syntaxtree.py 23.7 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
from DHParser.error import Error, linebreaks, line_col
25
from DHParser.stringview import StringView
di68kap's avatar
di68kap committed
26 27 28
from DHParser.toolkit import is_logging, log_dir, identity, re, typing
from typing import Any, Callable, cast, Iterator, List, Union, Tuple, Hashable, Optional

29

30 31 32 33 34 35 36
__all__ = ('ParserBase',
           'WHITESPACE_PTYPE',
           'TOKEN_PTYPE',
           'MockParser',
           'ZombieParser',
           'ZOMBIE_PARSER',
           'Node',
37 38
           'mock_syntax_tree',
           'TransformationFunc')
Eckhart Arnold's avatar
Eckhart Arnold committed
39 40


41 42 43 44 45 46 47 48 49 50 51 52 53 54
#######################################################################
#
# 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()):
55
        self._name = name  # type: str
56 57 58 59 60 61 62 63
        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)

64 65 66
    def __call__(self, text: StringView) -> Tuple[Optional['Node'], StringView]:
        return None, text

67 68
    @property
    def name(self):
69 70
        """Returns the name of the parser or the empty string '' for unnamed
        parsers."""
71 72
        return self._name

73 74
    @property
    def ptype(self) -> str:
75 76
        """Returns the type of the parser. By default this is the parser's
        class name preceded by a colon, e.g. ':ZeroOrMore'."""
77 78 79 80
        return self._ptype

    @property
    def repr(self) -> str:
81 82
        """Returns the parser's name if it has a name and the parser's
        `ptype` otherwise. Note that for named parsers this is not the
eckhart's avatar
eckhart committed
83
        same as `repr(parsers)` which always returns the comined name
84
        and ptype, e.g. 'term:OneOrMore'."""
85 86
        return self.name if self.name else repr(self)

87
    def reset(self):
88
        """Resets any parser variables. (Should be overridden.)"""
89 90
        pass

eckhart's avatar
eckhart committed
91
    def grammar(self) -> Optional[object]:
92 93
        """Returns the Grammar object to which the parser belongs. If not
        yet connected to any Grammar object, None is returned."""
94 95 96
        return None

    def apply(self, func: Callable) -> bool:
eckhart's avatar
eckhart committed
97
        """Applies the function `func` to the parser. Returns False, if
98
        - for whatever reason - the functions has not been applied, True
eckhart's avatar
eckhart committed
99
        otherwise."""
100 101
        return False

102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118

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] == ':'
119
        super().__init__(name)
120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161
        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
#
#######################################################################


162
ChildrenType = Tuple['Node', ...]
Eckhart Arnold's avatar
Eckhart Arnold committed
163
NoChildren = cast(ChildrenType, ())  # type: ChildrenType
164
StrictResultType = Union[ChildrenType, str]
165
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
166 167


Eckhart Arnold's avatar
Eckhart Arnold committed
168 169
def flatten_sxpr(sxpr: str) -> str:
    """Returns S-expression `sxpr` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
170 171 172
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
173
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
174 175
    '(a (b c))'
    """
176
    return re.sub(r'\s(?=\))', '', re.sub(r'\s+', ' ', sxpr)).strip()
Eckhart Arnold's avatar
Eckhart Arnold committed
177 178


Eckhart Arnold's avatar
Eckhart Arnold committed
179
class Node(collections.abc.Sized):
180 181 182
    """
    Represents a node in the concrete or abstract syntax tree.

183
    Attributes and Properties:
184 185 186 187 188 189 190
        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!
Eckhart Arnold's avatar
Eckhart Arnold committed
191
        parser (Parser):  The parser which generated this node.
192 193
            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
194 195
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
196
            example by calling ``isinstance(node.parer, ...)``.
197 198
        errors (list):  A list of parser- or compiler-errors:
            tuple(position, string) attached to this node
199 200 201
        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.
202 203 204 205 206 207 208
        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.

Eckhart Arnold's avatar
Eckhart Arnold committed
209
            The value of ``pos`` is -1 meaning invalid by default.
210
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
211
            nodes relative to this value.
212 213

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
214
            pos value of the root node should be set to 0 right
215 216
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
217
            Other than that, this value should be considered READ ONLY.
218 219 220 221
            At any rate, it should only be reassigned only during
            parsing stage and never during or after the
            AST-transformation.
    """
222

223 224
    __slots__ = ['_result', 'children', '_errors', '_len', '_pos', 'parser', 'error_flag']

