap's avatar
di68kap committed
287
            self._len = sum(len(child) for child in self.children) \
288
                if self.children else len(self._result)
289 290 291 292 293 294 295 296
        return self._len


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


297
    def __eq__(self, other):
298 299 300 301
        """
        Equality of nodes: Two nodes are considered as equal, if their tag
        name is the same and if their results are equal.
        """
302
        return self.tag_name == other.tag_name and self.result == other.result
303

Eckhart Arnold's avatar
Eckhart Arnold committed
304

305
    def __hash__(self):
306
        return hash(self.tag_name)
307

Eckhart Arnold's avatar
Eckhart Arnold committed
308

309 310 311 312 313 314
    def __deepcopy__(self, memodict={}):
        result = copy.deepcopy(self.result)
        other = Node(self.parser, result)
        other._pos = self._pos
        return other

Eckhart Arnold's avatar
Eckhart Arnold committed
315

316 317 318
    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
319
        an integer or the first child node with the given tag name. Examples::
320

321
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
322 323
            >>> flatten_sxpr(tree[0].as_sxpr())
            '(b "X")'
324 325
            >>> flatten_sxpr(tree["X"].as_sxpr())
            '(X (c "d"))'
326 327 328 329

        Args:
            index_or_tagname(str): Either an index of a child node or a
                tag name.
330
        Returns:
331 332
            Node: All nodes which have a given tag name.
        """
333 334 335
        if self.children:
            if isinstance(index_or_tagname, int):
                return self.children[index_or_tagname]
336
            else:
337 338 339 340 341
                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!')
342 343 344 345


    def __contains__(self, tag_name: str) -> bool:
        """
346
        Returns true if a child with the given tag name exists.
347
        Args:
348 349
            tag_name (str): tag_name which will be searched among to immediate
                descendants of this node.
350 351 352 353
        Returns:
            bool:  True, if at least one descendant node with the given tag
                name exists, False otherwise
        """
354 355 356 357 358
        # assert isinstance(tag_name, str)
        if self.children:
            for child in self.children:
                if child.tag_name == tag_name:
                    return True
359
            return False
360
        raise ValueError('Leave node cannot contain other nodes')
361
        # generator = self.select_by_tag(tag_name, False)
362 363 364 365 366
        # try:
        #     generator.__next__()
        #     return True
        # except StopIteration:
        #     return False
367 368


369
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
370
    def tag_name(self) -> str:
371 372 373 374 375 376
        """
        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`.
        """
377
        return self.parser.name or self.parser.ptype
378

Eckhart Arnold's avatar
Eckhart Arnold committed
379

380
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
381
    def result(self) -> StrictResultType:
382 383 384 385 386
        """
        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.
        """
387 388
        return self._result

389

390
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
391
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
392
        # # made obsolete by static type checking with mypy
393 394 395
        # 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
396 397
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
398 399
        self._len = -1        # lazy evaluation
        self._content = None
400 401 402 403 404 405 406 407 408
        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
409
                self._result = result
410

411 412

    @property
eckhart's avatar
eckhart committed
413
    def content(self) -> str:
414
        """
415
        Returns content as string, omitting error messages.
416
        """
417 418 419 420
        if self._content is None:
            if self.children:
                self._content = "".join(child.content for child in self.children)
            else:
421
                # self._content = self._result
422 423 424
                self._content = str(self._result)
                self._result = self._content  # self._result might be more efficient as a string!?
        return self._content
425 426 427 428 429 430 431 432 433 434 435


    @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))


