syntaxtree.py 38.9 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
    i.e. only whitespace within leaf-nodes is preserved.
197
198
    A more precise alternative to `flatten_xml` is to use Node.as_xml()
    ans passing a set containing the top level tag to parameter `inline_tags`.
199
    """
200
201
202
203
    # 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']
204
    return re.sub(r'\s+(?=<[\w:])', '', re.sub(r'(?P<closing_tag></:?\w+>)\s+', tag_only, xml))
205
206


Eckhart Arnold's avatar
Eckhart Arnold committed
207
class Node(collections.abc.Sized):
208
209
210
    """
    Represents a node in the concrete or abstract syntax tree.

211
212
    TODO: Add some documentation and doc-tests here...

213
    Attributes:
214
215
        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
216

217
218
219
        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.
220

221
222
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
223

eckhart's avatar
eckhart committed
224
225
226
227
        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
228
        parser (Parser):  The parser which generated this node.
229
230
            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
231
232
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
233
            example by calling ``isinstance(node.parer, ...)``.
234

235
236
237
        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
238
            the length before AST-transformation and will never change
239
            through AST-transformation. READ ONLY!
240

241
242
        pos (int):  the position of the node within the parsed text.

Eckhart Arnold's avatar
Eckhart Arnold committed
243
            The value of ``pos`` is -1 meaning invalid by default.
244
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
245
            nodes relative to this value.
246
247

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
248
            pos value of the root node should be set to 0 right
249
250
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
251
            Other than that, this value should be considered READ ONLY.
252
253
            At any rate, it should only be reassigned during the parsing
            stage and never during or after the AST-transformation.
254

255
256
        errors (list):  A list of all errors that occured on this node.

257
258
        attr (dict): An optional dictionary of XML-attr. This
            dictionary is created lazily upon first usage. The attr
259
260
            will only be shown in the XML-Representation, not in the
            S-Expression-output.
261
    """
262

Eckhart Arnold's avatar
Eckhart Arnold committed
263
    __slots__ = '_result', 'children', '_len', '_pos', 'parser', 'errors', '_xml_attr', '_content'
264

265
266
267
    def __init__(self, parser, result: ResultType, leafhint: bool = False) -> None:
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
268
269
        that generated the node and the parser's result.
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
270
        self.errors = []                # type: List[Error]
eckhart's avatar
eckhart committed
271
        self._pos = -1                  # type: int
272
        # Assignment to self.result initializes the attr _result, children and _len
di68kap's avatar
di68kap committed
273
        # The following if-clause is merely an optimization, i.e. a fast-path for leaf-Nodes
274
        if leafhint:
eckhart's avatar
eckhart committed
275
            self._result = result       # type: StrictResultType
eckhart's avatar
eckhart committed
276
            self._content = None        # type: Optional[str]
277
            self.children = NoChildren  # type: ChildrenType
278
            self._len = -1              # type: int  # lazy evaluation
279
280
        else:
            self.result = result
281
282
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
283

284
    def __str__(self):
285
        s = "".join(str(child) for child in self.children) if self.children else self.content
eckhart's avatar
eckhart committed
286
        if self.errors:
287
            return ' <<< Error on "%s" | %s >>> ' % \
eckhart's avatar
eckhart committed
288
                   (s, '; '.join(e.message for e in self.errors))
289
        return s
290

Eckhart Arnold's avatar
Eckhart Arnold committed
291

292
293
294
295
296
297
    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)
298

Eckhart Arnold's avatar
Eckhart Arnold committed
299

300
    def __len__(self):
301
        if self._len < 0:
di68kap's avatar
di68kap committed
302
            self._len = sum(len(child) for child in self.children) \
303
                if self.children else len(self._result)
304
305
306
307
308
309
310
311
        return self._len


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


312
    def __eq__(self, other):
313
314
315
316
        """
        Equality of nodes: Two nodes are considered as equal, if their tag
        name is the same and if their results are equal.
        """
317
        return self.tag_name == other.tag_name and self.result == other.result
318

Eckhart Arnold's avatar
Eckhart Arnold committed
319

320
    def __hash__(self):
321
        return hash(self.tag_name)
322

Eckhart Arnold's avatar
Eckhart Arnold committed
323

324
325
326
    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
327
        an integer or the first child node with the given tag name. Examples::
328