225

226 227 228
    def __init__(self, parser, result: ResultType, leafhint: bool = False) -> None:
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
229 230
        that generated the node and the parser's result.
        """
231 232
        self.error_flag = 0             # type: int
        self._errors = []               # type: List[Error]
di68kap's avatar
di68kap committed
233 234
        # 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
235
        if leafhint:
236
            self._result = str(result)  # type: StrictResultType
237
            self.children = NoChildren  # type: ChildrenType
238
            self._len = -1              # type: int  # lazy evaluation
239 240
        else:
            self.result = result
Eckhart Arnold's avatar
Eckhart Arnold committed
241
        # self.pos: int  = 0  # continuous updating of pos values wastes a lot of time
242
        self._pos = -1  # type: int
243 244
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
245

246
    def __str__(self):
247 248 249 250 251
        s = "".join(str(child) for child in self.children) if self.children else self.result
        if self._errors:
            return ' <<< Error on "%s" | %s >>> ' % \
                   (s, '; '.join(e.message for e in self._errors))
        return s
252

Eckhart Arnold's avatar
Eckhart Arnold committed
253

254 255 256 257 258 259
    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)
260

Eckhart Arnold's avatar
Eckhart Arnold committed
261

262
    def __len__(self):
263
        if self._len < 0:
di68kap's avatar
di68kap committed
264
            self._len = sum(len(child) for child in self.children) \
265
                if self.children else len(self._result)
266 267 268
        return self._len


269

270 271 272 273 274
    def __bool__(self):
        # A node that is not None is always True, even if it's empty
        return True


275
    def __eq__(self, other):
276 277
        # return str(self.parser) == str(other.parser) and self.result == other.result
        return self.tag_name == other.tag_name and self.result == other.result
278

Eckhart Arnold's avatar
Eckhart Arnold committed
279

280
    def __hash__(self):
281
        return hash(self.tag_name)
282

Eckhart Arnold's avatar
Eckhart Arnold committed
283

284 285 286 287 288 289
    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
290

291
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
292
    def tag_name(self) -> str:
293 294 295 296 297 298
        """
        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`.
        """
299
        return self.parser.name or self.parser.ptype
300

Eckhart Arnold's avatar
Eckhart Arnold committed
301

302
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
303
    def result(self) -> StrictResultType:
304 305 306 307 308
        """
        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.
        """
309 310
        return self._result

311

312
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
313
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
314
        # # made obsolete by static type checking with mypy
315 316 317
        # 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
318 319
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
320
        self._len = -1  # lazy evaluation
321 322 323 324 325 326 327 328
        if isinstance(result, Node):
            self.children = (result,)
            self._result = self.children
            self.error_flag = result.error_flag
        else:
            if isinstance(result, tuple):
                self.children = result
                self._result = result or ''
329 330 331
                if result:
                    if self.error_flag == 0:
                        self.error_flag = max(child.error_flag for child in self.children)
332 333
            else:
                self.children = NoChildren
334
                self._result = str(result)
335 336 337 338 339 340 341 342
        # # shorter but slower:
        # self._result = (result,) if isinstance(result, Node) else result or ''  # type: StrictResultType
        # self.children = cast(ChildrenType, self._result) \
        #     if isinstance(self._result, tuple) else NoChildren  # type: ChildrenType
        # if self.children:
        #     self.error_flag = max(self.error_flag,
        #                           max(child.error_flag for child in self.children))  # type: bool

343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363

    @property
    def content(self) -> str:
        """
        Returns content as string, inserting error messages where
        errors occurred.
        """
        if self.children:
            return "".join(child.content for child in self.children)
        return self._result


    @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))


364
    @property
365
    def pos(self) -> int:
eckhart's avatar
eckhart committed
366 367 368
        """Returns the position of the Node's content in the source text."""
        if self._pos < 0:
            raise AssertionError("position value not initialized!")
369 370 371
        return self._pos

    @pos.setter
372
    def pos(self, pos: int):
373 374
        self._pos = pos
        offset = 0
375
        # recursively adjust pos-values of all children
376 377
        for child in self.children:
            child.pos = pos + offset
378
            offset += len(child)
379 380 381
        # add pos-values to Error-objects
        for err in self._errors:
            err.pos = pos
382

Eckhart Arnold's avatar
Eckhart Arnold committed
383

384
    @property
385
    def errors(self) -> List[Error]:
eckhart's avatar
eckhart committed
386
        """
387
        Returns the errors that occurred at this Node,
eckhart's avatar
eckhart committed
388 389
        not including any errors from child nodes.
        """
390 391
        return self._errors.copy()

392

eckhart's avatar
eckhart committed
393 394
    def add_error(self,
                  message: str,
395
                  code: int = Error.ERROR) -> 'Node':
eckhart's avatar
eckhart committed
396 397 398
        """
        Adds an error to this Node.
        Parameters:
eckhart's avatar
eckhart committed
399 400
            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
401
        """
402 403
        self._errors.append(Error(message, code))
        self.error_flag = max(self.error_flag, self._errors[-1].code)
Eckhart Arnold's avatar
Eckhart Arnold committed
404 405
        return self

