In January 2021 we will introduce a 10 GB quota for project repositories. Higher limits for individual projects will be available on request. Please see https://doku.lrz.de/display/PUBLIC/GitLab for more information.

syntaxtree.py 27.3 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
import copy
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
33
from typing import Callable, cast, Iterator, List, Union, Tuple, Optional
di68kap's avatar
di68kap committed
34

35

36 37 38 39 40 41 42
__all__ = ('ParserBase',
           'WHITESPACE_PTYPE',
           'TOKEN_PTYPE',
           'MockParser',
           'ZombieParser',
           'ZOMBIE_PARSER',
           'Node',
43
           'mock_syntax_tree',
44
           'flatten_sxpr')
Eckhart Arnold's avatar
Eckhart Arnold committed
45 46


47 48 49 50 51 52 53 54 55 56 57 58 59 60
#######################################################################
#
# 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()):
61
        self._name = name  # type: str
62 63 64
        self._ptype = ':' + self.__class__.__name__  # type: str

    def __repr__(self):
di68kap's avatar
di68kap committed
65
         return self.name + self.ptype
66 67 68 69

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

70 71 72
    def __call__(self, text: StringView) -> Tuple[Optional['Node'], StringView]:
        return None, text

73 74
    @property
    def name(self):
75 76
        """Returns the name of the parser or the empty string '' for unnamed
        parsers."""
77 78
        return self._name

79 80
    @property
    def ptype(self) -> str:
81 82
        """Returns the type of the parser. By default this is the parser's
        class name preceded by a colon, e.g. ':ZeroOrMore'."""
83 84 85 86
        return self._ptype

    @property
    def repr(self) -> str:
di68kap's avatar
di68kap committed
87
        """Returns the parser's name if it has a name and repr()"""
88 89
        return self.name if self.name else repr(self)

90
    def reset(self):
91
        """Resets any parser variables. (Should be overridden.)"""
92 93
        pass

eckhart's avatar
eckhart committed
94
    def grammar(self) -> Optional[object]:
95 96
        """Returns the Grammar object to which the parser belongs. If not
        yet connected to any Grammar object, None is returned."""
97 98 99
        return None

    def apply(self, func: Callable) -> bool:
eckhart's avatar
eckhart committed
100
        """Applies the function `func` to the parser. Returns False, if
101
        - for whatever reason - the functions has not been applied, True
eckhart's avatar
eckhart committed
102
        otherwise."""
103 104
        return False

105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121

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] == ':'
122
        super().__init__(name)
123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
        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
#
#######################################################################


165
ChildrenType = Tuple['Node', ...]
Eckhart Arnold's avatar
Eckhart Arnold committed
166
NoChildren = cast(ChildrenType, ())  # type: ChildrenType
eckhart's avatar
eckhart committed
167
StrictResultType = Union[ChildrenType, StringView, str]
168
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
169 170


Eckhart Arnold's avatar
Eckhart Arnold committed
171
def flatten_sxpr(sxpr: str) -> str:
172
    """Returns S-expression ``sxpr`` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
173 174 175
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
176
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
177 178
    '(a (b c))'
    """
179
    return re.sub(r'\s(?=\))', '', re.sub(r'\s+', ' ', sxpr)).strip()
Eckhart Arnold's avatar
Eckhart Arnold committed
180 181


Eckhart Arnold's avatar
Eckhart Arnold committed
182
class Node(collections.abc.Sized):
183 184 185
    """
    Represents a node in the concrete or abstract syntax tree.

186
    Attributes:
187 188
        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
189

190 191 192
        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.
193

194 195
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
196

eckhart's avatar
eckhart committed
197 198 199 200
        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
201
        parser (Parser):  The parser which generated this node.
202 203
            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
204 205
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
206
            example by calling ``isinstance(node.parer, ...)``.
207

208 209
        errors (list):  A list of parser- or compiler-errors:
            tuple(position, string) attached to this node
210

211 212 213
        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.
214

215 216 217
        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
218
            the length before AST-transformation and will never change
219
            through AST-transformation. READ ONLY!
220

221 222
        pos (int):  the position of the node within the parsed text.

