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Python Compiled Bytecode | 2009-11-11 | 28.0 KB | 896 lines

# Source Generated with Decompyle++
# File: in.pyc (Python 2.6)

"""Python parse tree definitions.

This is a very concrete parse tree; we need to keep every token and
even the comments and whitespace between tokens.

There's also a pattern matching implementation here.
"""
__author__ = 'Guido van Rossum <[e-mail]>'
import sys
from StringIO import StringIO
HUGE = 2147483647
_type_reprs = { }

def type_repr(type_num):
    if not _type_reprs:
        python_symbols = python_symbols
        import pygram
        for name, val in python_symbols.__dict__.items():
            if type(val) == int:
                _type_reprs[val] = name
                continue


    return _type_reprs.setdefault(type_num, type_num)


class Base(object):
    '''Abstract base class for Node and Leaf.

    This provides some default functionality and boilerplate using the
    template pattern.

    A node may be a subnode of at most one parent.
    '''
    type = None
    parent = None
    children = ()
    was_changed = False

    def __new__(cls, *args, **kwds):
        '''Constructor that prevents Base from being instantiated.'''
        if not cls is not Base:
            raise AssertionError, 'Cannot instantiate Base'
        return object.__new__(cls)


    def __eq__(self, other):
        '''Compares two nodes for equality.

        This calls the method _eq().
        '''
        if self.__class__ is not other.__class__:
            return NotImplemented
        return self._eq(other)


    def __ne__(self, other):
        '''Compares two nodes for inequality.

        This calls the method _eq().
        '''
        if self.__class__ is not other.__class__:
            return NotImplemented
        return not self._eq(other)


    def _eq(self, other):
        '''Compares two nodes for equality.

        This is called by __eq__ and __ne__.  It is only called if the
        two nodes have the same type.  This must be implemented by the
        concrete subclass.  Nodes should be considered equal if they
        have the same structure, ignoring the prefix string and other
        context information.
        '''
        raise NotImplementedError


    def clone(self):
        '''Returns a cloned (deep) copy of self.

        This must be implemented by the concrete subclass.
        '''
        raise NotImplementedError


    def post_order(self):
        '''Returns a post-order iterator for the tree.

        This must be implemented by the concrete subclass.
        '''
        raise NotImplementedError


    def pre_order(self):
        '''Returns a pre-order iterator for the tree.

        This must be implemented by the concrete subclass.
        '''
        raise NotImplementedError


    def set_prefix(self, prefix):
        '''Sets the prefix for the node (see Leaf class).

        This must be implemented by the concrete subclass.
        '''
        raise NotImplementedError


    def get_prefix(self):
        '''Returns the prefix for the node (see Leaf class).

        This must be implemented by the concrete subclass.
        '''
        raise NotImplementedError


    def replace(self, new):
        '''Replaces this node with a new one in the parent.'''
        if not self.parent is not None:
            raise AssertionError, str(self)
        if not new is not None:
            raise AssertionError
        l_children = []
        found = False
        for ch in self.parent.children:
            if ch is self:
                if not not found:
                    raise AssertionError, (self.parent.children, self, new)
                found = True
                continue
            None if new is not None else None if not isinstance(new, list) else self.parent is not None
            l_children.append(ch)

        if not found:
            raise AssertionError, (self.children, self, new)
        self.parent.changed()
        self.parent.children = l_children
        for x in new:
            x.parent = self.parent

        self.parent = None


    def get_lineno(self):
        '''Returns the line number which generated the invocant node.'''
        node = self
        while not isinstance(node, Leaf):
            if not node.children:
                return None
            node = node.children[0]
            continue
            node.children
        return node.lineno


    def changed(self):
        if self.parent:
            self.parent.changed()

        self.was_changed = True


    def remove(self):
        """Remove the node from the tree. Returns the position of the node
        in its parent's children before it was removed."""
        if self.parent:
            for i, node in enumerate(self.parent.children):
                if node is self:
                    self.parent.changed()
                    del self.parent.children[i]
                    self.parent = None
                    return i




