syntaxtree.py 43.5 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
from collections import OrderedDict
eckhart's avatar
eckhart committed
27
import copy
28

eckhart's avatar
eckhart committed
29
from DHParser.error import Error, ErrorCode, linebreaks, line_col
30
from DHParser.stringview import StringView
di68kap's avatar
di68kap committed
31 32
from DHParser.toolkit import re
from typing import Callable, cast, Iterator, List, AbstractSet, Set, Union, Tuple, Optional
di68kap's avatar
di68kap committed
33

34

di68kap's avatar
di68kap committed
35
__all__ = ('WHITESPACE_PTYPE',
36
           'TOKEN_PTYPE',
37 38
           'ZOMBIE_TAG',
           'PLACEHOLDER',
eckhart's avatar
eckhart committed
39 40 41
           'ResultType',
           'StrictResultType',
           'ChildrenType',
42
           'Node',
43
           'FrozenNode',
44
           'tree_sanity_check',
di68kap's avatar
di68kap committed
45
           'RootNode',
46
           'parse_sxpr',
47
           'parse_xml',
eckhart's avatar
eckhart committed
48
           'parse_tree',
49 50
           'flatten_sxpr',
           'flatten_xml')
Eckhart Arnold's avatar
Eckhart Arnold committed
51 52


53 54 55 56 57 58 59 60
#######################################################################
#
# parser base and mock parsers
#
#######################################################################


WHITESPACE_PTYPE = ':Whitespace'
61
TOKEN_PTYPE = ':Token'
62

63
ZOMBIE_TAG = "__ZOMBIE__"
64

65 66 67 68 69 70 71
#######################################################################
#
# syntaxtree nodes
#
#######################################################################


72
ChildrenType = Tuple['Node', ...]
Eckhart Arnold's avatar
Eckhart Arnold committed
73
NoChildren = cast(ChildrenType, ())  # type: ChildrenType
eckhart's avatar
eckhart committed
74
StrictResultType = Union[ChildrenType, StringView, str]
75
ResultType = Union[ChildrenType, 'Node', StringView, str, None]
76 77


Eckhart Arnold's avatar
Eckhart Arnold committed
78
def flatten_sxpr(sxpr: str) -> str:
79 80
    """
    Returns S-expression ``sxpr`` as a one-liner without unnecessary
Eckhart Arnold's avatar
Eckhart Arnold committed
81 82 83
    whitespace.

    Example:
Eckhart Arnold's avatar
Eckhart Arnold committed
84
    >>> flatten_sxpr('(a\\n    (b\\n        c\\n    )\\n)\\n')
Eckhart Arnold's avatar
Eckhart Arnold committed
85 86
    '(a (b c))'
    """
87

88
    return re.sub(r'\s(?=\))', '', re.sub(r'\s+', ' ', sxpr)).strip()
Eckhart Arnold's avatar
Eckhart Arnold committed
89 90


91
def flatten_xml(xml: str) -> str:
92 93
    """
    Returns an XML-tree as a one liner without unnecessary whitespace,
94
    i.e. only whitespace within leaf-nodes is preserved.
95 96
    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`.
97
    """
98

99 100 101 102
    # 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']
103
    return re.sub(r'\s+(?=<[\w:])', '', re.sub(r'(?P<closing_tag></:?\w+>)\s+', tag_only, xml))
104 105


eckhart's avatar
eckhart committed
106
RX_AMP = re.compile(r'&(?!\w+;)')
107 108


Eckhart Arnold's avatar
Eckhart Arnold committed
109
class Node:  # (collections.abc.Sized): Base class omitted for cython-compatibility
110 111 112
    """
    Represents a node in the concrete or abstract syntax tree.

113 114
    TODO: Add some documentation and doc-tests here...

115
    Attributes:
116 117
        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
118

119 120 121
        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.
122

123 124
        children (tuple):  The tuple of child nodes or an empty tuple
            if there are no child nodes. READ ONLY!
125

eckhart's avatar
eckhart committed
126 127 128 129
        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
130
        parser (Parser):  The parser which generated this node.
131 132
            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
133 134
            rely on this being a real parser object in any phase after
            parsing (i.e. AST-transformation and compiling), for
135
            example by calling ``isinstance(node.parer, ...)``.
136

137 138 139
        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
140
            the length before AST-transformation and will never change
141
            through AST-transformation. READ ONLY!
142

143 144
        pos (int):  the position of the node within the parsed text.