Eckhart Arnold's avatar
Eckhart Arnold committed
223
            The value of ``pos`` is -1 meaning invalid by default.
224
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
225
            nodes relative to this value.
226 227

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
228
            pos value of the root node should be set to 0 right
229 230
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
231
            Other than that, this value should be considered READ ONLY.
232 233
            At any rate, it should only be reassigned during the parsing
            stage and never during or after the AST-transformation.
234 235 236 237 238

        xml_attr (dict): An optional dictionary of XML-attributes. This
            dictionary is created lazily upon first usage. The attributes
            will only be shown in the XML-Representation, not in the
            S-Expression-output.
eckhart's avatar
eckhart committed
239 240 241


        _parent (Node): SLOT RESERVED FOR FUTURE USE!
242
    """
243

di68kap's avatar
di68kap committed
244
    __slots__ = ['_result', 'children', '_errors', '_len', '_pos', 'parser', 'error_flag',
eckhart's avatar
eckhart committed
245
                 '_xml_attr', '_parent']
246

247 248 249
    def __init__(self, parser, result: ResultType, leafhint: bool = False) -> None:
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
250 251
        that generated the node and the parser's result.
        """
252 253
        self.error_flag = 0             # type: int
        self._errors = []               # type: List[Error]
eckhart's avatar
eckhart committed
254
        self._pos = -1                  # type: int
di68kap's avatar
di68kap committed
255 256
        # 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
257
        if leafhint:
eckhart's avatar
eckhart committed
258
            self._result = result       # type: StrictResultType
259
            self.children = NoChildren  # type: ChildrenType
260
            self._len = -1              # type: int  # lazy evaluation
261 262
        else:
            self.result = result
263 264
        self.parser = parser or ZOMBIE_PARSER

Eckhart Arnold's avatar
Eckhart Arnold committed
265

266
    def __str__(self):
267 268 269 270 271
        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
272

Eckhart Arnold's avatar
Eckhart Arnold committed
273

274 275 276 277 278 279
    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)
280

Eckhart Arnold's avatar
Eckhart Arnold committed
281

282
    def __len__(self):
283
        if self._len < 0:
di68kap's avatar
di68kap committed
284
            self._len = sum(len(child) for child in self.children) \
285
                if self.children else len(self._result)
286 287 288 289 290 291 292 293
        return self._len


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


294
    def __eq__(self, other):
295 296 297 298
        """
        Equality of nodes: Two nodes are considered as equal, if their tag
        name is the same and if their results are equal.
        """
299
        return self.tag_name == other.tag_name and self.result == other.result
300

Eckhart Arnold's avatar
Eckhart Arnold committed
301

302
    def __hash__(self):
303
        return hash(self.tag_name)
304

Eckhart Arnold's avatar
Eckhart Arnold committed
305

306 307 308 309 310 311
    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
312

313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338
    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
        an integer value or a generator that yields all descendant nodes that
        match a particular tag name. Examples::

            >>> tree =  mock_syntax_tree('(a (b "X") (X (c "d")) (e (X "F")))')
            >>> flatten_sxpr(tree[0].as_sxpr())
            '(b "X")'
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree["X"])
            ['(X (c "d"))', '(X "F")']

        Args:
            index_or_tagname(str): Either an index of a child node or a
                tag name.
        Return:
            Node: All nodes which have a given tag name.
        """
        if isinstance(index_or_tagname, int):
            children = self.children
            if children:
                return children[index_or_tagname]
            else:
                raise ValueError('Leave nodes have no children that can be indexed!')
        else:
            match_function = lambda node: node.tag_name == index_or_tagname
339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357
            return self.find(match_function, False)


    def __contains__(self, tag_name: str) -> bool:
        """
        Returns true if a descendant with the given tag name exists.
        Args:
            tag_name: tag_name which will be searched among the descendant
                nodes
        Returns:
            bool:  True, if at least one descendant node with the given tag
                name exists, False otherwise
        """
        generator = self[tag_name]
        try:
            generator.__next__()
            return True
        except StopIteration:
            return False
358 359