    def get_next_sibling(self):
        """Return the node immediately following the invocant in their
        parent's children list. If the invocant does not have a next
        sibling, return None."""
        if self.parent is None:
            return None
        for i, child in enumerate(self.parent.children):
            if child is self:

                try:
                    return self.parent.children[i + 1]
                except IndexError:
                    self.parent is None
                    self.parent is None
                    return None


            self.parent is None<EXCEPTION MATCH>IndexError



    def get_prev_sibling(self):
        """Return the node immediately preceding the invocant in their
        parent's children list. If the invocant does not have a previous
        sibling, return None."""
        if self.parent is None:
            return None
        for i, child in enumerate(self.parent.children):
            if child is self:
                if i == 0:
                    return None
                return self.parent.children[i - 1]



    def get_suffix(self):
        '''Return the string immediately following the invocant node. This
        is effectively equivalent to node.get_next_sibling().get_prefix()'''
        next_sib = self.get_next_sibling()
        if next_sib is None:
            return ''
        return next_sib.get_prefix()



class Node(Base):
    '''Concrete implementation for interior nodes.'''

    def __init__(self, type, children, context = None, prefix = None):
        '''Initializer.

        Takes a type constant (a symbol number >= 256), a sequence of
        child nodes, and an optional context keyword argument.

        As a side effect, the parent pointers of the children are updated.
        '''
        if not type >= 256:
            raise AssertionError, type
        self.type = type
        self.children = list(children)
        for ch in self.children:
            if not ch.parent is None:
                raise AssertionError, repr(ch)
            ch.parent = self



    def __repr__(self):
        '''Returns a canonical string representation.'''
        return '%s(%s, %r)' % (self.__class__.__name__, type_repr(self.type), self.children)


    def __str__(self):
        '''Returns a pretty string representation.

        This reproduces the input source exactly.
        '''
        return ''.join(map(str, self.children))


    def _eq(self, other):
        '''Compares two nodes for equality.'''
        return (self.type, self.children) == (other.type, other.children)


    def clone(self):
        '''Returns a cloned (deep) copy of self.'''
        return []([], [ ch.clone() for ch in self.children ])


    def post_order(self):
        '''Returns a post-order iterator for the tree.'''
        for child in self.children:
            for node in child.post_order():
                yield node


        yield self


    def pre_order(self):
        '''Returns a pre-order iterator for the tree.'''
        yield self
        for child in self.children:
            for node in child.post_order():
                yield node




    def set_prefix(self, prefix):
        '''Sets the prefix for the node.

        This passes the responsibility on to the first child.
        '''
        if self.children:
            self.children[0].set_prefix(prefix)



    def get_prefix(self):
        '''Returns the prefix for the node.

        This passes the call on to the first child.
        '''
        if not self.children:
            return ''
        return self.children[0].get_prefix()


    def set_child(self, i, child):
        """Equivalent to 'node.children[i] = child'. This method also sets the
        child's parent attribute appropriately."""
        child.parent = self
        self.children[i].parent = None
        self.children[i] = child
        self.changed()


    def insert_child(self, i, child):
        """Equivalent to 'node.children.insert(i, child)'. This method also
        sets the child's parent attribute appropriately."""
        child.parent = self
        self.children.insert(i, child)
        self.changed()


    def append_child(self, child):
        """Equivalent to 'node.children.append(child)'. This method also
        sets the child's parent attribute appropriately."""
        child.parent = self
        self.children.append(child)
        self.changed()



class Leaf(Base):
    '''Concrete implementation for leaf nodes.'''
    prefix = ''
    lineno = 0
    column = 0

    def __init__(self, type, value, context = None, prefix = None):
        '''Initializer.

        Takes a type constant (a token number < 256), a string value,
        and an optional context keyword argument.
        '''
        if type <= type:
            pass
        elif not type < 256:
            raise AssertionError, type
        if context is not None:
            (self.lineno, self.column) = (self.prefix,)

        self.type = type
        self.value = value
        if prefix is not None:
            self.prefix = prefix



    def __repr__(self):
        '''Returns a canonical string representation.'''
        return '%s(%r, %r)' % (self.__class__.__name__, self.type, self.value)


    def __str__(self):
        '''Returns a pretty string representation.