Eckhart Arnold's avatar
Eckhart Arnold committed
145
            The value of ``pos`` is -1 meaning invalid by default.
146
            Setting this value will set the positions of all child
Eckhart Arnold's avatar
Eckhart Arnold committed
147
            nodes relative to this value.
148 149

            To set the pos values of all nodes in a syntax tree, the
Eckhart Arnold's avatar
Eckhart Arnold committed
150
            pos value of the root node should be set to 0 right
151 152
            after parsing.

Eckhart Arnold's avatar
Eckhart Arnold committed
153
            Other than that, this value should be considered READ ONLY.
154 155
            At any rate, it should only be reassigned during the parsing
            stage and never during or after the AST-transformation.
156

157 158
        attr (dict): An optional dictionary of XML-attr. This
            dictionary is created lazily upon first usage. The attr
159 160
            will only be shown in the XML-Representation, not in the
            S-Expression-output.
161
    """
162

163
    __slots__ = '_result', 'children', '_len', '_pos', 'tag_name', '_xml_attr', '_content'
164

165
    def __init__(self, tag_name: str, result: ResultType, leafhint: bool = False) -> None:
166 167
        """
        Initializes the ``Node``-object with the ``Parser``-Instance
168 169
        that generated the node and the parser's result.
        """
eckhart's avatar
eckhart committed
170
        self._pos = -1                  # type: int
171
        # Assignment to self.result initializes the attr _result, children and _len
di68kap's avatar
di68kap committed
172
        # The following if-clause is merely an optimization, i.e. a fast-path for leaf-Nodes
173
        if leafhint:
eckhart's avatar
eckhart committed
174
            self._result = result       # type: StrictResultType  # cast(StrictResultType, result)
eckhart's avatar
eckhart committed
175
            self._content = None        # type: Optional[str]
176
            self.children = NoChildren  # type: ChildrenType
177
            self._len = -1              # type: int  # lazy evaluation
178 179
        else:
            self.result = result
180
        self.tag_name = tag_name        # type: str
181

eckhart's avatar
eckhart committed
182 183
    def __deepcopy__(self, memo):
        if self.children:
184
            duplicate = self.__class__(self.tag_name, copy.deepcopy(self.children), False)
eckhart's avatar
eckhart committed
185
        else:
186
            duplicate = self.__class__(self.tag_name, self.result, True)
eckhart's avatar
eckhart committed
187 188
        duplicate._pos = self._pos
        duplicate._len = self._len
eckhart's avatar
eckhart committed
189
        if self.attr_active():
di68kap's avatar
di68kap committed
190 191
            duplicate.attr.update(copy.deepcopy(self._xml_attr))
            # duplicate._xml_attr = copy.deepcopy(self._xml_attr)  # this is not cython compatible
eckhart's avatar
eckhart committed
192
        return duplicate
Eckhart Arnold's avatar
Eckhart Arnold committed
193

194
    def __str__(self):
195 196
        if isinstance(self, RootNode):
            root = cast(RootNode, self)
197
            errors = root.errors_sorted
198 199 200 201 202 203
            if errors:
                e_pos = errors[0].pos
                return self.content[:e_pos] + \
                   ' <<< Error on "%s" | %s >>> ' % \
                   (self.content[e_pos - self.pos:], '; '.join(e.message for e in errors))
        return self.content
Eckhart Arnold's avatar
Eckhart Arnold committed
204

205
    def __repr__(self):
206
        # mpargs = {'name': self.parser.name, 'ptype': self.parser.ptype}
207 208
        # name, ptype = (self._tag_name.split(':') + [''])[:2]
        # parg = "MockParser({name}, {ptype})".format(name=name, ptype=ptype)
209
        rarg = str(self) if not self.children else \
210
            "(" + ", ".join(child.__repr__() for child in self.children) + ")"
211
        return "Node(%s, %s)" % (self.tag_name, rarg)
212