360
    @property   # this needs to be a (dynamic) property, in case sef.parser gets updated
361
    def tag_name(self) -> str:
362 363 364 365 366 367
        """
        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`.
        """
368
        return self.parser.name or self.parser.ptype
369

Eckhart Arnold's avatar
Eckhart Arnold committed
370

371
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
372
    def result(self) -> StrictResultType:
373 374 375 376 377
        """
        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.
        """
378 379
        return self._result

380

381
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
382
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
383
        # # made obsolete by static type checking with mypy
384 385 386
        # 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
387 388
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
389
        self._len = -1  # lazy evaluation
390 391 392 393
        if isinstance(result, Node):
            self.children = (result,)
            self._result = self.children
            self.error_flag = result.error_flag
394 395
            # if self._pos < 0:
            #     self._pos = result._pos
396 397 398 399
        else:
            if isinstance(result, tuple):
                self.children = result
                self._result = result or ''
400 401 402
                if result:
                    if self.error_flag == 0:
                        self.error_flag = max(child.error_flag for child in self.children)
403 404
                    # if self._pos < 0:
                    #     self._pos = result[0]._pos
405 406
            else:
                self.children = NoChildren
407
                self._result = str(result)
408 409 410 411 412 413 414 415
        # # 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

416 417 418 419

    @property
    def content(self) -> str:
        """
420
        Returns content as string, omitting error messages.
421 422 423
        """
        if self.children:
            return "".join(child.content for child in self.children)
eckhart's avatar
eckhart committed
424
        return cast(str, self._result)
425 426 427 428 429 430 431 432 433 434 435


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


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

eckhart's avatar
eckhart committed
443

eckhart's avatar
eckhart committed
444
    def init_pos(self, pos: int, overwrite: bool = False) -> 'Node':
eckhart's avatar
eckhart committed
445 446 447 448 449 450 451 452 453
        """
        (Re-)initialize position value. Usually, the parser guard
        (`parsers.add_parser_guard()`) takes care of assigning the
        position in the document to newly created nodes. However,
        where Nodes are created outside the reach of the parser
        guard, their document-position must be assigned manually.
        This function recursively reassigns the position values
        of the child nodes, too.
        """
eckhart's avatar
eckhart committed
454 455 456 457 458 459
        if overwrite or self._pos < 0:
            self._pos = pos
            for err in self._errors:
                err.pos = pos
        else:
            assert self._pos == pos, str("%i != %i" % (self._pos, pos))
460
        # recursively adjust pos-values of all children
eckhart's avatar
eckhart committed
461
        offset = self.pos
462
        for child in self.children:
eckhart's avatar
eckhart committed
463
            child.init_pos(offset, overwrite)
eckhart's avatar
eckhart committed
464 465 466
            offset = child.pos + len(child)
        return self

467 468

    @property
469
    def errors(self) -> List[Error]:
eckhart's avatar
eckhart committed
470
        """
471
        Returns the errors that occurred at this Node,
eckhart's avatar
eckhart committed
472 473
        not including any errors from child nodes.
        """
474 475
        return self._errors.copy()

476

eckhart's avatar
eckhart committed
477 478
    def add_error(self,
                  message: str,
479
                  code: int = Error.ERROR) -> 'Node':
eckhart's avatar
eckhart committed
480 481 482
        """
        Adds an error to this Node.
        Parameters:
eckhart's avatar
eckhart committed
483 484
            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
485
        """
486 487
        self._errors.append(Error(message, code))
        self.error_flag = max(self.error_flag, self._errors[-1].code)
Eckhart Arnold's avatar
Eckhart Arnold committed
488 489
        return self

490

491
    def collect_errors(self, clear_errors=False) -> List[Error]:
Eckhart Arnold's avatar
Eckhart Arnold committed
492
        """
493
        Recursively adds line- and column-numbers to all error objects.
Eckhart Arnold's avatar
Eckhart Arnold committed
494 495 496 497
        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.
        """
498
        errors = self.errors
499 500
        for err in errors:
            err.pos = self.pos
501 502
        if self.children:
            for child in self.children:
503
                errors.extend(child.collect_errors(clear_errors))
504 505 506
        if clear_errors:
            self._errors = []
            self.error_flag = 0
507
        else:
508 509 510 511 512 513 514
            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

515

Eckhart Arnold's avatar
Eckhart Arnold committed
516

517
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=lambda i: i, density=0) -> str:
518 519 520 521 522 523 524 525
        """
        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.