        This reproduces the input source exactly.
        '''
        return self.prefix + str(self.value)


    def _eq(self, other):
        '''Compares two nodes for equality.'''
        return (self.type, self.value) == (other.type, other.value)


    def clone(self):
        '''Returns a cloned (deep) copy of self.'''
        return Leaf(self.type, self.value, (self.prefix, (self.lineno, self.column)))


    def post_order(self):
        '''Returns a post-order iterator for the tree.'''
        yield self


    def pre_order(self):
        '''Returns a pre-order iterator for the tree.'''
        yield self


    def set_prefix(self, prefix):
        '''Sets the prefix for the node.'''
        self.changed()
        self.prefix = prefix


    def get_prefix(self):
        '''Returns the prefix for the node.'''
        return self.prefix



def convert(gr, raw_node):
    '''Converts raw node information to a Node or Leaf instance.

    This is passed to the parser driver which calls it whenever a
    reduction of a grammar rule produces a new complete node, so that
    the tree is build strictly bottom-up.
    '''
    (type, value, context, children) = raw_node
    if children or type in gr.number2symbol:
        if len(children) == 1:
            return children[0]
        return Node(type, children, context = context)
    return Leaf(type, value, context = context)


class BasePattern(object):
    '''A pattern is a tree matching pattern.

    It looks for a specific node type (token or symbol), and
    optionally for a specific content.

    This is an abstract base class.  There are three concrete
    subclasses:

    - LeafPattern matches a single leaf node;
    - NodePattern matches a single node (usually non-leaf);
    - WildcardPattern matches a sequence of nodes of variable length.
    '''
    type = None
    content = None
    name = None

    def __new__(cls, *args, **kwds):
        '''Constructor that prevents BasePattern from being instantiated.'''
        if not cls is not BasePattern:
            raise AssertionError, 'Cannot instantiate BasePattern'
        return object.__new__(cls)


    def __repr__(self):
        args = [
            type_repr(self.type),
            self.content,
            self.name]
        while args and args[-1] is None:
            del args[-1]
        return '%s(%s)' % (self.__class__.__name__, ', '.join(map(repr, args)))


    def optimize(self):
        '''A subclass can define this as a hook for optimizations.

        Returns either self or another node with the same effect.
        '''
        return self


    def match(self, node, results = None):
        '''Does this pattern exactly match a node?

        Returns True if it matches, False if not.

        If results is not None, it must be a dict which will be
        updated with the nodes matching named subpatterns.

        Default implementation for non-wildcard patterns.
        '''
        if self.type is not None and node.type != self.type:
            return False
        if self.content is not None:
            r = None
            if results is not None:
                r = { }

            if not self._submatch(node, r):
                return False
            if r:
                results.update(r)


        if results is not None and self.name:
            results[self.name] = node

        return True


    def match_seq(self, nodes, results = None):
        '''Does this pattern exactly match a sequence of nodes?

        Default implementation for non-wildcard patterns.
        '''
        if len(nodes) != 1:
            return False
        return self.match(nodes[0], results)


    def generate_matches(self, nodes):
        '''Generator yielding all matches for this pattern.

        Default implementation for non-wildcard patterns.
        '''
        r = { }
        if nodes and self.match(nodes[0], r):
            yield (1, r)




class LeafPattern(BasePattern):

    def __init__(self, type = None, content = None, name = None):
        '''Initializer.  Takes optional type, content, and name.

        The type, if given must be a token type (< 256).  If not given,
        this matches any *leaf* node; the content may still be required.

        The content, if given, must be a string.

        If a name is given, the matching node is stored in the results
        dict under that key.
        '''
        if type is not None:
            if type <= type:
                pass
            elif not type < 256:
                raise AssertionError, type

        if content is not None:
            if not isinstance(content, basestring):
                raise AssertionError, repr(content)

        self.type = type
        self.content = content
        self.name = name


    def match(self, node, results = None):
        '''Override match() to insist on a leaf node.'''
        if not isinstance(node, Leaf):
            return False
        return BasePattern.match(self, node, results)


    def _submatch(self, node, results = None):
        """Match the pattern's content to the node's children.