Eckhart Arnold's avatar
Eckhart Arnold committed
213

214
    def __len__(self):
215
        if self._len < 0:
di68kap's avatar
di68kap committed
216
            self._len = sum(len(child) for child in self.children) \
217
                if self.children else len(self._result)
218 219 220 221 222 223 224 225
        return self._len


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


226 227 228 229 230 231 232 233 234
    # can lead to obscure mistakes, where default object comparison behaviour is expected
    # def __eq__(self, other):
    #     """
    #     Equality of nodes: Two nodes are considered as equal, if their tag
    #     name is the same, if their results are equal and if their attributes
    #     and attribute values are the same.
    #     """
    #     return self.tag_name == other.tag_name and self.result == other.result \
    #         and self.compare_attr(other)
235

Eckhart Arnold's avatar
Eckhart Arnold committed
236

237
    def __hash__(self):
238
        return hash(self.tag_name)
239

Eckhart Arnold's avatar
Eckhart Arnold committed
240

241 242 243
    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
244
        an integer or the first child node with the given tag name. Examples::
245

246
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
247 248
            >>> flatten_sxpr(tree[0].as_sxpr())
            '(b "X")'
249 250
            >>> flatten_sxpr(tree["X"].as_sxpr())
            '(X (c "d"))'
251 252 253 254

        Args:
            index_or_tagname(str): Either an index of a child node or a
                tag name.
255
        Returns:
256 257
            Node: All nodes which have a given tag name.
        """
258 259 260
        if self.children:
            if isinstance(index_or_tagname, int):
                return self.children[index_or_tagname]
261
            else:
262 263 264 265 266
                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!')
267 268 269 270


    def __contains__(self, tag_name: str) -> bool:
        """
271
        Returns true if a child with the given tag name exists.
272
        Args:
273 274
            tag_name (str): tag_name which will be searched among to immediate
                descendants of this node.
275 276 277 278
        Returns:
            bool:  True, if at least one descendant node with the given tag
                name exists, False otherwise
        """
279 280 281 282 283
        # assert isinstance(tag_name, str)
        if self.children:
            for child in self.children:
                if child.tag_name == tag_name:
                    return True
284
            return False
285
        raise ValueError('Leave node cannot contain other nodes')
286 287


288 289 290 291 292 293 294 295 296 297 298 299 300 301 302
    def equals(self, other):
        """
        Equality of nodes: Two nodes are considered as equal, if their tag
        name is the same, if their results are equal and if their attributes
        and attribute values are the same.
        """
        if self.tag_name == other.tag_name and self.compare_attr(other):
            if self.children:
                return (len(self.children) == len(other.children)
                        and all(a.equals(b) for a, b in zip(self.children, other.children)))
            else:
                return self.result == other.result
        return False


303 304 305 306 307 308 309 310 311 312 313 314 315 316
    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


317
    def is_anonymous(self):
Eckhart Arnold's avatar
Eckhart Arnold committed
318
        return not self.tag_name or self.tag_name[0] == ':'
319

Eckhart Arnold's avatar
Eckhart Arnold committed
320

321
    @property
Eckhart Arnold's avatar
Eckhart Arnold committed
322
    def result(self) -> StrictResultType:
323 324 325 326 327
        """
        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.
        """
328 329
        return self._result

330

331
    @result.setter
Eckhart Arnold's avatar
Eckhart Arnold committed
332
    def result(self, result: ResultType):
Eckhart Arnold's avatar
Eckhart Arnold committed
333
        # # made obsolete by static type checking with mypy
Eckhart Arnold's avatar
Eckhart Arnold committed
334 335 336 337
        assert ((isinstance(result, tuple) and all(isinstance(child, Node) for child in result))
                or isinstance(result, Node)
                or isinstance(result, str)
                or isinstance(result, StringView)), "%s (%s)" % (str(result), str(type(result)))
Eckhart Arnold's avatar
Eckhart Arnold committed
338 339
        # Possible optimization: Do not allow single nodes as argument:
        # assert not isinstance(result, Node)
340 341
        self._len = -1        # lazy evaluation
        self._content = None
342 343 344 345 346 347 348 349 350
        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
eckhart's avatar
eckhart committed
351
                self._result = result  # cast(StrictResultType, result)
352