436
    @property
437
    def pos(self) -> int:
eckhart's avatar
eckhart committed
438 439
        """Returns the position of the Node's content in the source text."""
        if self._pos < 0:
440
            raise AssertionError("Position value not initialized!")
441 442
        return self._pos

eckhart's avatar
eckhart committed
443

eckhart's avatar
eckhart committed
444
    def init_pos(self, pos: int) -> 'Node':
eckhart's avatar
eckhart committed
445 446 447 448 449 450 451 452 453
        """
        (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
454 455
        assert self._pos < 0 or self.pos == pos, str("pos mismatch %i != %i" % (self._pos, pos))
        self._pos = pos
456
        # recursively adjust pos-values of all children
eckhart's avatar
eckhart committed
457
        offset = self.pos
458
        for child in self.children:
eckhart's avatar
eckhart committed
459
            child.init_pos(offset)
eckhart's avatar
eckhart committed
460 461 462
            offset = child.pos + len(child)
        return self

463

464 465
    @property
    def attributes(self):
466 467 468
        """
        Returns a dictionary of XML-Attributes attached to the Node.
        """
469 470 471 472
        if not hasattr(self, '_xml_attr'):
            self._xml_attr = OrderedDict()
        return self._xml_attr

Eckhart Arnold's avatar
Eckhart Arnold committed
473

474
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=lambda i: i, density=0) -> str:
475 476 477 478 479 480 481 482
        """
        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.

483
        Args:
484
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
485
            open_fn:   (Node->str) A function that returns an opening
486
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
487
            close_fn:  (Node->str) A function that returns a closeF
488
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
489
            data_fn:   (str->str) A function that filters the data string
490 491 492 493 494 495
                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
496 497
        head = open_fn(self)
        tail = close_fn(self)
498 499

        if not self.result:
500
            return head.rstrip() + tail.lstrip()
501

eckhart's avatar
eckhart committed
502
        tail = tail.lstrip(None if density & 2 else '')
503 504 505

        if self.children:
            content = []
506
            for child in self.children:
eckhart's avatar
eckhart committed
507
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn, density).split('\n')
508
                content.append('\n'.join((tab + s) for s in subtree))
eckhart's avatar
eckhart committed
509
            return head + '\n'.join(content) + tail
510

511
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
512 513 514
        if density & 1 and res.find('\n') < 0:  # and head[0] == "<":
            # except for XML, add a gap between opening statement and content
            gap = ' ' if head.rstrip()[-1] != '>' else ''
eckhart's avatar
eckhart committed
515
            return head.rstrip() + gap + data_fn(self.result) + tail.lstrip()
516
        else:
eckhart's avatar
eckhart committed
517
            return head + '\n'.join([tab + data_fn(s) for s in res.split('\n')]) + tail
518

Eckhart Arnold's avatar
Eckhart Arnold committed
519

520 521
    def as_sxpr(self, src: str = None, compact: bool = False, showerrors: bool = True,
                indentation: int = 2) -> str:
522 523 524
        """
        Returns content as S-expression, i.e. in lisp-like form.

525
        Args:
526 527 528
            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.
Eckhart Arnold's avatar
Eckhart Arnold committed
529
            compact:  If True a compact representation is returned where
530
                brackets are omitted and only the indentation indicates the
Eckhart Arnold's avatar
Eckhart Arnold committed
531
                tree structure.
532 533
        """

eckhart's avatar
eckhart committed
534
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
eckhart's avatar
eckhart committed
535
        lbreaks = linebreaks(src) if src else []  # type: List[int]
536

537
        def opening(node) -> str:
eckhart's avatar
eckhart committed
538
            """Returns the opening string for the representation of `node`."""
539
            txt = [left_bracket,  node.tag_name]
540
            # s += " '(pos %i)" % node.add_pos
541
            if hasattr(node, '_xml_attr'):
542
                txt.extend(' `(%s "%s")' % (k, v) for k, v in node.attributes.items())
543
            if src:
eckhart's avatar
eckhart committed
544
                txt.append(" `(pos %i %i %i)" % (node.pos, *line_col(lbreaks, node.pos)))
di68kap's avatar
di68kap committed
545 546
            # if node.error_flag:   # just for debugging error collecting
            #     txt += " HAS ERRORS"
547
            if showerrors and node.errors:
548
                txt.append(" `(err `%s)" % ' '.join(str(err) for err in node.errors))
549
            return "".join(txt) + '\n'
550

eckhart's avatar
eckhart committed
551 552 553
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
554

eckhart's avatar
eckhart committed
555 556 557 558 559
        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'\"')
560

561
        return self._tree_repr(' ' * indentation, opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
562

eckhart's avatar
eckhart committed
563

564
    def as_xml(self, src: str = None, showerrors: bool = True, indentation: int = 2) -> str:
565 566 567
        """
        Returns content as XML-tree.

