1 files changed, 386 insertions, 0 deletions
diff --git a/lib/python2.7/lib2to3/pgen2/pgen.py b/lib/python2.7/lib2to3/pgen2/pgen.py
new file mode 100644
index 0000000..ed16992
--- /dev/null
+++ b/lib/python2.7/lib2to3/pgen2/pgen.py
@@ -0,0 +1,386 @@
+# Copyright 2004-2005 Elemental Security, Inc. All Rights Reserved.
+# Licensed to PSF under a Contributor Agreement.
+
+# Pgen imports
+from . import grammar, token, tokenize
+
+class PgenGrammar(grammar.Grammar):
+    pass
+
+class ParserGenerator(object):
+
+    def __init__(self, filename, stream=None):
+        close_stream = None
+        if stream is None:
+            stream = open(filename)
+            close_stream = stream.close
+        self.filename = filename
+        self.stream = stream
+        self.generator = tokenize.generate_tokens(stream.readline)
+        self.gettoken() # Initialize lookahead
+        self.dfas, self.startsymbol = self.parse()
+        if close_stream is not None:
+            close_stream()
+        self.first = {} # map from symbol name to set of tokens
+        self.addfirstsets()
+
+    def make_grammar(self):
+        c = PgenGrammar()
+        names = self.dfas.keys()
+        names.sort()
+        names.remove(self.startsymbol)
+        names.insert(0, self.startsymbol)
+        for name in names:
+            i = 256 + len(c.symbol2number)
+            c.symbol2number[name] = i
+            c.number2symbol[i] = name
+        for name in names:
+            dfa = self.dfas[name]
+            states = []
+            for state in dfa:
+                arcs = []
+                for label, next in sorted(state.arcs.iteritems()):
+                    arcs.append((self.make_label(c, label), dfa.index(next)))
+                if state.isfinal:
+                    arcs.append((0, dfa.index(state)))
+                states.append(arcs)
+            c.states.append(states)
+            c.dfas[c.symbol2number[name]] = (states, self.make_first(c, name))
+        c.start = c.symbol2number[self.startsymbol]
+        return c
+
+    def make_first(self, c, name):
+        rawfirst = self.first[name]
+        first = {}
+        for label in sorted(rawfirst):
+            ilabel = self.make_label(c, label)
+            ##assert ilabel not in first # XXX failed on <> ... !=
+            first[ilabel] = 1
+        return first
+
+    def make_label(self, c, label):
+        # XXX Maybe this should be a method on a subclass of converter?
+        ilabel = len(c.labels)
+        if label[0].isalpha():
+            # Either a symbol name or a named token
+            if label in c.symbol2number:
+                # A symbol name (a non-terminal)
+                if label in c.symbol2label:
+                    return c.symbol2label[label]
+                else:
+                    c.labels.append((c.symbol2number[label], None))
+                    c.symbol2label[label] = ilabel
+                    return ilabel
+            else:
+                # A named token (NAME, NUMBER, STRING)
+                itoken = getattr(token, label, None)
+                assert isinstance(itoken, int), label
+                assert itoken in token.tok_name, label
+                if itoken in c.tokens:
+                    return c.tokens[itoken]
+                else:
+                    c.labels.append((itoken, None))
+                    c.tokens[itoken] = ilabel
+                    return ilabel
+        else:
+            # Either a keyword or an operator
+            assert label[0] in ('"', "'"), label
+            value = eval(label)
+            if value[0].isalpha():
+                # A keyword
+                if value in c.keywords:
+                    return c.keywords[value]
+                else:
+                    c.labels.append((token.NAME, value))
+                    c.keywords[value] = ilabel
+                    return ilabel
+            else:
+                # An operator (any non-numeric token)
+                itoken = grammar.opmap[value] # Fails if unknown token
+                if itoken in c.tokens:
+                    return c.tokens[itoken]
+                else:
+                    c.labels.append((itoken, None))
+                    c.tokens[itoken] = ilabel
+                    return ilabel
+
+    def addfirstsets(self):
+        names = self.dfas.keys()
+        names.sort()
+        for name in names:
+            if name not in self.first:
+                self.calcfirst(name)
+            #print name, self.first[name].keys()
+
+    def calcfirst(self, name):
+        dfa = self.dfas[name]