353 354

    @property
eckhart's avatar
eckhart committed
355
    def content(self) -> str:
356
        """
357 358 359
        Returns content as string. If the node has child-nodes, the
        string content of the child-nodes is recursively read and then
        concatenated.
360
        """
361 362 363 364
        if self._content is None:
            if self.children:
                self._content = "".join(child.content for child in self.children)
            else:
365
                # self._content = self._result
366 367 368
                self._content = str(self._result)
                self._result = self._content  # self._result might be more efficient as a string!?
        return self._content
369 370 371 372 373
    #
    #
    # @content.setter
    # def content(self, content: str):
    #     self.result = content
di68kap's avatar
di68kap committed
374 375


376 377 378 379 380 381
    @property
    def structure(self) -> str:
        """
        Return structure (and content) as S-expression on a single line
        without any line breaks.
        """
382
        return flatten_sxpr(self.as_sxpr())
383 384


385
    @property
386
    def pos(self) -> int:
eckhart's avatar
eckhart committed
387 388
        """Returns the position of the Node's content in the source text."""
        if self._pos < 0:
Eckhart Arnold's avatar
Eckhart Arnold committed
389
            raise AssertionError("Position value not initialized! Use Node.with_pos()")
390 391
        return self._pos

eckhart's avatar
eckhart committed
392

Eckhart Arnold's avatar
Eckhart Arnold committed
393
    def with_pos(self, pos: int) -> 'Node':
eckhart's avatar
eckhart committed
394
        """
Eckhart Arnold's avatar
Eckhart Arnold committed
395
        Initialize position value. Usually, the parser guard
eckhart's avatar
eckhart committed
396 397
        (`parsers.add_parser_guard()`) takes care of assigning the
        position in the document to newly created nodes. However,
Eckhart Arnold's avatar
Eckhart Arnold committed
398
        when Nodes are created outside the reach of the parser
eckhart's avatar
eckhart committed
399
        guard, their document-position must be assigned manually.
Eckhart Arnold's avatar
Eckhart Arnold committed
400 401
        Position values of the child nodes are assigned recursively, too.
        Returns the node itself for convenience.
eckhart's avatar
eckhart committed
402
        """
403 404 405 406
        # condition self.pos == pos cannot be assumed when tokens or whitespace
        # are dropped early!
        # assert self._pos < 0 or self.pos == pos, ("pos mismatch %i != %i at Node: %s"
        #                                           % (self._pos, pos, repr(self)))
Eckhart Arnold's avatar
Eckhart Arnold committed
407 408 409 410 411 412 413 414 415 416
        if pos != self._pos >= 0:
            raise AssertionError("Position value cannot be reassigned to a different value!")
        if self._pos < 0:
            self._pos = pos
            # recursively adjust pos-values of all children
            offset = self.pos
            for child in self.children:
                if child._pos < 0:
                    child.with_pos(offset)
                offset = child.pos + len(child)
eckhart's avatar
eckhart committed
417 418
        return self

419

420 421 422 423 424 425 426 427 428 429 430 431 432
    @property
    def attr(self):
        """
        Returns a dictionary of XML-attr attached to the node.
        """
        try:
            if self._xml_attr is None:          # cython compatibility
                self._xml_attr = OrderedDict()
        except AttributeError:
            self._xml_attr = OrderedDict()
        return self._xml_attr


eckhart's avatar
eckhart committed
433 434 435 436 437 438 439 440 441 442 443 444 445
    def attr_active(self) -> bool:
        """
        Returns True, if XML-Attributes of this node have ever been set
        or queried, even if unsuccessfully.
        """
        try:
            if self._xml_attr is not None:
                return True
        except AttributeError:
            pass
        return False


446
    def compare_attr(self, other: 'Node') -> bool:
447
        """
448 449
        Returns True, if `self` and `other` have the same attributes with the
        same attribute values.
450
        """
451 452 453 454 455 456 457 458 459
        if self.attr_active():
            if other.attr_active():
                return self.attr == other.attr
            return len(self.attr) == 0
            # self has empty dictionary and other has no attributes
        elif other.attr_active():
            return len(other.attr) == 0
            # other has empty attribute dictionary and self as no attributes
        return True  # neither self nor other have any attributes
460

Eckhart Arnold's avatar
Eckhart Arnold committed
461

462
    def _tree_repr(self, tab, open_fn, close_fn, data_fn=lambda i: i,
463
                   density=0, inline=False, inline_fn=lambda node: False) -> str:
464 465 466 467 468 469 470 471
        """
        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.