        This assumes the node type matches and self.content is not None.

        Returns True if it matches, False if not.

        If results is not None, it must be a dict which will be
        updated with the nodes matching named subpatterns.

        When returning False, the results dict may still be updated.
        """
        return self.content == node.value



class NodePattern(BasePattern):
    wildcards = False

    def __init__(self, type = None, content = None, name = None):
        """Initializer.  Takes optional type, content, and name.

        The type, if given, must be a symbol type (>= 256).  If the
        type is None this matches *any* single node (leaf or not),
        except if content is not None, in which it only matches
        non-leaf nodes that also match the content pattern.

        The content, if not None, must be a sequence of Patterns that
        must match the node's children exactly.  If the content is
        given, the type must not be None.

        If a name is given, the matching node is stored in the results
        dict under that key.
        """
        if type is not None:
            if not type >= 256:
                raise AssertionError, type

        if content is not None:
            if not not isinstance(content, basestring):
                raise AssertionError, repr(content)
            content = list(content)
            for i, item in enumerate(content):
                if not isinstance(item, BasePattern):
                    raise AssertionError, (i, item)
                if isinstance(item, WildcardPattern):
                    self.wildcards = True
                    continue
                isinstance(item, BasePattern)


        self.type = type
        self.content = content
        self.name = name


    def _submatch(self, node, results = None):
        """Match the pattern's content to the node's children.

        This assumes the node type matches and self.content is not None.

        Returns True if it matches, False if not.

        If results is not None, it must be a dict which will be
        updated with the nodes matching named subpatterns.

        When returning False, the results dict may still be updated.
        """
        if self.wildcards:
            for c, r in generate_matches(self.content, node.children):
                if c == len(node.children):
                    if results is not None:
                        results.update(r)

                    return True

            return False
        if len(self.content) != len(node.children):
            return False
        for subpattern, child in zip(self.content, node.children):
            if not subpattern.match(child, results):
                return False

        return True



class WildcardPattern(BasePattern):
    '''A wildcard pattern can match zero or more nodes.

    This has all the flexibility needed to implement patterns like:

    .*      .+      .?      .{m,n}
    (a b c | d e | f)
    (...)*  (...)+  (...)?  (...){m,n}

    except it always uses non-greedy matching.
    '''

    def __init__(self, content = None, min = 0, max = HUGE, name = None):
        """Initializer.

        Args:
            content: optional sequence of subsequences of patterns;
                     if absent, matches one node;
                     if present, each subsequence is an alternative [*]
            min: optinal minumum number of times to match, default 0
            max: optional maximum number of times tro match, default HUGE
            name: optional name assigned to this match

        [*] Thus, if content is [[a, b, c], [d, e], [f, g, h]] this is
            equivalent to (a b c | d e | f g h); if content is None,
            this is equivalent to '.' in regular expression terms.
            The min and max parameters work as follows:
                min=0, max=maxint: .*
                min=1, max=maxint: .+
                min=0, max=1: .?
                min=1, max=1: .
            If content is not None, replace the dot with the parenthesized
            list of alternatives, e.g. (a b c | d e | f g h)*
        """
        if min <= min and max <= max:
            pass
        elif not max <= HUGE:
            raise AssertionError, (min, max)
        self.content = content
        self.min = min
        self.max = max
        self.name = name


    def optimize(self):
        '''Optimize certain stacked wildcard patterns.'''
        subpattern = None
        if self.content is not None and len(self.content) == 1 and len(self.content[0]) == 1:
            subpattern = self.content[0][0]

        if self.min <= 1 and isinstance(subpattern, WildcardPattern) and subpattern.min <= 1 and self.name == subpattern.name:
            return WildcardPattern(subpattern.content, self.min * subpattern.min, self.max * subpattern.max, subpattern.name)
        return self


    def match(self, node, results = None):
        '''Does this pattern exactly match a node?'''
        return self.match_seq([
            node], results)


    def match_seq(self, nodes, results = None):
        '''Does this pattern exactly match a sequence of nodes?'''
        for c, r in self.generate_matches(nodes):
            if c == len(nodes):
                if results is not None:
                    results.update(r)
                    if self.name:
                        results[self.name] = list(nodes)


                return True

        return False


    def generate_matches(self, nodes):
        '''Generator yielding matches for a sequence of nodes.

