syntaxtree.py 19.9 KB
Newer Older
1
"""syntaxtree.py - syntax tree classes for DHParser
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

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.
"""

Eckhart Arnold's avatar
Eckhart Arnold committed
19
import collections.abc
20
import copy
21
import os
22
23
from functools import partial

24
25
26
27
try:
    import regex as re
except ImportError:
    import re
28
29
try:
    from typing import AbstractSet, Any, ByteString, Callable, cast, Container, Dict, \
Eckhart Arnold's avatar
Eckhart Arnold committed
30
        Iterator, Iterable, List, NamedTuple, Sequence, Union, Text, Tuple, Hashable
31
32
except ImportError:
    from .typing34 import AbstractSet, Any, ByteString, Callable, cast, Container, Dict, \
Eckhart Arnold's avatar
Eckhart Arnold committed
33
        Iterator, Iterable, List, NamedTuple, Sequence, Union, Text, Tuple, Hashable
34

35
from DHParser.toolkit import is_logging, log_dir, identity
36
from DHParser.error import Error, linebreaks, line_col
37
38
39
40
41
try:
    import pyximport; pyximport.install()
    from DHParser.cstringview import StringView
except ImportError:
    from DHParser.stringview import StringView
42

43
44
45
46
47
48
49
__all__ = ('ParserBase',
           'WHITESPACE_PTYPE',
           'TOKEN_PTYPE',
           'MockParser',
           'ZombieParser',
           'ZOMBIE_PARSER',
           'Node',
50
51
           'mock_syntax_tree',
           'TransformationFunc')
Eckhart Arnold's avatar
Eckhart Arnold committed
52
53


54
55
56
57
58
59
60
61
62
63
64
65
66
67
#######################################################################
#
# 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()):
68
        self._name = name  # type: str
69
70
71
72
73
74
75
76
        self._ptype = ':' + self.__class__.__name__  # type: str

    def __repr__(self):
        return self.name + self.ptype

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

77
78
79
80
    @property
    def name(self):
        return self._name

81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
    @property
    def ptype(self) -> str:
        return self._ptype

    @property
    def repr(self) -> str:
        return self.name if self.name else repr(self)


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] == ':'
106
        super().__init__(name)
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
        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
#
#######################################################################


149
ChildrenType = Tuple['Node', ...]
150
151
StrictResultType = Union[ChildrenType, StringView, str]
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
152
153


Eckhart Arnold's avatar
Eckhart Arnold committed
154
155
def flatten_sxpr(sxpr: str) -> str:
    """Returns S-expression `sxpr` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
156
157
158
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
159
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
160
161
162
163
164
    '(a (b c))'
    """
    return re.sub('\s(?=\))', '', re.sub('\s+', ' ', sxpr)).strip()


Eckhart Arnold's avatar
Eckhart Arnold committed
165
class Node(collections.abc.Sized):
166
167
168
169
170
171
172
173
174
175
176
    """
    Represents a node in the concrete or abstract syntax tree.

    Attributes:
        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
        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.
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
177
178
179
180
181
182
        parser (Parser):  The parser which generated this node. 
            WARNING: In case you use mock syntax trees for testing or
            parser replacement during the AST-transformation: DO NOT
            rely on this being a real parser object in any phase after 
            parsing (i.e. AST-transformation and compiling), for 
            example by calling ``isinstance(node.parer, ...)``.
183
184
        errors (list):  A list of parser- or compiler-errors:
            tuple(position, string) attached to this node
185
186
187
        error_flag (int):  0 if no error occurred in either the node
            itself or any of its descendants. Otherwise contains the
            highest warning or error level or all errors that occurred.
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
        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
            the length before AST-transformation ans will never change
            through AST-transformation. READ ONLY!
        pos (int):  the position of the node within the parsed text.

            The value of ``pos`` is -1 meaning invalid by default. 
            Setting this value will set the positions of all child
            nodes relative to this value.  

            To set the pos values of all nodes in a syntax tree, the
            pos value of the root node should be set to 0 right 
            after parsing.