472
        Args:
473
            tab (str):  The indentation string, e.g. '\t' or '    '
eckhart's avatar
eckhart committed
474
            open_fn:   (Node->str) A function that returns an opening
475
                string (e.g. an XML-tag_name) for a given node
eckhart's avatar
eckhart committed
476
            close_fn:  (Node->str) A function that returns a closeF
477
                string (e.g. an XML-tag_name) for a given node.
eckhart's avatar
eckhart committed
478
            data_fn:   (str->str) A function that filters the data string
479 480 481 482 483 484
                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
485 486
        head = open_fn(self)
        tail = close_fn(self)
487 488

        if not self.result:
489
            return head.rstrip() + tail.lstrip()
490

eckhart's avatar
eckhart committed
491
        tail = tail.lstrip(None if density & 2 else '')
492

493
        inline = inline or inline_fn(self)
494 495 496 497 498
        if inline:
            head = head.rstrip()
            tail = tail.lstrip()
            usetab, sep = '', ''
        else:
eckhart's avatar
eckhart committed
499 500
            usetab = tab if head else ''    # no indentation if tag is already omitted
            sep = '\n'
501

502 503
        if self.children:
            content = []
504
            for child in self.children:
505
                subtree = child._tree_repr(tab, open_fn, close_fn, data_fn,
506
                                           density, inline, inline_fn)
eckhart's avatar
eckhart committed
507
                if subtree:
eckhart's avatar
eckhart committed
508 509
                    st = [subtree] if inline else subtree.split('\n')
                    content.append((sep + usetab).join(s for s in st))
510
            return head + usetab + (sep + usetab).join(content) + tail
511

eckhart's avatar
eckhart committed
512
        res = self.content
eckhart's avatar
eckhart committed
513
        if not inline and not head:
eckhart's avatar
eckhart committed
514
            # strip whitespace for omitted non inline node, e.g. CharData in mixed elements
eckhart's avatar
eckhart committed
515
            res = res.strip()
516 517
        if density & 1 and res.find('\n') < 0:  # and head[0] == "<":
            # except for XML, add a gap between opening statement and content
518
            gap = ' ' if not inline and head and head.rstrip()[-1:] != '>' else ''
eckhart's avatar
eckhart committed
519
            return head.rstrip() + gap + data_fn(res) + tail.lstrip()
520
        else:
521
            return head + '\n'.join([usetab + data_fn(s) for s in res.split('\n')]) + tail
522

Eckhart Arnold's avatar
Eckhart Arnold committed
523

524 525
    def as_sxpr(self, src: str = None,
                indentation: int = 2,
526
                compact: bool = False) -> str:
527
        """
528 529
        Returns content as S-expression, i.e. in lisp-like form. If this
        method is callad on a RootNode-object,
530

531
        Args:
532 533 534
            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.
535 536
            indentation: The number of whitespaces for indentation
            compact:  If True, a compact representation is returned where
537
                brackets are omitted and only the indentation indicates the
Eckhart Arnold's avatar
Eckhart Arnold committed
538
                tree structure.
539 540
        """

eckhart's avatar
eckhart committed
541
        left_bracket, right_bracket, density = ('', '', 1) if compact else ('(', '\n)', 0)
eckhart's avatar
eckhart committed
542
        lbreaks = linebreaks(src) if src else []  # type: List[int]
543
        root = cast(RootNode, self) if isinstance(self, RootNode) else None  # type: Optional[Node]
544