568
        Args:
569 570 571 572 573
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
        """

574
        def opening(node) -> str:
eckhart's avatar
eckhart committed
575
            """Returns the opening string for the representation of `node`."""            
eckhart's avatar
eckhart committed
576
            txt = ['<', node.tag_name]
577 578
            has_reserved_attrs = hasattr(node, '_xml_attr') \
                and any (r in node.attributes for r in {'err', 'line', 'col'})
di68kap's avatar
di68kap committed
579
            if hasattr(node, '_xml_attr'):
580
                txt.extend(' %s="%s"' % (k, v) for k, v in node.attributes.items())
581
            if src and not has_reserved_attrs:
eckhart's avatar
eckhart committed
582
                txt.append(' line="%i" col="%i"' % line_col(line_breaks, node.pos))
583
            if showerrors and node.errors and not has_reserved_attrs:
eckhart's avatar
eckhart committed
584 585 586
                txt.append(' err="%s"' % ''.join(str(err).replace('"', r'\"')
                                                 for err in node.errors))
            return "".join(txt + [">\n"])
587 588

        def closing(node):
eckhart's avatar
eckhart committed
589
            """Returns the closing string for the representation of `node`."""            
590
            return '\n</' + node.tag_name + '>'
591

592
        line_breaks = linebreaks(src) if src else []
593
        return self._tree_repr(' ' * indentation, opening, closing, density=1)
594

Eckhart Arnold's avatar
Eckhart Arnold committed
595

596
    def select(self, match_function: Callable, include_root: bool=True) -> Iterator['Node']:
eckhart's avatar
eckhart committed
597
        """
598
        Finds nodes in the tree that fulfill a given criterion.
eckhart's avatar
eckhart committed
599

600
        `select` is a generator that yields all nodes for which the
di68kap's avatar
di68kap committed
601
        given `match_function` evaluates to True. The tree is
602 603 604
        traversed pre-order.

        See function `Node.select_by_tag` for some examples.
eckhart's avatar
eckhart committed
605

606 607 608
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
609 610
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
611
        Yields:
612
            Node: All nodes of the tree for which
613 614
            ``match_function(node)`` returns True
        """
615
        if include_root and match_function(self):
616 617 618
            yield self
        else:
            for child in self.children:
619
                for node in child.select(match_function, True):
eckhart's avatar
eckhart committed
620
                    yield node
621

Eckhart Arnold's avatar
Eckhart Arnold committed
622

eckhart's avatar
eckhart committed
623
    def select_by_tag(self, tag_names: Union[str, AbstractSet[str]],
624
                      include_root: bool=True) -> Iterator['Node']:
625
        """
626 627 628 629
        Returns an iterator that runs through all descendants that have one
        of the given tag names.

        Examples::
630

631
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
632
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag("X", False))
633
            ['(X (c "d"))', '(X "F")']
634
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag({"X", "b"}, False))
635
            ['(b "X")', '(X (c "d"))', '(X "F")']
636
            >>> any(tree.select_by_tag('a', False))
637
            False
638
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag('a', True))
639
            ['(a (b "X") (X (c "d")) (e (X "F")))']
640 641
            >>> flatten_sxpr(next(tree.select_by_tag("X", False)).as_sxpr())
            '(X (c "d"))'
642 643