329
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
330
331
            >>> flatten_sxpr(tree[0].as_sxpr())
            '(b "X")'
332
333
            >>> flatten_sxpr(tree["X"].as_sxpr())
            '(X (c "d"))'
334
335
336
337

        Args:
            index_or_tagname(str): Either an index of a child node or a
                tag name.
338
        Returns:
339
340
            Node: All nodes which have a given tag name.
        """
341
342
343
        if self.children:
            if isinstance(index_or_tagname, int):
                return self.children[index_or_tagname]
344
            else:
345
346
347
348
349
                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!')
350
351
352
353


    def __contains__(self, tag_name: str) -> bool:
        """
354
        Returns true if a child with the given tag name exists.
355
        Args:
356
357
            tag_name (str): tag_name which will be searched among to immediate
                descendants of this node.
358
359
360
361
        Returns:
            bool:  True, if at least one descendant node with the given tag
                name exists, False otherwise
        """
362
363
364
365
366
        # assert isinstance(tag_name, str)
        if self.children:
            for child in self.children:
                if child.tag_name == tag_name:
                    return True
367
            return False
368
        raise ValueError('Leave node cannot contain other nodes')
369
        # generator = self.select_by_tag(tag_name, False)
370
371
372
373
374
        # try:
        #     generator.__next__()
        #     return True
        # except StopIteration:
        #     return False
375
376


377
378
379
380
381
382
383
384
385
386
387
388
389
390
    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


391
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
392
    def tag_name(self) -> str:
393
394
395
396
397
398
        """
        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`.
        """
399
        return self.parser.name or self.parser.ptype
400

Eckhart Arnold's avatar
Eckhart Arnold committed
401

402
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
403
    def result(self) -> StrictResultType:
404
405
406
407
408
        """
        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.
        """
409
410
        return self._result

411

412
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
413
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
414
        # # made obsolete by static type checking with mypy
415
416
417
        # 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
418
419
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
420
421
        self._len = -1        # lazy evaluation
        self._content = None
422
423
424
425
426
427
428
429
430
        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
431
                self._result = result
432

433
434

    @property
eckhart's avatar
eckhart committed
435
    def content(self) -> str:
436
        """
di68kap's avatar
di68kap committed
437
438
439
        Returns content as string, omitting error messages. If the node has
        child-nodes, the string content of the child-nodes is recursively read
        and then concatenated.
440
        """
441
442
443
444
        if self._content is None:
            if self.children:
                self._content = "".join(child.content for child in self.children)
            else:
445
                # self._content = self._result
446
447
448
                self._content = str(self._result)
                self._result = self._content  # self._result might be more efficient as a string!?
        return self._content
449
450


di68kap's avatar
di68kap committed
451
452
453
454
455
    @content.setter
    def content(self, content: str):
        self.result = content


456
457
458
459
460
461
462
463
464
    @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))


465
    @property
466
    def pos(self) -> int:
eckhart's avatar
eckhart committed
467
468
        """Returns the position of the Node's content in the source text."""
        if self._pos < 0:
469
            raise AssertionError("Position value not initialized!")
470
471
        return self._pos

eckhart's avatar
eckhart committed
472

eckhart's avatar
eckhart committed
473
    def init_pos(self, pos: int) -> 'Node':
eckhart's avatar
eckhart committed
474
475
476
477
478
479
480
481
482
        """
        (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
483
484
        assert self._pos < 0 or self.pos == pos, str("pos mismatch %i != %i" % (self._pos, pos))
        self._pos = pos
485
        # recursively adjust pos-values of all children
eckhart's avatar
eckhart committed
486
        offset = self.pos
487
        for child in self.children:
eckhart's avatar
eckhart committed
488
            child.init_pos(offset)
eckhart's avatar
eckhart committed
489
490
491
            offset = child.pos + len(child)
        return self

492

493
    @property
494
    def attr(self):
495
        """
496
        Returns a dictionary of XML-attr attached to the node.
497
        """
498
499
500
501
        if not hasattr(self, '_xml_attr'):
            self._xml_attr = OrderedDict()
        return self._xml_attr

Eckhart Arnold's avatar
Eckhart Arnold committed
502

503
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=lambda i: i,
504
                   density=0, inline=False, inline_fn=lambda node: False) -> str:
505
506
507
508
509
510
511
512
        """
        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.