            Other than that, this value should be considered READ ONLY. 
            At any rate, it should only be reassigned only during
            parsing stage and never during or after the
            AST-transformation.
    """
208

209
210
    __slots__ = ['_result', 'children', '_errors', '_len', '_pos', 'parser', 'error_flag']

211

Eckhart Arnold's avatar
Eckhart Arnold committed
212
    def __init__(self, parser, result: ResultType) -> None:
213
214
215
        """Initializes the ``Node``-object with the ``Parser``-Instance
        that generated the node and the parser's result.
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
216
        # self._result = ''  # type: StrictResultType
217
        # self.children = ()  # type: ChildrenType
218
        self.error_flag = 0   # type: bool
219
        self._errors = []  # type: List[Error]
220
        self.result = result
Eckhart Arnold's avatar
Eckhart Arnold committed
221
        self._len = len(self._result) if not self.children else \
222
            sum(child._len for child in self.children)  # type: int
Eckhart Arnold's avatar
Eckhart Arnold committed
223
        # self.pos: int  = 0  # continuous updating of pos values wastes a lot of time
224
        self._pos = -1  # type: int
225
226
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
227

228
229
    def __str__(self):
        if self.children:
230
            return "".join(str(child) for child in self.children)
231
232
233
        elif isinstance(self.result, StringView):
            self.result = str(self.result)
        return self.result
234

Eckhart Arnold's avatar
Eckhart Arnold committed
235

236
237
238
239
240
241
    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)
242

Eckhart Arnold's avatar
Eckhart Arnold committed
243

244
245
246
247
248
249
250
251
252
    def __len__(self):
        return self._len


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


253
    def __eq__(self, other):
254
255
        # return str(self.parser) == str(other.parser) and self.result == other.result
        return self.tag_name == other.tag_name and self.result == other.result
256

Eckhart Arnold's avatar
Eckhart Arnold committed
257

258
    def __hash__(self):
259
        return hash(self.tag_name)
260

Eckhart Arnold's avatar
Eckhart Arnold committed
261

262
263
264
265
266
267
    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
268

269
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
270
    def tag_name(self) -> str:
271
        return self.parser.name or self.parser.ptype
272

Eckhart Arnold's avatar
Eckhart Arnold committed
273

274
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
275
    def result(self) -> StrictResultType:
276
277
278
        return self._result

    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
279
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
280
        # # made obsolete by static type checking with mypy
281
282
283
        # 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
284
285
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
286
287
288
        self._result = (result,) if isinstance(result, Node) else result or ''  # type: StrictResultType
        # self._result = (result,) if isinstance(result, Node) else str(result) \
        #     if isinstance(result, StringView) else result or ''  # type: StrictResultType
289
        self.children = cast(ChildrenType, self._result) \
Eckhart Arnold's avatar
Eckhart Arnold committed
290
            if isinstance(self._result, tuple) else cast(ChildrenType, ())  # type: ChildrenType
291
292
293
        if self.children:
            self.error_flag = max(self.error_flag,
                                  max(child.error_flag for child in self.children))  # type: bool
294
295

    @property
296
    def pos(self) -> int:
297
298
299
300
        assert self._pos >= 0, "position value not initialized!"
        return self._pos

    @pos.setter
301
    def pos(self, pos: int):
302
303
        self._pos = pos
        offset = 0
304
        # recursively adjust pos-values of all children
305
306
        for child in self.children:
            child.pos = pos + offset
307
            offset += len(child)
308
309
310
        # add pos-values to Error-objects
        for err in self._errors:
            err.pos = pos
311

Eckhart Arnold's avatar
Eckhart Arnold committed
312

313
    @property
314
    def errors(self) -> List[Error]:
315
316
        return self._errors.copy()

317
    def add_error(self, message: str, level: int = Error.ERROR, code: Hashable = 0) -> 'Node':
Eckhart Arnold's avatar
Eckhart Arnold committed
318
        self._errors.append(Error(message, level, code))
319
        self.error_flag = max(self.error_flag, self._errors[-1].level)
Eckhart Arnold's avatar
Eckhart Arnold committed
320
321
        return self