526
        Args:
527
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
528
            open_fn:   (Node->str) A function that returns an opening
529
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
530
            close_fn:  (Node->str) A function that returns a closeF
531
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
532
            data_fn:   (str->str) A function that filters the data string
533 534 535 536 537 538
                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
539 540
        head = open_fn(self)
        tail = close_fn(self)
541 542

        if not self.result:
543
            return head.rstrip() + tail.lstrip()
544

eckhart's avatar
eckhart committed
545
        tail = tail.lstrip(None if density & 2 else '')
546 547 548

        if self.children:
            content = []
549
            for child in self.children:
eckhart's avatar
eckhart committed
550
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn, density).split('\n')
551
                content.append('\n'.join((tab + s) for s in subtree))
eckhart's avatar
eckhart committed
552
            return head + '\n'.join(content) + tail
553

554
        res = cast(str, self.result)  # safe, because if there are no children, result is a string
555 556 557
        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
558
            return head.rstrip() + gap + data_fn(self.result) + tail.lstrip()
559
        else:
eckhart's avatar
eckhart committed
560
            return head + '\n'.join([tab + data_fn(s) for s in res.split('\n')]) + tail
561

Eckhart Arnold's avatar
Eckhart Arnold committed
562

563
    def as_sxpr(self, src: str = None, compact: bool = False, showerrors: bool = True) -> str:
564 565 566
        """
        Returns content as S-expression, i.e. in lisp-like form.

567
        Args:
568 569 570
            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
571
            compact:  If True a compact representation is returned where
572
                brackets are omitted and only the indentation indicates the
Eckhart Arnold's avatar
Eckhart Arnold committed
573
                tree structure.
574 575
        """

eckhart's avatar
eckhart committed
576
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
577

578
        def opening(node) -> str:
eckhart's avatar
eckhart committed
579 580
            """Returns the opening string for the representation of `node`."""
            txt = left_bracket + node.tag_name
581 582
            # s += " '(pos %i)" % node.pos
            if src:
eckhart's avatar
eckhart committed
583
                txt += " '(pos %i " % node.pos  # + " %i %i)" % line_col(src, node.pos)
di68kap's avatar
di68kap committed
584 585
            # if node.error_flag:   # just for debugging error collecting
            #     txt += " HAS ERRORS"
586
            if showerrors and node.errors:
eckhart's avatar
eckhart committed
587 588 589
                txt += " '(err '(%s))" % ' '.join(str(err).replace('"', r'\"')
                                                  for err in node.errors)
            return txt + '\n'
590

eckhart's avatar
eckhart committed
591 592 593
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
594

eckhart's avatar
eckhart committed
595 596 597 598 599
        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'\"')
600

eckhart's avatar
eckhart committed
601
        return self._tree_repr('    ', opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
602

eckhart's avatar
eckhart committed
603

eckhart's avatar
eckhart committed
604 605 606 607 608 609 610 611
    @property
    def xml_attr(self):
        """Returns a dictionary of XML-Attributes attached to the Node."""
        if not hasattr(self, '_xml_attr'):
            self._xml_attr = dict()
        return self._xml_attr


612
    def as_xml(self, src: str = None, showerrors: bool = True) -> str:
613 614 615
        """
        Returns content as XML-tree.