545
        def opening(node) -> str:
eckhart's avatar
eckhart committed
546
            """Returns the opening string for the representation of `node`."""
eckhart's avatar
eckhart committed
547
            txt = [left_bracket, node.tag_name]
548
            # s += " '(pos %i)" % node.add_pos
549
            # txt.append(str(id(node)))  # for debugging
eckhart's avatar
eckhart committed
550
            if node.attr_active():
551
                txt.extend(' `(%s "%s")' % (k, v) for k, v in node.attr.items())
552
            if src:
553 554
                line, col = line_col(lbreaks, node.pos)
                txt.append(" `(pos %i %i %i)" % (node.pos, line, col))
555 556
            if root and id(node) in root.error_nodes:
                txt.append(" `(err `%s)" % ' '.join(str(err) for err in root.get_errors(node)))
557
            return "".join(txt) + '\n'
558

eckhart's avatar
eckhart committed
559 560 561
        def closing(node) -> str:
            """Returns the closing string for the representation of `node`."""
            return right_bracket
562

eckhart's avatar
eckhart committed
563 564 565 566 567
        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'\"')
568

569
        return self._tree_repr(' ' * indentation, opening, closing, pretty, density=density)
Eckhart Arnold's avatar
Eckhart Arnold committed
570

eckhart's avatar
eckhart committed
571

572 573
    def as_xml(self, src: str = None,
               indentation: int = 2,
eckhart's avatar
eckhart committed
574 575 576
               inline_tags: Set[str] = set(),
               omit_tags: Set[str] = set(),
               empty_tags: Set[str] = set()) -> str:
577 578 579
        """
        Returns content as XML-tree.

580
        Args:
581 582 583
            src:  The source text or `None`. In case the source text is
                given the position will also be reported as line and
                column.
584
            indentation: The number of whitespaces for indentation
585 586 587
            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
588
                neither the opening tag nor its attr nor the closing tag. This
589 590 591
                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.
592 593
            empty_tags:  A set of tags which shall be rendered as empty elements, e.g.
                "<empty/>" instead of "<empty><empty>".
594
        """
595
        root = cast(RootNode, self) if isinstance(self, RootNode) else None  # type: Optional[Node]
596

597
        def opening(node) -> str:
598 599 600
            """Returns the opening string for the representation of `node`."""
            if node.tag_name in omit_tags:
                return ''
eckhart's avatar
eckhart committed
601
            txt = ['<', node.tag_name]
eckhart's avatar
eckhart committed
602
            has_reserved_attrs = node.attr_active() \
eckhart's avatar
eckhart committed
603
                and any(r in node.attr for r in {'err', 'line', 'col'})
eckhart's avatar
eckhart committed
604
            if node.attr_active():
605
                txt.extend(' %s="%s"' % (k, v) for k, v in node.attr.items())
606
            if src and not has_reserved_attrs:
eckhart's avatar
eckhart committed
607
                txt.append(' line="%i" col="%i"' % line_col(line_breaks, node.pos))
608
            if root and id(node) in root.error_nodes and not has_reserved_attrs:
eckhart's avatar
eckhart committed
609
                txt.append(' err="%s"' % ''.join(str(err).replace('"', r'\"')
610
                                                 for err in root.get_error(node)))
611 612 613
            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
614
                ending = "/>\n" if not node.tag_name[0] == '?' else "?>\n"
615 616 617
            else:
                ending = ">\n"
            return "".join(txt + [ending])
618 619

        def closing(node):
620
            """Returns the closing string for the representation of `node`."""
621
            if node.tag_name in omit_tags or node.tag_name in empty_tags:
622
                return ''
623
            return ('\n</') + node.tag_name + '>'
624

625 626 627 628 629 630 631
        def sanitizer(content: str) -> str:
            """Substitute "&", "<", ">" in XML-content by the respective entities."""
            content = RX_AMP.sub('&amp;', content)
            content = content.replace('<', '&lt;').replace('>', '&gt;')
            return content


632 633 634 635 636
        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.
            """
eckhart's avatar
eckhart committed
637
            return node.tag_name in inline_tags \
eckhart's avatar
eckhart committed
638
                or (node.attr_active()
eckhart's avatar
eckhart committed
639
                    and node.attr.get('xml:space', 'default') == 'preserve')
640

641
        line_breaks = linebreaks(src) if src else []
642
        return self._tree_repr(' ' * indentation, opening, closing, sanitizer,
643
                               density=1, inline_fn=inlining)
644

Eckhart Arnold's avatar
Eckhart Arnold committed
645

eckhart's avatar
eckhart committed
646
    def select(self, match_function: Callable, include_root: bool = False, reverse: bool = False) \
647
            -> Iterator['Node']:
eckhart's avatar
eckhart committed
648
        """
649
        Finds nodes in the tree that fulfill a given criterion.
eckhart's avatar
eckhart committed
650

651
        `select` is a generator that yields all nodes for which the
di68kap's avatar
di68kap committed
652
        given `match_function` evaluates to True. The tree is
653 654 655
        traversed pre-order.