513
        Args:
514
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
515
            open_fn:   (Node->str) A function that returns an opening
516
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
517
            close_fn:  (Node->str) A function that returns a closeF
518
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
519
            data_fn:   (str->str) A function that filters the data string
520
521
522
523
524
525
                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
526
527
        head = open_fn(self)
        tail = close_fn(self)
528
529

        if not self.result:
530
            return head.rstrip() + tail.lstrip()
531

eckhart's avatar
eckhart committed
532
        tail = tail.lstrip(None if density & 2 else '')
533

534
        inline = inline or inline_fn(self)
535
536
537
538
539
        if inline:
            head = head.rstrip()
            tail = tail.lstrip()
            usetab, sep = '', ''
        else:
eckhart's avatar
eckhart committed
540
541
            usetab = tab if head else ''    # no indentation if tag is already omitted
            sep = '\n'
542

543
544
        if self.children:
            content = []
545
            for child in self.children:
546
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn,
547
                                           density, inline, inline_fn)
eckhart's avatar
eckhart committed
548
549
550
                if subtree:
                    subtree = [subtree] if inline else subtree.split('\n')
                    content.append((sep + usetab).join(s for s in subtree))
551
            return head + usetab + (sep + usetab).join(content) + tail
552

553
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
eckhart's avatar
eckhart committed
554
        if not inline and not head:
eckhart's avatar
eckhart committed
555
            # strip whitespace for omitted non inline node, e.g. CharData in mixed elements
eckhart's avatar
eckhart committed
556
            res = res.strip()
557
558
        if density & 1 and res.find('\n') < 0:  # and head[0] == "<":
            # except for XML, add a gap between opening statement and content
559
            gap = ' ' if not inline and head and head.rstrip()[-1:] != '>' else ''
eckhart's avatar
eckhart committed
560
            return head.rstrip() + gap + data_fn(res) + tail.lstrip()
561
        else:
562
            return head + '\n'.join([usetab + data_fn(s) for s in res.split('\n')]) + tail
563

Eckhart Arnold's avatar
Eckhart Arnold committed
564

565
566
567
    def as_sxpr(self, src: str = None,
                showerrors: bool = True,
                indentation: int = 2,
568
                compact: bool = False) -> str:
569
570
571
        """
        Returns content as S-expression, i.e. in lisp-like form.

572
        Args:
573
574
575
            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.
576
577
578
            showerrors: If True, error messages will be shown.
            indentation: The number of whitespaces for indentation
            compact:  If True, a compact representation is returned where
579
                brackets are omitted and only the indentation indicates the
Eckhart Arnold's avatar
Eckhart Arnold committed
580
                tree structure.
581
582
        """

eckhart's avatar
eckhart committed
583
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
eckhart's avatar
eckhart committed
584
        lbreaks = linebreaks(src) if src else []  # type: List[int]
585

586
        def opening(node) -> str:
eckhart's avatar
eckhart committed
587
            """Returns the opening string for the representation of `node`."""
588
            txt = [left_bracket,  node.tag_name]
589
            # s += " '(pos %i)" % node.add_pos
590
            if hasattr(node, '_xml_attr'):
591
                txt.extend(' `(%s "%s")' % (k, v) for k, v in node.attr.items())
592
            if src:
eckhart's avatar
eckhart committed
593
                txt.append(" `(pos %i %i %i)" % (node.pos, *line_col(lbreaks, node.pos)))
594
            if showerrors and node.errors:
595
                txt.append(" `(err `%s)" % ' '.join(str(err) for err in node.errors))
596
            return "".join(txt) + '\n'
597

eckhart's avatar
eckhart committed
598
599
600
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
601

eckhart's avatar
eckhart committed
602
603
604
605
606
        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'\"')
607

608
        return self._tree_repr(' ' * indentation, opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
609

eckhart's avatar
eckhart committed
610

611
612
613
614
615
616
    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:
617
618
619
        """
        Returns content as XML-tree.