406

407 408
    def collect_errors(self, document: Union[StringView, str] = '', clear_errors=False) \
            -> List[Error]:
Eckhart Arnold's avatar
Eckhart Arnold committed
409
        """
410
        Recursively adds line- and column-numbers to all error objects.
Eckhart Arnold's avatar
Eckhart Arnold committed
411 412 413 414
        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.
        """
415 416 417 418 419 420
        if self.error_flag:
            lbreaks = linebreaks(document) if document else []
            return self._collect_errors(lbreaks, clear_errors)
        else:
            return []

eckhart's avatar
eckhart committed
421
    def _collect_errors(self, lbreaks: List[int] = [], clear_errors=False) -> List[Error]:
422 423 424 425 426 427 428 429 430 431 432
        errors = self.errors
        if errors and lbreaks:
            for err in errors:
                err.pos = self.pos
                err.line, err.column = line_col(lbreaks, err.pos)
        if self.children:
            for child in self.children:
                errors.extend(child._collect_errors(lbreaks, clear_errors))
        if clear_errors:
            self._errors = []
            self.error_flag = 0
433
        else:
434 435 436 437 438 439 440
            if self._errors:
                self.error_flag = max(err.code for err in self.errors)
            if self.children:
                max_child_error = max(child.error_flag for child in self.children)
                self.error_flag = max(self.error_flag, max_child_error)
        return errors

441

Eckhart Arnold's avatar
Eckhart Arnold committed
442

eckhart's avatar
eckhart committed
443
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=identity, density=0) -> str:
444 445 446 447 448 449 450 451
        """
        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.

452
        Args:
453
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
454
            open_fn:   (Node->str) A function that returns an opening
455
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
456
            close_fn:  (Node->str) A function that returns a closeF
457
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
458
            data_fn:   (str->str) A function that filters the data string
459 460 461 462 463 464
                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
465 466
        head = open_fn(self)
        tail = close_fn(self)
467 468

        if not self.result:
469
            return head.rstrip() + tail.lstrip()
470

eckhart's avatar
eckhart committed
471
        tail = tail.lstrip(None if density & 2 else '')
472 473 474

        if self.children:
            content = []
475
            for child in self.children:
eckhart's avatar
eckhart committed
476
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn, density).split('\n')
477
                content.append('\n'.join((tab + s) for s in subtree))
eckhart's avatar
eckhart committed
478
            return head + '\n'.join(content) + tail
479

480
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
481 482 483
        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
484
            return head.rstrip() + gap + data_fn(self.result) + tail.lstrip()
485
        else:
eckhart's avatar
eckhart committed
486
            return head + '\n'.join([tab + data_fn(s) for s in res.split('\n')]) + tail
487

Eckhart Arnold's avatar
Eckhart Arnold committed
488

489
    def as_sxpr(self, src: str = None, compact: bool = False, showerrors: bool = True) -> str:
490 491 492
        """
        Returns content as S-expression, i.e. in lisp-like form.

493
        Args:
494 495 496
            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
497 498 499
            compact:  If True a compact representation is returned where
                brackets are ommited and only the indentation indicates the
                tree structure.
500 501
        """

eckhart's avatar
eckhart committed
502
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
503

504
        def opening(node) -> str:
eckhart's avatar
eckhart committed
505 506
            """Returns the opening string for the representation of `node`."""
            txt = left_bracket + node.tag_name
507 508
            # s += " '(pos %i)" % node.pos
            if src:
eckhart's avatar
eckhart committed
509
                txt += " '(pos %i " % node.pos  # + " %i %i)" % line_col(src, node.pos)
di68kap's avatar
di68kap committed
510 511
            # if node.error_flag:   # just for debugging error collecting
            #     txt += " HAS ERRORS"
512
            if showerrors and node.errors:
eckhart's avatar
eckhart committed
513 514 515
                txt += " '(err '(%s))" % ' '.join(str(err).replace('"', r'\"')
                                                  for err in node.errors)
            return txt + '\n'
516

eckhart's avatar
eckhart committed
517 518 519
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
520

eckhart's avatar
eckhart committed
521 522 523 524 525
        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'\"')
526

eckhart's avatar
eckhart committed
527
        return self._tree_repr('    ', opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
528

eckhart's avatar
eckhart committed
529

530
    def as_xml(self, src: str = None, showerrors: bool = True) -> str:
531 532 533
        """
        Returns content as XML-tree.

