"""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. """ import collections.abc import copy import os from functools import partial try: import regex as re except ImportError: import re try: from typing import AbstractSet, Any, ByteString, Callable, cast, Container, Dict, \ Iterator, Iterable, List, NamedTuple, Sequence, Union, Text, Tuple, Hashable except ImportError: from .typing34 import AbstractSet, Any, ByteString, Callable, cast, Container, Dict, \ Iterator, Iterable, List, NamedTuple, Sequence, Union, Text, Tuple, Hashable from DHParser.toolkit import is_logging, log_dir, identity from DHParser.stringview import StringView from DHParser.error import Error, linebreaks, line_col __all__ = ('ParserBase', 'WHITESPACE_PTYPE', 'TOKEN_PTYPE', 'MockParser', 'ZombieParser', 'ZOMBIE_PARSER', 'Node', 'mock_syntax_tree', 'TransformationFunc') ####################################################################### # # 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()): self._name = name # type: str 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) @property def name(self): return self._name @property def ptype(self) -> str: return self._ptype @property def repr(self) -> str: return self.name if self.name else repr(self) WHITESPACE_PTYPE = ':Whitespace' TOKEN_PTYPE = ':Token' class MockParser(ParserBase): """ MockParser objects can be used to reconstruct syntax trees from a serialized form like S-expressions or XML. Mock objects can mimic different parser types by assigning them a ptype on initialization. Mock objects should not be used for anything other than syntax tree (re-)construction. In all other cases where a parser object substitute is needed, chose the singleton ZOMBIE_PARSER. """ def __init__(self, name='', ptype=''): # , pbases=frozenset()): assert not ptype or ptype[0] == ':' super().__init__(name) 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 # ####################################################################### ChildrenType = Tuple['Node', ...] StrictResultType = Union[ChildrenType, StringView, str] ResultType = Union[ChildrenType, 'Node', StringView, str, None] def flatten_sxpr(sxpr: str) -> str: """Returns S-expression `sxpr` as a one-liner without unnecessary whitespace. Example: >>> flatten_sxpr('(a\\n (b\\n c\\n )\\n)\\n') '(a (b c))' """ return re.sub('\s(?=\))', '', re.sub('\s+', ' ', sxpr)).strip() class Node(collections.abc.Sized): """ Represents a node in the concrete or abstract syntax tree. Attributes: tag_name (str): The name of the node, which is either its parser's name or, if that is empty, the parser's class name result (str or tuple): The result of the parser which generated this node, which can be either a string or a tuple of child nodes. children (tuple): The tuple of child nodes or an empty tuple if there are no child nodes. READ ONLY! parser (Parser): The parser which generated this node. WARNING: In case you use mock syntax trees for testing or parser replacement during the AST-transformation: DO NOT rely on this being a real parser object in any phase after parsing (i.e. AST-transformation and compiling), for example by calling ``isinstance(node.parer, ...)``. errors (list): A list of parser- or compiler-errors: tuple(position, string) attached to this node 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. len (int): The full length of the node's string result if the node is a leaf node or, otherwise, the concatenated string result's of its descendants. The figure always represents the length before AST-transformation ans will never change through AST-transformation. READ ONLY! pos (int): the position of the node within the parsed text. The value of ``pos`` is -1 meaning invalid by default. Setting this value will set the positions of all child nodes relative to this value. To set the pos values of all nodes in a syntax tree, the pos value of the root node should be set to 0 right after parsing. Other than that, this value should be considered READ ONLY. At any rate, it should only be reassigned only during parsing stage and never during or after the AST-transformation. """ __slots__ = ['_result', 'children', '_errors', '_len', '_pos', 'parser', 'error_flag'] def __init__(self, parser, result: ResultType) -> None: """Initializes the ``Node``-object with the ``Parser``-Instance that generated the node and the parser's result. """ # self._result = '' # type: StrictResultType # self.children = () # type: ChildrenType self.error_flag = 0 # type: bool self._errors = [] # type: List[Error] self.result = result self._len = len(self._result) if not self.children else \ sum(child._len for child in self.children) # type: int # self.pos: int = 0 # continuous updating of pos values wastes a lot of time self._pos = -1 # type: int self.parser = parser or ZOMBIE_PARSER def __str__(self): if self.children: return "".join(str(child) for child in self.children) return str(self.result) 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) def __len__(self): return self._len def __bool__(self): # A node that is not None is always True, even if it's empty return True def __eq__(self, other): # return str(self.parser) == str(other.parser) and self.result == other.result return self.tag_name == other.tag_name and self.result == other.result def __hash__(self): return hash(self.tag_name) def __deepcopy__(self, memodict={}): result = copy.deepcopy(self.result) other = Node(self.parser, result) other._pos = self._pos return other @property # this needs to be a (dynamic) property, in case sef.parser gets updated def tag_name(self) -> str: return self.parser.name or self.parser.ptype @property def result(self) -> StrictResultType: return self._result @result.setter def result(self, result: ResultType): # # made obsolete by static type checking with mypy # assert ((isinstance(result, tuple) and all(isinstance(child, Node) for child in result)) # or isinstance(result, Node) # or isinstance(result, str)), str(result) # Possible optimization: Do not allow single nodes as argument: # assert not isinstance(result, Node) self._result = (result,) if isinstance(result, Node) else str(result) \ if isinstance(result, StringView) else result or '' # type: StrictResultType self.children = cast(ChildrenType, self._result) \ if isinstance(self._result, tuple) else cast(ChildrenType, ()) # type: ChildrenType if self.children: self.error_flag = max(self.error_flag, max(child.error_flag for child in self.children)) # type: bool @property def pos(self) -> int: assert self._pos >= 0, "position value not initialized!" return self._pos @pos.setter def pos(self, pos: int): self._pos = pos offset = 0 # recursively adjust pos-values of all children for child in self.children: child.pos = pos + offset offset += len(child) # add pos-values to Error-objects for err in self._errors: err.pos = pos @property def errors(self) -> List[Error]: return self._errors.copy() def add_error(self, message: str, level: int = Error.ERROR, code: Hashable = 0) -> 'Node': self._errors.append(Error(message, level, code)) self.error_flag = max(self.error_flag, self._errors[-1].level) return self def collect_errors(self, document: Union[StringView, str] = '', clear_errors=False) -> List[ Error]: """ Recursively adds line- and column-numbers to all error objects. 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. """ if self.error_flag: lbreaks = linebreaks(document) if document else [] return self._collect_errors(lbreaks, clear_errors) else: return [] def _collect_errors(self, lbreaks: List[int] = [], clear_errors=False) -> List[Error]: if self.error_flag: errors = self.errors if lbreaks: for err in errors: err.pos = self.pos err.line, err.column = line_col(lbreaks, err.pos) if clear_errors: self._errors = [] self.error_flag = 0 if self.children: for child in self.children: errors.extend(child._collect_errors(lbreaks, clear_errors)) return errors else: return [] def _tree_repr(self, tab, openF, closeF, dataF=identity, density=0) -> str: """ 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. Args: tab (str): The indentation string, e.g. '\t' or ' ' openF: (Node->str) A function that returns an opening string (e.g. an XML-tag_name) for a given node closeF: (Node->str) A function that returns a closeF string (e.g. an XML-tag_name) for a given node. dataF: (str->str) A function that filters the data string before printing, e.g. to add quotation marks Returns (str): A string that contains a (serialized) tree representation of the node and its children. """ head = openF(self) tail = closeF(self) if not self.result: return head.rstrip() + tail.lstrip() D = None if density & 2 else '' if self.children: content = [] for child in self.children: subtree = child._tree_repr(tab, openF, closeF, dataF, density).split('\n') content.append('\n'.join((tab + s) for s in subtree)) return