+        self.first[name] = None # dummy to detect left recursion
+        state = dfa[0]
+        totalset = {}
+        overlapcheck = {}
+        for label, next in state.arcs.iteritems():
+            if label in self.dfas:
+                if label in self.first:
+                    fset = self.first[label]
+                    if fset is None:
+                        raise ValueError("recursion for rule %r" % name)
+                else:
+                    self.calcfirst(label)
+                    fset = self.first[label]
+                totalset.update(fset)
+                overlapcheck[label] = fset
+            else:
+                totalset[label] = 1
+                overlapcheck[label] = {label: 1}
+        inverse = {}
+        for label, itsfirst in overlapcheck.iteritems():
+            for symbol in itsfirst:
+                if symbol in inverse:
+                    raise ValueError("rule %s is ambiguous; %s is in the"
+                                     " first sets of %s as well as %s" %
+                                     (name, symbol, label, inverse[symbol]))
+                inverse[symbol] = label
+        self.first[name] = totalset
+
+    def parse(self):
+        dfas = {}
+        startsymbol = None
+        # MSTART: (NEWLINE | RULE)* ENDMARKER
+        while self.type != token.ENDMARKER:
+            while self.type == token.NEWLINE:
+                self.gettoken()
+            # RULE: NAME ':' RHS NEWLINE
+            name = self.expect(token.NAME)
+            self.expect(token.OP, ":")
+            a, z = self.parse_rhs()
+            self.expect(token.NEWLINE)
+            #self.dump_nfa(name, a, z)
+            dfa = self.make_dfa(a, z)
+            #self.dump_dfa(name, dfa)
+            oldlen = len(dfa)
+            self.simplify_dfa(dfa)
+            newlen = len(dfa)
+            dfas[name] = dfa
+            #print name, oldlen, newlen
+            if startsymbol is None:
+                startsymbol = name
+        return dfas, startsymbol
+
+    def make_dfa(self, start, finish):
+        # To turn an NFA into a DFA, we define the states of the DFA
+        # to correspond to *sets* of states of the NFA.  Then do some
+        # state reduction.  Let's represent sets as dicts with 1 for
+        # values.
+        assert isinstance(start, NFAState)
+        assert isinstance(finish, NFAState)
+        def closure(state):
+            base = {}
+            addclosure(state, base)
+            return base
+        def addclosure(state, base):
+            assert isinstance(state, NFAState)
+            if state in base:
+                return
+            base[state] = 1
+            for label, next in state.arcs:
+                if label is None:
+                    addclosure(next, base)
+        states = [DFAState(closure(start), finish)]
+        for state in states: # NB states grows while we're iterating
+            arcs = {}
+            for nfastate in state.nfaset:
+                for label, next in nfastate.arcs:
+                    if label is not None:
+                        addclosure(next, arcs.setdefault(label, {}))
+            for label, nfaset in sorted(arcs.iteritems()):
+                for st in states:
+                    if st.nfaset == nfaset:
+                        break
+                else:
+                    st = DFAState(nfaset, finish)
+                    states.append(st)
+                state.addarc(st, label)
+        return states # List of DFAState instances; first one is start
+
+    def dump_nfa(self, name, start, finish):
+        print "Dump of NFA for", name
+        todo = [start]
+        for i, state in enumerate(todo):
+            print "  State", i, state is finish and "(final)" or ""
+            for label, next in state.arcs:
+                if next in todo:
+                    j = todo.index(next)
+                else:
+                    j = len(todo)
+                    todo.append(next)
+                if label is None:
+                    print "    -> %d" % j
+                else:
+                    print "    %s -> %d" % (label, j)
+
+    def dump_dfa(self, name, dfa):
+        print "Dump of DFA for", name
+        for i, state in enumerate(dfa):
+            print "  State", i, state.isfinal and "(final)" or ""
+            for label, next in sorted(state.arcs.iteritems()):
+                print "    %s -> %d" % (label, dfa.index(next))
+
+    def simplify_dfa(self, dfa):
+        # This is not theoretically optimal, but works well enough.