322
323
    def collect_errors(self, document: Union[StringView, str] = '', clear_errors=False) -> List[
        Error]:
Eckhart Arnold's avatar
Eckhart Arnold committed
324
        """
325
        Recursively adds line- and column-numbers to all error objects.
Eckhart Arnold's avatar
Eckhart Arnold committed
326
327
328
329
        Returns all errors of this node or any child node in the form
        of a set of tuples (position, error_message), where position
        is always relative to this node.
        """
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
        if self.error_flag:
            lbreaks = linebreaks(document) if document else []
            return self._collect_errors(lbreaks, clear_errors)
        else:
            return []

    def _collect_errors(self, lbreaks: List[int] = [], clear_errors=False) -> List[Error]:
        if self.error_flag:
            errors = self.errors
            if lbreaks:
                for err in errors:
                    err.pos = self.pos
                    err.line, err.column = line_col(lbreaks, err.pos)
            if clear_errors:
                self._errors = []
                self.error_flag = 0
            if self.children:
                for child in self.children:
                    errors.extend(child._collect_errors(lbreaks, clear_errors))
            return errors
        else:
            return []
352

Eckhart Arnold's avatar
Eckhart Arnold committed
353

354
    def _tree_repr(self, tab, openF, closeF, dataF=identity, density=0) -> str:
355
356
357
358
359
360
361
362
        """
        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.

363
        Args:
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
            tab (str):  The indentation string, e.g. '\t' or '    '
            openF:  (Node->str) A function that returns an opening
                string (e.g. an XML-tag_name) for a given node
            closeF:  (Node->str) A function that returns a closeF
                string (e.g. an XML-tag_name) for a given node.
            dataF:  (str->str) A function that filters the data string
                before printing, e.g. to add quotation marks

        Returns (str):
            A string that contains a (serialized) tree representation
            of the node and its children.
        """
        head = openF(self)
        tail = closeF(self)

        if not self.result:
380
            return head.rstrip() + tail.lstrip()
381

382
        D = None if density & 2 else ''
383
384
385

        if self.children:
            content = []
386
            for child in self.children:
387
                subtree = child._tree_repr(tab, openF, closeF, dataF, density).split('\n')
388
                content.append('\n'.join((tab + s) for s in subtree))
389
            return head + '\n'.join(content) + tail.lstrip(D)
390

391
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
392
393
394
395
        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 ''
            return head.rstrip() + gap + dataF(self.result) + tail.lstrip()
396
        else:
397
            return head + '\n'.join([tab + dataF(s) for s in res.split('\n')]) + tail.lstrip(D)
398

Eckhart Arnold's avatar
Eckhart Arnold committed
399

400
    def as_sxpr(self, src: str=None, compact: bool=False) -> str:
401
402
403
        """
        Returns content as S-expression, i.e. in lisp-like form.

404
        Args:
405
406
407
            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
408
409
410
            compact:  If True a compact representation is returned where
                brackets are ommited and only the indentation indicates the
                tree structure.
411
412
        """

413
414
        lB, rB, D = ('', '', 1) if compact else ('(', '\n)', 0)

415
        def opening(node) -> str:
416
            s = lB + node.tag_name
417
418
            # s += " '(pos %i)" % node.pos
            if src:
419
                s += " '(pos %i " % node.pos  # + " %i %i)" % line_col(src, node.pos)
420
421
422
            if node.errors:
                s += " '(err '(%s))" % ' '.join(str(err).replace('"', r'\"')
                                                for err in node.errors)
423
            return s + '\n'
424
425
426
427
428
429

        def pretty(s):
            return '"%s"' % s if s.find('"') < 0 \
                else "'%s'" % s if s.find("'") < 0 \
                else '"%s"' % s.replace('"', r'\"')

430
        return self._tree_repr('    ', opening, lambda node: rB, pretty, density=D)
431

Eckhart Arnold's avatar
Eckhart Arnold committed
432

433
    def as_xml(self, src: str=None) -> str:
434
435
436
        """
        Returns content as XML-tree.

437
        Args:
438
439
440
441
442
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
        """

443
        def opening(node) -> str:
444
445
446
447
448
449
            s = '<' + node.tag_name
            # s += ' pos="%i"' % node.pos
            if src:
                s += ' line="%i" col="%i"' % line_col(src, node.pos)
            if node.errors:
                s += ' err="%s"' % ''.join(str(err).replace('"', r'\"') for err in node.errors)
450
            return s + ">\n"
451
452

        def closing(node):
453
            return '\n</' + node.tag_name + '>'
454

455
        return self._tree_repr('    ', opening, closing, density=1)
456

Eckhart Arnold's avatar
Eckhart Arnold committed
457

Eckhart Arnold's avatar
Eckhart Arnold committed
458
459
460
    def structure(self) -> str:
        """Return structure (and content) as S-expression on a single line
        without any line breaks."""
Eckhart Arnold's avatar
Eckhart Arnold committed
461
462
        return flatten_sxpr(self.as_sxpr())