head + '\n'.join(content) + tail.lstrip(D) res = cast(str, self.result) # safe, because if there are no children, result is a string if density & 1 and res.find('\n') < 0: # and head[0] == "<": # except for XML, add a gap between opening statement and content gap = ' ' if head.rstrip()[-1] != '>' else '' return head.rstrip() + gap + dataF(self.result) + tail.lstrip() else: return head + '\n'.join([tab + dataF(s) for s in res.split('\n')]) + tail.lstrip(D) def as_sxpr(self, src: str=None, compact: bool=False) -> str: """ Returns content as S-expression, i.e. in lisp-like form. Args: 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. compact: If True a compact representation is returned where brackets are ommited and only the indentation indicates the tree structure. """ lB, rB, D = ('', '', 1) if compact else ('(', '\n)', 0) def opening(node) -> str: s = lB + node.tag_name # s += " '(pos %i)" % node.pos if src: s += " '(pos %i " % node.pos # + " %i %i)" % line_col(src, node.pos) if node.errors: s += " '(err '(%s))" % ' '.join(str(err).replace('"', r'\"') for err in node.errors) return s + '\n' def pretty(s): return '"%s"' % s if s.find('"') < 0 \ else "'%s'" % s if s.find("'") < 0 \ else '"%s"' % s.replace('"', r'\"') return self._tree_repr(' ', opening, lambda node: rB, pretty, density=D) def as_xml(self, src: str=None) -> str: """ Returns content as XML-tree. Args: src: The source text or `None`. In case the source text is given the position will also be reported as line and column. """ def opening(node) -> str: s = '<' + node.tag_name # s += ' pos="%i"' % node.pos if src: s += ' line="%i" col="%i"' % line_col(src, node.pos) if node.errors: s += ' err="%s"' % ''.join(str(err).replace('"', r'\"') for err in node.errors) return s + ">\n" def closing(node): return '\n' return self._tree_repr(' ', opening, closing, density=1) 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()) def content(self) -> str: """ Returns content as string, inserting error messages where errors occurred. """ s = "".join(child.content() for child in self.children) if self.children \ else str(self.result) return (' <<< Error on "%s" | %s >>> ' % (s, '; '.join(e.message for e in self._errors))) if self._errors else s def find(self, match_function: Callable) -> Iterator['Node']: """Finds nodes in the tree that match a specific criterion. ``find`` is a generator that yields all nodes for which the given ``match_function`` evaluates to True. The tree is traversed pre-order. Args: match_function (function): A function that takes as Node object as argument and returns True or False Yields: Node: all nodes of the tree for which ``match_function(node)`` returns True """ if match_function(self): yield self else: for child in self.children: for nd in child.find(match_function): yield nd def tree_size(self) -> int: """Recursively counts the number of nodes in the tree including the root node.""" return sum(child.tree_size() for child in self.children) + 1 def log(self, log_file_name): if is_logging(): 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: f.write(self.as_sxpr()) def mock_syntax_tree(sxpr): """ Generates a tree of nodes from an S-expression. Example: >>> mock_syntax_tree("(a (b c))").as_sxpr() '(a\\n (b\\n "c"\\n )\\n)' """ def next_block(s): s = s.strip() while s[0] != ')': if s[0] != '(': raise ValueError('"(" expected, not ' + s[:10]) # assert s[0] == '(', s level = 1 i = 1 while level > 0: if s[i] == '(': level += 1 elif s[i] == ')': level -= 1 i += 1 yield s[:i] s = s[i:].strip() sxpr = sxpr.strip() if sxpr[0] != '(': raise ValueError('"(" expected, not ' + sxpr[:10]) # assert sxpr[0] == '(', sxpr sxpr = sxpr[1:].strip() m = re.match('[\w:]+', sxpr) name, class_name = (sxpr[:m.end()].split(':') + [''])[:2] sxpr = sxpr[m.end():].strip() if sxpr[0] == '(': result = tuple(mock_syntax_tree(block) for block in next_block(sxpr)) else: lines = [] while sxpr and sxpr[0] != ')': for qm in ['"""', "'''", '"', "'"]: m = re.match(qm + r'.*?' + qm, sxpr, re.DOTALL) if m: i = len(qm) lines.append(sxpr[i:m.end() - i]) sxpr = sxpr[m.end():].strip() break else: m = re.match(r'(?:(?!\)).)*', sxpr, re.DOTALL) lines.append(sxpr[:m.end()]) sxpr = sxpr[m.end():] result = "\n".join(lines) return Node(MockParser(name, ':' + class_name), result) TransformationFunc = Union[Callable[[Node], Any], partial] # 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())