534
        Args:
535 536 537 538 539
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
        """

540
        def opening(node) -> str:
eckhart's avatar
eckhart committed
541 542
            """Returns the opening string for the representation of `node`."""            
            txt = '<' + node.tag_name
543 544
            # s += ' pos="%i"' % node.pos
            if src:
eckhart's avatar
eckhart committed
545
                txt += ' line="%i" col="%i"' % line_col(src, node.pos)
546
            if showerrors and node.errors:
eckhart's avatar
eckhart committed
547 548
                txt += ' err="%s"' % ''.join(str(err).replace('"', r'\"') for err in node.errors)
            return txt + ">\n"
549 550

        def closing(node):
eckhart's avatar
eckhart committed
551
            """Returns the closing string for the representation of `node`."""            
552
            return '\n</' + node.tag_name + '>'
553

554
        return self._tree_repr('    ', opening, closing, density=1)
555

Eckhart Arnold's avatar
Eckhart Arnold committed
556

557
    def find(self, match_function: Callable) -> Iterator['Node']:
eckhart's avatar
eckhart committed
558 559 560
        """
        Finds nodes in the tree that match a specific criterion.

di68kap's avatar
di68kap committed
561 562
        `find` is a generator that yields all nodes for which the
        given `match_function` evaluates to True. The tree is
563
        traversed pre-order.
eckhart's avatar
eckhart committed
564

565 566 567 568
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
        Yields:
eckhart's avatar
eckhart committed
569
            Node: all nodes of the tree for which
570 571 572 573 574 575
            ``match_function(node)`` returns True
        """
        if match_function(self):
            yield self
        else:
            for child in self.children:
eckhart's avatar
eckhart committed
576 577
                for node in child.find(match_function):
                    yield node
578

Eckhart Arnold's avatar
Eckhart Arnold committed
579

580
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
581 582 583
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
584 585 586
        return sum(child.tree_size() for child in self.children) + 1


Eckhart Arnold's avatar
Eckhart Arnold committed
587
    def log(self, log_file_name):
eckhart's avatar
eckhart committed
588
        """
589
        Writes an S-expression-representation of the tree with root `self` to a file.
eckhart's avatar
eckhart committed
590
        """
591
        if is_logging():
Eckhart Arnold's avatar
Eckhart Arnold committed
592 593 594 595
            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:
596
                f.write(self.as_sxpr())
Eckhart Arnold's avatar
Eckhart Arnold committed
597

598

599
def mock_syntax_tree(sxpr):
600
    """
di68kap's avatar
di68kap committed
601 602
    Generates a tree of nodes from an S-expression. The main purpose of this is
    to generate test data.
603 604 605 606 607 608 609

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

    def next_block(s):
eckhart's avatar
eckhart committed
610 611 612
        """Generator that yields all characters until the next closing bracket
        that does not match an opening bracket matched earlier within the same
        package."""
613 614
        s = s.strip()
        while s[0] != ')':
eckhart's avatar
eckhart committed
615 616
            if s[0] != '(':
                raise ValueError('"(" expected, not ' + s[:10])
617 618
            # assert s[0] == '(', s
            level = 1
619
            k = 1
620
            while level > 0:
621
                if s[k] == '(':
622
                    level += 1
623
                elif s[k] == ')':
624
                    level -= 1
625 626 627
                k += 1
            yield s[:k]
            s = s[k:].strip()
628

629
    sxpr = sxpr.strip()
eckhart's avatar
eckhart committed
630 631
    if sxpr[0] != '(':
        raise ValueError('"(" expected, not ' + sxpr[:10])
632 633
    # assert sxpr[0] == '(', sxpr
    sxpr = sxpr[1:].strip()
eckhart's avatar
eckhart committed
634 635 636
    match = re.match(r'[\w:]+', sxpr)
    name, class_name = (sxpr[:match.end()].split(':') + [''])[:2]
    sxpr = sxpr[match.end():].strip()
637 638
    if sxpr[0] == '(':
        result = tuple(mock_syntax_tree(block) for block in next_block(sxpr))
639 640
    else:
        lines = []
641
        while sxpr and sxpr[0] != ')':
eckhart's avatar
eckhart committed
642 643 644 645 646 647
            for qtmark in ['"""', "'''", '"', "'"]:
                match = re.match(qtmark + r'.*?' + qtmark, sxpr, re.DOTALL)
                if match:
                    i = len(qtmark)
                    lines.append(sxpr[i:match.end() - i])
                    sxpr = sxpr[match.end():].strip()
648 649
                    break
            else:
eckhart's avatar
eckhart committed
650 651 652
                match = re.match(r'(?:(?!\)).)*', sxpr, re.DOTALL)
                lines.append(sxpr[:match.end()])
                sxpr = sxpr[match.end():]
653 654 655 656
        result = "\n".join(lines)
    return Node(MockParser(name, ':' + class_name), result)


657
TransformationFunc = Union[Callable[[Node], Any], partial]
658

659 660 661 662 663

# 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())