        Args:
            nodes: sequence of nodes

        Yields:
            (count, results) tuples where:
            count: the match comprises nodes[:count];
            results: dict containing named submatches.
        '''
        if self.content is None:
            for count in xrange(self.min, 1 + min(len(nodes), self.max)):
                r = { }
                if self.name:
                    r[self.name] = nodes[:count]

                yield (count, r)

        elif self.name == 'bare_name':
            yield self._bare_name_matches(nodes)
        else:
            save_stderr = sys.stderr
            sys.stderr = StringIO()

            try:
                for count, r in self._recursive_matches(nodes, 0):
                    if self.name:
                        r[self.name] = nodes[:count]

                    yield (count, r)
            except RuntimeError:
                for count, r in self._iterative_matches(nodes):
                    if self.name:
                        r[self.name] = nodes[:count]

                    yield (count, r)

            finally:
                sys.stderr = save_stderr



    def _iterative_matches(self, nodes):
        '''Helper to iteratively yield the matches.'''
        nodelen = len(nodes)
        if 0 >= self.min:
            yield (0, { })

        results = []
        for alt in self.content:
            for c, r in generate_matches(alt, nodes):
                yield (c, r)
                results.append((c, r))


        while results:
            new_results = []
            for c0, r0 in results:
                if c0 < nodelen and c0 <= self.max:
                    for alt in self.content:
                        for c1, r1 in generate_matches(alt, nodes[c0:]):
                            if c1 > 0:
                                r = { }
                                r.update(r0)
                                r.update(r1)
                                yield (c0 + c1, r)
                                new_results.append((c0 + c1, r))
                                continue



            results = new_results


    def _bare_name_matches(self, nodes):
        '''Special optimized matcher for bare_name.'''
        count = 0
        r = { }
        done = False
        max = len(nodes)
        while not done and count < max:
            done = True
            for leaf in self.content:
                if leaf[0].match(nodes[count], r):
                    count += 1
                    done = False
                    break
                    continue

        r[self.name] = nodes[:count]
        return (count, r)


    def _recursive_matches(self, nodes, count):
        '''Helper to recursively yield the matches.'''
        if not self.content is not None:
            raise AssertionError
        if count < self.max:
            for alt in self.content:
                for c0, r0 in generate_matches(alt, nodes):
                    for c1, r1 in self._recursive_matches(nodes[c0:], count + 1):
                        r = { }
                        r.update(r0)
                        r.update(r1)
                        yield (c0 + c1, r)
                        None if count >= self.min else self.content is not None







class NegatedPattern(BasePattern):

    def __init__(self, content = None):
        """Initializer.

        The argument is either a pattern or None.  If it is None, this
        only matches an empty sequence (effectively '$' in regex
        lingo).  If it is not None, this matches whenever the argument
        pattern doesn't have any matches.
        """
        if content is not None:
            if not isinstance(content, BasePattern):
                raise AssertionError, repr(content)

        self.content = content


    def match(self, node):
        return False


    def match_seq(self, nodes):
        return len(nodes) == 0


    def generate_matches(self, nodes):
        if self.content is None:
            if len(nodes) == 0:
                yield (0, { })

        else:
            for c, r in self.content.generate_matches(nodes):
                return None

            yield (0, { })



def generate_matches(patterns, nodes):
    '''Generator yielding matches for a sequence of patterns and nodes.

    Args:
        patterns: a sequence of patterns
        nodes: a sequence of nodes

    Yields:
        (count, results) tuples where:
        count: the entire sequence of patterns matches nodes[:count];
        results: dict containing named submatches.
        '''
    if not patterns:
        yield (0, { })
    else:
        p = patterns[0]
        rest = patterns[1:]
        for c0, r0 in p.generate_matches(nodes):
            if not rest:
                yield (c0, r0)
                continue
            for c1, r1 in generate_matches(rest, nodes[c0:]):
                r = { }
                r.update(r0)
                r.update(r1)
                yield (c0 + c1, r)