620
        Args:
621
622
623
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
624
625
            showerrors: If True, error messages will be shown.
            indentation: The number of whitespaces for indentation
626
627
628
            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
629
                neither the opening tag nor its attr nor the closing tag. This
630
631
632
                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.
633
634
            empty_tags:  A set of tags which shall be rendered as empty elements, e.g.
                "<empty/>" instead of "<empty><empty>".
635
636
        """

637
        def opening(node) -> str:
638
639
640
            """Returns the opening string for the representation of `node`."""
            if node.tag_name in omit_tags:
                return ''
eckhart's avatar
eckhart committed
641
            txt = ['<', node.tag_name]
642
            has_reserved_attrs = hasattr(node, '_xml_attr') \
643
                and any (r in node.attr for r in {'err', 'line', 'col'})
di68kap's avatar
di68kap committed
644
            if hasattr(node, '_xml_attr'):
645
                txt.extend(' %s="%s"' % (k, v) for k, v in node.attr.items())
646
            if src and not has_reserved_attrs:
eckhart's avatar
eckhart committed
647
                txt.append(' line="%i" col="%i"' % line_col(line_breaks, node.pos))
648
            if showerrors and node.errors and not has_reserved_attrs:
eckhart's avatar
eckhart committed
649
650
                txt.append(' err="%s"' % ''.join(str(err).replace('"', r'\"')
                                                 for err in node.errors))
651
652
653
            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
654
                ending = "/>\n" if not node.tag_name[0] == '?' else "?>\n"
655
656
657
            else:
                ending = ">\n"
            return "".join(txt + [ending])
658
659

        def closing(node):
660
            """Returns the closing string for the representation of `node`."""
661
            if node.tag_name in omit_tags or node.tag_name in empty_tags:
662
                return ''
663
            return ('\n</') + node.tag_name + '>'
664

665
666
667
668
669
        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.
            """
670
            return node.tag_name in inline_tags or (hasattr(node, '_xml_attr') \
671
                                                    and node.attr.get('xml:space', 'default') == 'preserve')
672

673
        line_breaks = linebreaks(src) if src else []
674
675
        return self._tree_repr(' ' * indentation, opening, closing,
                               density=1, inline_fn=inlining)
676

Eckhart Arnold's avatar
Eckhart Arnold committed
677

678
    def select(self, match_function: Callable, include_root: bool=False) -> Iterator['Node']:
eckhart's avatar
eckhart committed
679
        """
680
        Finds nodes in the tree that fulfill a given criterion.
eckhart's avatar
eckhart committed
681

682
        `select` is a generator that yields all nodes for which the
di68kap's avatar
di68kap committed
683
        given `match_function` evaluates to True. The tree is
684
685
686
        traversed pre-order.

        See function `Node.select_by_tag` for some examples.
eckhart's avatar
eckhart committed
687

688
689
690
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
691
692
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
693
        Yields:
694
            Node: All nodes of the tree for which
695
696
            ``match_function(node)`` returns True
        """
697
        if include_root and match_function(self):
698
            yield self
eckhart's avatar
eckhart committed
699
700
701
        for child in self.children:
            for node in child.select(match_function, True):
                yield node
702

Eckhart Arnold's avatar
Eckhart Arnold committed
703

eckhart's avatar
eckhart committed
704
    def select_by_tag(self, tag_names: Union[str, AbstractSet[str]],
705
                      include_root: bool=False) -> Iterator['Node']:
706
        """
707
708
709
710
        Returns an iterator that runs through all descendants that have one
        of the given tag names.

        Examples::
711

712
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
713
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag("X", False))
714
            ['(X (c "d"))', '(X "F")']
715
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag({"X", "b"}, False))
716
            ['(b "X")', '(X (c "d"))', '(X "F")']
717
            >>> any(tree.select_by_tag('a', False))
718
            False
719
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag('a', True))
720
            ['(a (b "X") (X (c "d")) (e (X "F")))']
721
722
            >>> flatten_sxpr(next(tree.select_by_tag("X", False)).as_sxpr())
            '(X (c "d"))'
723
724

        Args:
725
726
727
728
            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.
729
730
731
        Yields:
            Node: All nodes which have a given tag name.
        """
732
        if isinstance(tag_names, str):
eckhart's avatar
eckhart committed
733
            tag_names = frozenset({tag_names})
734
        return self.select(lambda node: node.tag_name in tag_names, include_root)
735
736


737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
    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


752
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
753
754
755
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
756
757
758
        return sum(child.tree_size() for child in self.children) + 1


di68kap's avatar
di68kap committed
759
class RootNode(Node):
760
    """TODO: Add Documentation!!!
di68kap's avatar
di68kap committed
761

Eckhart Arnold's avatar
Eckhart Arnold committed
762
        all_errors (list):  A list of all errors that have occured so far during
763
764
                processing (i.e. parsing, AST-transformation, compiling)
                of this tree.
di68kap's avatar
di68kap committed
765