        See function `Node.select_by_tag` for some examples.
eckhart's avatar
eckhart committed
656

657 658 659
        Args:
            match_function (function): A function  that takes as Node
                object as argument and returns True or False
660 661
            include_root (bool): If False, only descendant nodes will be
                checked for a match.
662 663
            reverse (bool): If True, the tree will be walked in reverse
                order, i.e. last children first.
664
        Yields:
665
            Node: All nodes of the tree for which
666 667
            ``match_function(node)`` returns True
        """
668
        if include_root and match_function(self):
669
            yield self
670 671 672
        child_iterator = reversed(self.children) if reverse else self.children
        for child in child_iterator:
            for node in child.select(match_function, True, reverse):
eckhart's avatar
eckhart committed
673
                yield node
674

Eckhart Arnold's avatar
Eckhart Arnold committed
675

eckhart's avatar
eckhart committed
676
    def select_by_tag(self, tag_names: Union[str, AbstractSet[str]],
eckhart's avatar
eckhart committed
677
                      include_root: bool = False) -> Iterator['Node']:
678
        """
679 680 681 682
        Returns an iterator that runs through all descendants that have one
        of the given tag names.

        Examples::
683

684
            >>> tree = parse_sxpr('(a (b "X") (X (c "d")) (e (X "F")))')
685
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag("X", False))
686
            ['(X (c "d"))', '(X "F")']
687
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag({"X", "b"}, False))
688
            ['(b "X")', '(X (c "d"))', '(X "F")']
689
            >>> any(tree.select_by_tag('a', False))
690
            False
691
            >>> list(flatten_sxpr(item.as_sxpr()) for item in tree.select_by_tag('a', True))
692
            ['(a (b "X") (X (c "d")) (e (X "F")))']
693 694
            >>> flatten_sxpr(next(tree.select_by_tag("X", False)).as_sxpr())
            '(X (c "d"))'
695 696

        Args:
697 698 699 700
            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.
701 702 703
        Yields:
            Node: All nodes which have a given tag name.
        """
704
        if isinstance(tag_names, str):
eckhart's avatar
eckhart committed
705
            tag_names = frozenset({tag_names})
706
        return self.select(lambda node: node.tag_name in tag_names, include_root)
707 708


709 710 711 712
    def pick(self, tag_names: Union[str, Set[str]]) -> Optional['Node']:
        """
        Picks the first descendant with one of the given tag_names.

713
        This function is mostly just syntactic sugar for
714 715 716 717 718 719 720 721 722 723
        ``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


724
    def tree_size(self) -> int:
eckhart's avatar
eckhart committed
725 726 727
        """
        Recursively counts the number of nodes in the tree including the root node.
        """
728 729 730
        return sum(child.tree_size() for child in self.children) + 1


731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
class FrozenNode(Node):

    def __init__(self, tag_name: str, result: ResultType) -> None:
        if isinstance(result, str) or isinstance(result, StringView):
            result = str(result)
        else:
            raise TypeError('FrozenNode only accepts string as results. '
                            '(Only leaf-nodes can be frozen nodes.)')
        super(FrozenNode, self).__init__(tag_name, result, True)

    @property
    def result(self) -> StrictResultType:
        return self._result

    @result.setter
    def result(self, result: ResultType):
        raise TypeError('FrozenNode does not allow re-assignment of results.')

eckhart's avatar
eckhart committed
749 750 751 752
    @property
    def attr(self):
        raise AssertionError("Attributes cannot be accessed on a frozen node")

753 754 755 756 757 758 759 760
    # @property
    # def errors(self) -> List[Error]:
    #     return ()
    #
    # @errors.setter
    # def errors(self, errors: List[Error]):
    #     if errors:
    #         raise AssertionError('Cannot assign error list to frozen node')
eckhart's avatar
eckhart committed
761