463

Eckhart Arnold's avatar
Eckhart Arnold committed
464
    def content(self) -> str:
465
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
466
467
        Returns content as string, inserting error messages where
        errors occurred.
468
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
469
470
        s = "".join(child.content() for child in self.children) if self.children \
            else str(self.result)
471
472
        return (' <<< Error on "%s" | %s >>> '
                % (s, '; '.join(e.message for e in self._errors))) if self._errors else s
473

Eckhart Arnold's avatar
Eckhart Arnold committed
474

475
    def find(self, match_function: Callable) -> Iterator['Node']:
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
        """Finds nodes in the tree that match a specific criterion.
        
        ``find`` is a generator that yields all nodes for which the
        given ``match_function`` evaluates to True. The tree is 
        traversed pre-order.
        
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
        Yields:
            Node: all nodes of the tree for which 
            ``match_function(node)`` returns True
        """
        if match_function(self):
            yield self
        else:
            for child in self.children:
                for nd in child.find(match_function):
                    yield nd

Eckhart Arnold's avatar
Eckhart Arnold committed
496

497
498
499
500
501
    def tree_size(self) -> int:
        """Recursively counts the number of nodes in the tree including the root node."""
        return sum(child.tree_size() for child in self.children) + 1


Eckhart Arnold's avatar
Eckhart Arnold committed
502
    def log(self, log_file_name):
503
        if is_logging():
Eckhart Arnold's avatar
Eckhart Arnold committed
504
505
506
507
            path = os.path.join(log_dir(), log_file_name)
            if os.path.exists(path):
                print('WARNING: Log-file "%s" already exists and will be overwritten!' % path)
            with open(path, "w", encoding="utf-8") as f:
508
                f.write(self.as_sxpr())
Eckhart Arnold's avatar
Eckhart Arnold committed
509

510

511
def mock_syntax_tree(sxpr):
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
    """
    Generates a tree of nodes from an S-expression.

    Example:
    >>> mock_syntax_tree("(a (b c))").as_sxpr()
    '(a\\n    (b\\n        "c"\\n    )\\n)'
    """

    def next_block(s):
        s = s.strip()
        while s[0] != ')':
            if s[0] != '(': raise ValueError('"(" expected, not ' + s[:10])
            # assert s[0] == '(', s
            level = 1
            i = 1
            while level > 0:
                if s[i] == '(':
                    level += 1
                elif s[i] == ')':
                    level -= 1
                i += 1
            yield s[:i]
            s = s[i:].strip()

536
537
538
539
540
541
542
543
544
    sxpr = sxpr.strip()
    if sxpr[0] != '(': raise ValueError('"(" expected, not ' + sxpr[:10])
    # assert sxpr[0] == '(', sxpr
    sxpr = sxpr[1:].strip()
    m = re.match('[\w:]+', sxpr)
    name, class_name = (sxpr[:m.end()].split(':') + [''])[:2]
    sxpr = sxpr[m.end():].strip()
    if sxpr[0] == '(':
        result = tuple(mock_syntax_tree(block) for block in next_block(sxpr))
545
546
    else:
        lines = []
547
        while sxpr and sxpr[0] != ')':
548
            for qm in ['"""', "'''", '"', "'"]:
549
                m = re.match(qm + r'.*?' + qm, sxpr, re.DOTALL)
550
551
                if m:
                    i = len(qm)
552
553
                    lines.append(sxpr[i:m.end() - i])
                    sxpr = sxpr[m.end():].strip()
554
555
                    break
            else:
556
557
558
                m = re.match(r'(?:(?!\)).)*', sxpr, re.DOTALL)
                lines.append(sxpr[:m.end()])
                sxpr = sxpr[m.end():]
559
560
561
562
        result = "\n".join(lines)
    return Node(MockParser(name, ':' + class_name), result)


563
TransformationFunc = Union[Callable[[Node], Any], partial]
564

565
566
567
568
569

# if __name__ == "__main__":
#     st = mock_syntax_tree("(alpha (beta (gamma i\nj\nk) (delta y)) (epsilon z))")
#     print(st.as_sxpr())
#     print(st.as_xml())