766
767
        error_flag (int):  the highest warning or error level of all errors
                that occurred.
di68kap's avatar
di68kap committed
768
    """
eckhart's avatar
eckhart committed
769
    def __init__(self, node: Optional[Node] = None) -> 'RootNode':
di68kap's avatar
di68kap committed
770
        super().__init__(ZOMBIE_PARSER, '')
771
        self.all_errors = []
di68kap's avatar
di68kap committed
772
        self.error_flag = 0
eckhart's avatar
eckhart committed
773
774
        if node is not None:
            self.swallow(node)
775
776
777
778
        # customization for XML-Representation
        self.inline_tags = set()
        self.omit_tags = set()
        self.empty_tags = set()
di68kap's avatar
di68kap committed
779

780
    def swallow(self, node: Node) -> 'RootNode':
781
782
783
784
785
786
787
788
789
790
        """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
791
792
793
794
795
        self._result = node._result
        self.children = node.children
        self._len = node._len
        self._pos = node._pos
        self.parser = node.parser
796
797
        if hasattr(node, '_xml_attr'):
            self._xml_attr = node._xml_attr
di68kap's avatar
di68kap committed
798
        self._content = node._content
799
        return self
di68kap's avatar
di68kap committed
800

eckhart's avatar
eckhart committed
801
802
    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
803
804
805
806
807
        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
808
    def new_error(self,
809
                  node: Node,
di68kap's avatar
di68kap committed
810
                  message: str,
di68kap's avatar
di68kap committed
811
                  code: int = Error.ERROR) -> 'RootNode':
di68kap's avatar
di68kap committed
812
        """
eckhart's avatar
eckhart committed
813
        Adds an error to this tree, locating it at a specific node.
di68kap's avatar
di68kap committed
814
815
816
817
818
        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
819
        error = Error(message, node.pos, code)
eckhart's avatar
eckhart committed
820
821
        self.add_error(node, error)
        return self
di68kap's avatar
di68kap committed
822

eckhart's avatar
eckhart committed
823
    def collect_errors(self) -> List[Error]:
di68kap's avatar
di68kap committed
824
825
        """Returns the list of errors, ordered bv their position.
        """
826
        self.all_errors.sort(key=lambda e: e.pos)
Eckhart Arnold's avatar
Eckhart Arnold committed
827
        return self.all_errors
di68kap's avatar
di68kap committed
828

829
830
831
832
833
834
835
836
    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
837

eckhart's avatar
eckhart committed
838
839
840
ZOMBIE_NODE = Node(ZOMBIE_PARSER, '')


841
def parse_sxpr(sxpr: str) -> Node:
842
    """
843
844
845
846
847
    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.
848
849

    Example:
850
    >>> parse_sxpr("(a (b c))").as_sxpr()
851
    '(a\\n  (b\\n    "c"\\n  )\\n)'
852
    """
853
854
    sxpr = StringView(sxpr).strip()
    mock_parsers = dict()
855

856
    def next_block(s: StringView):
eckhart's avatar
eckhart committed
857
858
859
        """Generator that yields all characters until the next closing bracket
        that does not match an opening bracket matched earlier within the same
        package."""
860
        s = s.strip()
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
        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)
880

881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
    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] != ')':
900
                # parse attr
901
902
903
904
905
906
907
908
909
910
911
912
                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)))
913
                    # read attr
914
915
916
917
918
919
920
921
922
923
924
925
926
927
                    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
928
                else:
929
930
931
932
933
934
935
                    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:
936
            node.attr.update(attributes)
937
938
939
940
941
        return node

    return inner_parser(sxpr)


di68kap's avatar
di68kap committed
942
943
944
RX_WHITESPACE_TAIL = re.compile(r'\s*$')


945
946
947
948
949
def parse_xml(xml: str) -> Node:
    """
    Generates a tree of nodes from a (Pseudo-)XML-source.
    """
    xml = StringView(xml)
950
951
    PlainText = MockParser('', TOKEN_PTYPE)
    mock_parsers = {TOKEN_PTYPE: PlainText}
952
953
954

    def parse_attributes(s: StringView) -> Tuple[StringView, OrderedDict]:
        """Parses a sqeuence of XML-Attributes. Returns the string-slice
955
        beginning after the end of the attr."""
956
957
958
959
960
961
962
963
964
965
        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']