        Args:
644 645 646 647
            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.
648 649 650
        Yields:
            Node: All nodes which have a given tag name.
        """
651
        if isinstance(tag_names, str):
eckhart's avatar
eckhart committed
652
            tag_names = frozenset({tag_names})
653
        return self.select(lambda node: node.tag_name in tag_names, include_root)
654 655


656 657 658 659 660 661 662 663 664 665 666 667 668 669 670
    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


671
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
672 673 674
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
675 676 677
        return sum(child.tree_size() for child in self.children) + 1


di68kap's avatar
di68kap committed
678
class RootNode(Node):
679
    """TODO: Add Documentation!!!
di68kap's avatar
di68kap committed
680

681 682 683
        errors (list):  A list of all errors that have occured so far during
                processing (i.e. parsing, AST-transformation, compiling)
                of this tree.
di68kap's avatar
di68kap committed
684

685 686
        error_flag (int):  the highest warning or error level of all errors
                that occurred.
di68kap's avatar
di68kap committed
687
    """
eckhart's avatar
eckhart committed
688
    def __init__(self, node: Optional[Node] = None) -> 'RootNode':
di68kap's avatar
di68kap committed
689
        super().__init__(ZOMBIE_PARSER, '')
690
        self.all_errors = []
eckhart's avatar
eckhart committed
691
        self.err_nodes_keep = []
di68kap's avatar
di68kap committed
692
        self.error_flag = 0
eckhart's avatar
eckhart committed
693 694
        if node is not None:
            self.swallow(node)
di68kap's avatar
di68kap committed
695

696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719
    # def _propagate_errors(self):
    #     if not self.all_errors or not self.error_propagation:
    #         return
    #     self.all_errors.sort(key=lambda e: e.pos)
    #     i = 0
    #     for leaf in self.select(lambda nd: not nd.children, False):
    #         leaf.errors = []
    #         while i < len(self.all_errors) \
    #                 and leaf.pos <= self.all_errors[i].add_pos < leaf.add_pos + leaf.len:
    #             leaf._errors.append(self.all_errors[i])
    #             i += 1
    #         if i >= len(self.all_errors):
    #             break
    #
    # def _propagate_new_error(self, error):
    #     if self.error_propagation:
    #         for leaf in self.select(lambda nd: not nd.children, True):
    #             if leaf.pos <= error.add_pos < leaf.add_pos + leaf.len:
    #                 leaf._errors.append(error)
    #                 break
    #         else:
    #             assert False, "Error %s at pos %i out of bounds" % (str(error), error.add_pos)

    def swallow(self, node: Node) -> 'RootNode':
di68kap's avatar
di68kap committed
720 721 722 723 724
        self._result = node._result
        self.children = node.children
        self._len = node._len
        self._pos = node._pos
        self.parser = node.parser
725 726
        if hasattr(node, '_xml_attr'):
            self._xml_attr = node._xml_attr
di68kap's avatar
di68kap committed
727
        self._content = node._content
728
        return self
di68kap's avatar
di68kap committed
729

eckhart's avatar
eckhart committed
730 731
    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
732 733 734 735 736 737
        self.all_errors.append(error)
        self.error_flag = max(self.error_flag, error.code)
        node.errors.append(error)
        self.err_nodes_keep.append(node)
        return self

eckhart's avatar
eckhart committed
738
    def new_error(self,
739
                  node: Node,
di68kap's avatar
di68kap committed
740
                  message: str,
di68kap's avatar
di68kap committed
741
                  code: int = Error.ERROR) -> 'RootNode':
di68kap's avatar
di68kap committed
742
        """
eckhart's avatar
eckhart committed
743
        Adds an error to this tree, locating it at a specific node.
di68kap's avatar
di68kap committed
744 745 746 747 748
        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's avatar
eckhart committed
749
        error = Error(message, code, node=node)
eckhart's avatar
eckhart committed
750 751
        self.add_error(node, error)
        return self
di68kap's avatar
di68kap committed
752

