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Viewing changes to pypy/rlib/parsing/tree.py

  • Committer: Bazaar Package Importer
  • Author(s): Alexandre Fayolle
  • Date: 2007-04-13 09:33:09 UTC
  • Revision ID: james.westby@ubuntu.com-20070413093309-yoojh4jcoocu2krz
Tags: upstream-1.0.0
Import upstream version 1.0.0

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Lines of Context:
pypy/rlib/parsing/tree.py
 
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import py
 
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class Node(object):
 
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    def view(self):
 
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        from pypy.translator.tool.pygame import graphclient
 
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        content = ["digraph G{"]
 
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        content.extend(self.dot())
 
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        content.append("}")
 
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        p = py.test.ensuretemp("automaton").join("temp.dot")
 
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        p.write("\n".join(content))
 
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        graphclient.display_dot_file(str(p))
 
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class Symbol(Node):
 
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    def __init__(self, symbol, additional_info, token):
 
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        self.symbol = symbol
 
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        self.additional_info = additional_info
 
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        self.token = token
 
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    def __repr__(self):
 
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        return "Symbol(%r, %r)" % (self.symbol, self.additional_info)
 
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    def dot(self):
 
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        addinfo = str(self.additional_info).replace('"', "'") or "_"
 
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        yield ('"%s" [shape=box,label="%s\\n%s"];' % (
 
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            id(self), self.symbol.replace("\\", "\\\\"),
 
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            repr(addinfo).replace('"', '').replace("\\", "\\\\")))
 
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    def visit(self, visitor):
 
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        "NOT_RPYTHON"
 
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        if isinstance(visitor, RPythonVisitor):
 
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            return visitor.dispatch(self)
 
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        method = getattr(visitor, "visit_" + self.symbol, None)
 
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        if method is None:
 
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            return self
 
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        return method(self)
 
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class Nonterminal(Node):
 
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    def __init__(self, symbol, children):
 
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        self.children = children
 
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        self.symbol = symbol
 
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    def __str__(self):
 
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        return "%s(%s)" % (self.symbol, ", ".join([str(c) for c in self.children]))
 
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    def __repr__(self):
 
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        return "Nonterminal(%r, %r)" % (self.symbol, self.children)
 
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    def dot(self):
 
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        yield '"%s" [label="%s"];' % (id(self), self.symbol)
 
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        for child in self.children:
 
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            yield '"%s" -> "%s";' % (id(self), id(child))
 
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            for line in child.dot():
 
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                yield line
 
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    def visit(self, visitor):
 
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        "NOT_RPYTHON"
 
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        if isinstance(visitor, RPythonVisitor):
 
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            visitor.dispatch(self)
 
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        general = getattr(visitor, "visit", None)
 
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        if general is None:
 
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            return getattr(visitor, "visit_" + self.symbol)(self)
 
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        else:
 
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            specific = getattr(visitor, "visit_" + self.symbol, None)
 
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            if specific is None:
 
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                return general(self)
 
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            else:
 
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                return specific(self)
 
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class VisitError(Exception):
 
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    def __init__(self, node):
 
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        self.node = node
 
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        self.args = (node, )
 
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    def __str__(self):
 
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        return "could not visit %s" % (self.node, )
 
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def make_dispatch_function(__general_nonterminal_visit=None,
 
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                           __general_symbol_visit=None,
 
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                           __general_visit=None,
 
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                           **dispatch_table):
 
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    def dispatch(self, node):
 
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        if isinstance(node, Nonterminal):
 
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            if node.symbol not in dispatch_table:
 
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                if __general_nonterminal_visit:
 
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                    return __general_nonterminal_visit(self, node)
 
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                elif __general_visit:
 
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                    return __general_visit(self, node)
 
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                else:
 
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                    raise VisitError(node)
 
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            else:
 
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                return dispatch_table[node.symbol](self, node)
 
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        if isinstance(node, Symbol):
 
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            if node.symbol not in dispatch_table:
 
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                if __general_symbol_visit:
 
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                    return __general_symbol_visit(self, node)
 
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                elif __general_visit:
 
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                    return __general_visit(self, node)
 
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                else:
 
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                    raise VisitError(node)
 
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            else:
 
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                return dispatch_table[node.symbol](self, node)
 
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        raise VisitError(node)
 
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    return dispatch
 
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class CreateDispatchDictionaryMetaclass(type):
 
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    def __new__(cls, name_, bases, dct):
 
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        dispatch_table = {}
 
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        for name, value in dct.iteritems():
 
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            if name.startswith("visit_"):
 
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                dispatch_table[name[len("visit_"):]] = value
 
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        for special in ["general_symbol_visit",
 
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                        "general_nonterminal_visit",
 
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                        "general_visit"]:
 
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            if special in dct:
 
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                dispatch_table["__" + special] = dct[special]
 
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        dct["dispatch"] = make_dispatch_function(**dispatch_table)
 
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        return type.__new__(cls, name_, bases, dct)
 
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class RPythonVisitor(object):
 
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    __metaclass__ = CreateDispatchDictionaryMetaclass