616
        Args:
617 618 619 620 621
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
        """

622
        def opening(node) -> str:
eckhart's avatar
eckhart committed
623
            """Returns the opening string for the representation of `node`."""            
eckhart's avatar
eckhart committed
624
            txt = ['<', node.tag_name]
625
            # s += ' pos="%i"' % node.pos
di68kap's avatar
di68kap committed
626 627
            if hasattr(node, '_xml_attr'):
                txt.extend(' %s="%s"' % (k, v) for k, v in node.xml_attr.items())
628
            if src:
eckhart's avatar
eckhart committed
629
                txt.append(' line="%i" col="%i"' % line_col(line_breaks, node.pos))
630
            if showerrors and node.errors:
eckhart's avatar
eckhart committed
631 632 633
                txt.append(' err="%s"' % ''.join(str(err).replace('"', r'\"')
                                                 for err in node.errors))
            return "".join(txt + [">\n"])
634 635

        def closing(node):
eckhart's avatar
eckhart committed
636
            """Returns the closing string for the representation of `node`."""            
637
            return '\n</' + node.tag_name + '>'
638

639
        line_breaks = linebreaks(src) if src else []
640
        return self._tree_repr('    ', opening, closing, density=1)
641

Eckhart Arnold's avatar
Eckhart Arnold committed
642

643
    def find(self, match_function: Callable, include_root: bool=True) -> Iterator['Node']:
eckhart's avatar
eckhart committed
644
        """
645
        Finds nodes in the tree that fulfill a given criterion.
eckhart's avatar
eckhart committed
646

di68kap's avatar
di68kap committed
647 648
        `find` is a generator that yields all nodes for which the
        given `match_function` evaluates to True. The tree is
649
        traversed pre-order.
eckhart's avatar
eckhart committed
650

651 652 653
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
654 655
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
656
        Yields:
657
            Node: All nodes of the tree for which
658 659
            ``match_function(node)`` returns True
        """
660
        if include_root and match_function(self):
661 662 663
            yield self
        else:
            for child in self.children:
664
                for node in child.find(match_function, True):
eckhart's avatar
eckhart committed
665
                    yield node
666

Eckhart Arnold's avatar
Eckhart Arnold committed
667

668 669 670 671 672 673 674 675 676 677 678
    def find_by_tag(self, tag_name: str) -> Iterator['Node']:
        """
        Finds all nodes with the given tag name.

        Args:
            tag_name(str): The tag name that is being searched for.
        Yields:
            Node: All nodes which have a given tag name.
        """


679
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
680 681 682
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
683 684 685
        return sum(child.tree_size() for child in self.children) + 1


686
def mock_syntax_tree(sxpr):
687
    """
di68kap's avatar
di68kap committed
688 689
    Generates a tree of nodes from an S-expression. The main purpose of this is
    to generate test data.
690 691 692 693 694 695 696

    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
697 698 699
        """Generator that yields all characters until the next closing bracket
        that does not match an opening bracket matched earlier within the same
        package."""
700
        s = s.strip()
701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719
        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)
720

721
    sxpr = sxpr.strip()
eckhart's avatar
eckhart committed
722 723
    if sxpr[0] != '(':
        raise ValueError('"(" expected, not ' + sxpr[:10])
724 725
    # assert sxpr[0] == '(', sxpr
    sxpr = sxpr[1:].strip()
eckhart's avatar
eckhart committed
726
    match = re.match(r'[\w:]+', sxpr)
727 728 729
    if match is None:
        raise AssertionError('Malformed S-expression Node-tagname or identifier expected, '
                             'not "%s"' % sxpr[:40].replace('\n', ''))
eckhart's avatar
eckhart committed
730 731
    name, class_name = (sxpr[:match.end()].split(':') + [''])[:2]
    sxpr = sxpr[match.end():].strip()
732 733
    if sxpr[0] == '(':
        result = tuple(mock_syntax_tree(block) for block in next_block(sxpr))
734 735 736 737
        pos = 0
        for node in result:
            node._pos = pos
            pos += len(node)
738 739
    else:
        lines = []
740
        while sxpr and sxpr[0] != ')':
eckhart's avatar
eckhart committed
741 742 743 744 745 746
            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()
747 748
                    break
            else:
eckhart's avatar
eckhart committed
749 750 751
                match = re.match(r'(?:(?!\)).)*', sxpr, re.DOTALL)
                lines.append(sxpr[:match.end()])
                sxpr = sxpr[match.end():]
752
        result = "\n".join(lines)
753 754 755
    node = Node(MockParser(name, ':' + class_name), result)
    node._pos = 0
    return node
756

757 758 759 760
# 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())