eckhart's avatar
eckhart committed
753
    def collect_errors(self) -> List[Error]:
di68kap's avatar
di68kap committed
754 755
        """Returns the list of errors, ordered bv their position.
        """
eckhart's avatar
eckhart committed
756 757 758
        # for node in self.err_nodes:  # lazy evaluation of positions
        #     for err in node.errors:  # moved to error.Error.pos
        #         err.pos = node.pos
759
        self.all_errors.sort(key=lambda e: e.pos)
eckhart's avatar
eckhart committed
760 761
        for node in self.err_nodes_keep:  # redundant: consider removing Error.Error._node_keep
            for error in node.errors:
eckhart's avatar
eckhart committed
762
                assert error._pos < 0 or node.pos <= error._pos <= node.pos + len(node)
763 764
                if error._pos < 0:
                    error._pos = node.pos
eckhart's avatar
eckhart committed
765
        self.err_nodes_keep = []
766
        errors = self.all_errors
eckhart's avatar
eckhart committed
767 768
        # for error in self.all_errors:
        #     _ = error.pos
di68kap's avatar
di68kap committed
769 770 771
        return errors


eckhart's avatar
eckhart committed
772 773 774
ZOMBIE_NODE = Node(ZOMBIE_PARSER, '')


775
def parse_sxpr(sxpr: str) -> Node:
776
    """
777 778 779 780 781
    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.
782 783

    Example:
784
    >>> parse_sxpr("(a (b c))").as_sxpr()
785 786
    '(a\\n    (b\\n        "c"\\n    )\\n)'
    """
787 788
    sxpr = StringView(sxpr).strip()
    mock_parsers = dict()
789

790
    def next_block(s: StringView):
eckhart's avatar
eckhart committed
791 792 793
        """Generator that yields all characters until the next closing bracket
        that does not match an opening bracket matched earlier within the same
        package."""
794
        s = s.strip()
795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813
        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)
814

815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861
    def inner_parser(sxpr: StringView) -> Node:
        if sxpr[0] != '(':
            raise ValueError('"(" expected, not ' + sxpr[:10])
        # assert sxpr[0] == '(', sxpr
        sxpr = sxpr[1:].strip()
        match = sxpr.match(re.compile(r'[\w:]+'))
        if match is None:
            raise AssertionError('Malformed S-expression Node-tagname or identifier expected, '
                                 'not "%s"' % sxpr[:40].replace('\n', ''))
        end = match.end() - sxpr.begin
        tagname = sxpr[:end]
        name, class_name = (tagname.split(':') + [''])[:2]
        sxpr = sxpr[end:].strip()
        attributes = OrderedDict()
        if sxpr[0] == '(':
            result = tuple(inner_parser(block) for block in next_block(sxpr))
        else:
            lines = []
            while sxpr and sxpr[0:1] != ')':
                # parse attributes
                while sxpr[:2] == "`(":
                    i = sxpr.find('"')
                    k = sxpr.find(')')
                    # read very special attribute pos
                    if sxpr[2:5] == "pos" and 0 < i < k:
                        pos = int(sxpr[5:k].strip().split(' ')[0])
                    # ignore very special attribute err
                    elif sxpr[2:5] == "err" and 0 <= sxpr.find('`', 5) < k:
                        m = sxpr.find('(', 5)
                        while m >= 0 and m < k:
                            m = sxpr.find('(', k)
                            k = max(k, sxpr.find(')', max(m, 0)))
                    # read attributes
                    else:
                        attr = sxpr[2:i].strip()
                        value = sxpr[i:k].strip()[1:-1]
                        attributes[attr] = value
                    sxpr = sxpr[k+1:].strip()
                # parse content
                for qtmark in ['"""', "'''", '"', "'"]:
                    match = sxpr.match(re.compile(qtmark + r'.*?' + qtmark, re.DOTALL))
                    if match:
                        end = match.end() - sxpr.begin
                        i = len(qtmark)
                        lines.append(str(sxpr[i:end - i]))
                        sxpr = sxpr[end:].strip()
                        break
862
                else:
863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880
                    match = sxpr.match(re.compile(r'(?:(?!\)).)*', re.DOTALL))
                    end = match.end() - sxpr.begin
                    lines.append(str(sxpr[:end]))
                    sxpr = sxpr[end:]
            result = "\n".join(lines)
        node = Node(mock_parsers.setdefault(tagname, MockParser(name, ':' + class_name)), result)
        if attributes:
            node.attributes.update(attributes)
        return node