Eckhart Arnold's avatar
Eckhart Arnold committed
762
    def with_pos(self, pos: int) -> 'Node':
763 764 765 766
        pass


PLACEHOLDER = Node('__PLACEHOLDER__', '')
di68kap's avatar
di68kap committed
767 768


769 770 771 772 773 774 775 776 777 778
def tree_sanity_check(tree: Node) -> bool:
    node_set = set()
    for node in tree.select(lambda nd: True, include_root=True):
        if node in node_set and not (isinstance(node, FrozenNode)
                                     or node.tag_name == '__PLACEHOLDER__'):
            return False
        node_set.add(node)
    return True


di68kap's avatar
di68kap committed
779
class RootNode(Node):
780
    """TODO: Add Documentation!!!
di68kap's avatar
di68kap committed
781

782
        errors (list):  A list of all errors that have occured so far during
783 784
                processing (i.e. parsing, AST-transformation, compiling)
                of this tree.
di68kap's avatar
di68kap committed
785

786 787
        error_flag (int):  the highest warning or error level of all errors
                that occurred.
di68kap's avatar
di68kap committed
788
    """
789

eckhart's avatar
eckhart committed
790
    def __init__(self, node: Optional[Node] = None):
791
        super().__init__('__not_yet_ready__', '')
792
        self.errors = []           # type: List[Error]
793 794
        self.error_nodes = dict()      # type: Dict[int, List[Error]]  # id(node) -> error list
        self.error_positions = dict()  # type: Dict[int, Set[int]]  # pos -> set of id(node)
di68kap's avatar
di68kap committed
795
        self.error_flag = 0
eckhart's avatar
eckhart committed
796 797
        if node is not None:
            self.swallow(node)
798
        # customization for XML-Representation
eckhart's avatar
eckhart committed
799 800 801
        self.inline_tags = set()  # type: Set[str]
        self.omit_tags = set()  # type: Set[str]
        self.empty_tags = set()  # type: Set[str]
di68kap's avatar
di68kap committed
802

803 804 805 806 807 808 809 810 811 812
    def __deepcopy__(self, memodict={}):
        duplicate = self.__class__(None)
        if self.children:
            duplicate.children = copy.deepcopy(self.children)
            duplicate._result = duplicate.children
        else:
            duplicate.children = NoChildren
            duplicate._result = self._result
        duplicate._pos = self._pos
        duplicate._len = self._len
eckhart's avatar
eckhart committed
813
        if self.attr_active():
di68kap's avatar
di68kap committed
814
            duplicate.attr.update(copy.deepcopy(self._xml_attr))
815
            # duplicate._xml_attr = copy.deepcopy(self._xml_attr)  # this is blocked by cython
816
        duplicate.errors = copy.copy(self.errors)
817 818
        duplicate.error_nodes = copy.copy(self.error_nodes)
        duplicate.error_positions = copy.deepcopy(self.error_positions)
819 820 821 822
        duplicate.error_flag = self.error_flag
        duplicate.inline_tags = self.inline_tags
        duplicate.omit_tags = self.omit_tags
        duplicate.empty_tags = self.empty_tags
823
        duplicate.tag_name = self.tag_name
824 825 826
        return duplicate


827
    def swallow(self, node: Node) -> 'RootNode':
828 829
        """
        Put `self` in the place of `node` by copying all its data.
830 831 832 833 834 835 836 837 838
        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
839 840 841 842
        self._result = node._result
        self.children = node.children
        self._len = node._len
        self._pos = node._pos
843
        self.tag_name = node.tag_name
eckhart's avatar
eckhart committed
844
        if node.attr_active():
845
            self._xml_attr = node._xml_attr
di68kap's avatar
di68kap committed
846
        self._content = node._content
847 848
        if id(node) in self.error_nodes:
            self.error_nodes[id(self)] = self.error_nodes[id(node)]
849
        return self
di68kap's avatar
di68kap committed
850

eckhart's avatar
eckhart committed
851
    def add_error(self, node: Node, error: Error) -> 'RootNode':
852 853 854
        """
        Adds an Error object to the tree, locating it at a specific node.
        """
eckhart's avatar