    return inner_parser(sxpr)


def parse_xml(xml: str) -> Node:
    """
    Generates a tree of nodes from a (Pseudo-)XML-source.
    """
    xml = StringView(xml)
881
    PlainText = MockParser('', ':PlainText')
882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
    mock_parsers = {':PlainText': PlainText}

    def parse_attributes(s: StringView) -> Tuple[StringView, OrderedDict]:
        """Parses a sqeuence of XML-Attributes. Returns the string-slice
        beginning after the end of the attributes."""
        attributes = OrderedDict()
        restart = 0
        for match in s.finditer(re.compile(r'\s*(?P<attr>\w+)\s*=\s*"(?P<value>.*)"\s*')):
            d = match.groupdict()
            attributes[d['attr']] = d['value']
            restart = match.end() - s.begin
        return (s[restart:], attributes)

    def parse_opening_tag(s: StringView) -> Tuple[StringView, str, OrderedDict, bool]:
        """Parses an opening tag. Returns the string segment following the
        the opening tag, the tag name, a dictionary of attributes and
        a flag indicating whether the tag is actually a solitary tag as
        indicated by a slash at the end, i.e. <br/>."""
        match = s.match(re.compile(r'<\s*(?P<tagname>[\w:]+)\s*'))
        assert match
        tagname = match.groupdict()['tagname']
        s, attributes = parse_attributes(s[match.end() - s.begin:])
        i = s.find('>')
        assert i >= 0
906
        return s[i+1:], tagname, attributes, s[i-1] == "/"
907 908

    def parse_closing_tag(s: StringView) -> Tuple[StringView, str]:
909
        """Parses a closing tag and returns the string segment, just after
910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946
        the closing tag."""
        match = s.match(re.compile(r'</\s*(?P<tagname>[\w:]+)>'))
        assert match
        tagname = match.groupdict()['tagname']
        return s[match.end() - s.begin:], tagname

    def parse_leaf_content(s: StringView) -> Tuple[StringView, str]:
        """Parses a piece of the content of a tag, just until the next opening,
        closing or solitary tag is reached."""
        i = 0
        while s[i] != "<" or s[max(0, i-1)] == "\\":
            i = s.find("<", i)
        return s[i:], s[:i]

    def parse_full_content(s: StringView) -> Tuple[StringView, Node]:
        """Parses the full content of a tag, starting right at the beginning
        of the opening tag and ending right after the closing tag.
        """
        result = []
        s, tagname, attributes, solitary = parse_opening_tag(s)
        name, class_name = (tagname.split(":") + [''])[:2]
        if not solitary:
            while s and not s[:2] == "</":
                s, leaf = parse_leaf_content(s)
                if not s.match(re.compile("\s*$")):
                    result.append(Node(PlainText, leaf))
                if s[:1] == "<" and s[:2] != "</":
                    s, child = parse_full_content(s)
                    result.append(child)
            s, closing_tagname = parse_closing_tag(s)
            assert tagname == closing_tagname
        if len(result) == 1 and isinstance(result[0].parser == PlainText):
            result = result[0].result
        else:
            result = tuple(result)
        return Node(mock_parsers.setdefault(tagname, MockParser(name, ":" + class_name)), result)

947 948 949
    match_header = xml.search(re.compile(r'<(?!\?)'))
    start = match_header.start() if match_header else 0
    return parse_full_content(xml[start:])
950

951