+        # Algorithm: repeatedly look for two states that have the same
+        # set of arcs (same labels pointing to the same nodes) and
+        # unify them, until things stop changing.
+
+        # dfa is a list of DFAState instances
+        changes = True
+        while changes:
+            changes = False
+            for i, state_i in enumerate(dfa):
+                for j in range(i+1, len(dfa)):
+                    state_j = dfa[j]
+                    if state_i == state_j:
+                        #print "  unify", i, j
+                        del dfa[j]
+                        for state in dfa:
+                            state.unifystate(state_j, state_i)
+                        changes = True
+                        break
+
+    def parse_rhs(self):
+        # RHS: ALT ('|' ALT)*
+        a, z = self.parse_alt()
+        if self.value != "|":
+            return a, z
+        else:
+            aa = NFAState()
+            zz = NFAState()
+            aa.addarc(a)
+            z.addarc(zz)
+            while self.value == "|":
+                self.gettoken()
+                a, z = self.parse_alt()
+                aa.addarc(a)
+                z.addarc(zz)
+            return aa, zz
+
+    def parse_alt(self):
+        # ALT: ITEM+
+        a, b = self.parse_item()
+        while (self.value in ("(", "[") or
+               self.type in (token.NAME, token.STRING)):
+            c, d = self.parse_item()
+            b.addarc(c)
+            b = d
+        return a, b
+
+    def parse_item(self):
+        # ITEM: '[' RHS ']' | ATOM ['+' | '*']
+        if self.value == "[":
+            self.gettoken()
+            a, z = self.parse_rhs()
+            self.expect(token.OP, "]")
+            a.addarc(z)
+            return a, z
+        else:
+            a, z = self.parse_atom()
+            value = self.value
+            if value not in ("+", "*"):
+                return a, z
+            self.gettoken()
+            z.addarc(a)
+            if value == "+":
+                return a, z
+            else:
+                return a, a
+
+    def parse_atom(self):
+        # ATOM: '(' RHS ')' | NAME | STRING
+        if self.value == "(":
+            self.gettoken()
+            a, z = self.parse_rhs()
+            self.expect(token.OP, ")")
+            return a, z
+        elif self.type in (token.NAME, token.STRING):
+            a = NFAState()
+            z = NFAState()
+            a.addarc(z, self.value)
+            self.gettoken()
+            return a, z
+        else:
+            self.raise_error("expected (...) or NAME or STRING, got %s/%s",
+                             self.type, self.value)
+
+    def expect(self, type, value=None):
+        if self.type != type or (value is not None and self.value != value):
+            self.raise_error("expected %s/%s, got %s/%s",
+                             type, value, self.type, self.value)
+        value = self.value
+        self.gettoken()
+        return value
+
+    def gettoken(self):
+        tup = self.generator.next()
+        while tup[0] in (tokenize.COMMENT, tokenize.NL):
+            tup = self.generator.next()
+        self.type, self.value, self.begin, self.end, self.line = tup
+        #print token.tok_name[self.type], repr(self.value)
+
+    def raise_error(self, msg, *args):
+        if args:
+            try:
+                msg = msg % args
+            except:
+                msg = " ".join([msg] + map(str, args))
+        raise SyntaxError(msg, (self.filename, self.end[0],
+                                self.end[1], self.line))
+
+class NFAState(object):
+
+    def __init__(self):
+        self.arcs = [] # list of (label, NFAState) pairs
+
+    def addarc(self, next, label=None):
+        assert label is None or isinstance(label, str)
+        assert isinstance(next, NFAState)
+        self.arcs.append((label, next))
+
+class DFAState(object):
+
+    def __init__(self, nfaset, final):
+        assert isinstance(nfaset, dict)
+        assert isinstance(iter(nfaset).next(), NFAState)
+        assert isinstance(final, NFAState)
+        self.nfaset = nfaset
+        self.isfinal = final in nfaset
+        self.arcs = {} # map from label to DFAState
+
+    def addarc(self, next, label):
+        assert isinstance(label, str)
+        assert label not in self.arcs
+        assert isinstance(next, DFAState)
+        self.arcs[label] = next
+
+    def unifystate(self, old, new):
+        for label, next in self.arcs.iteritems():
+            if next is old:
+                self.arcs[label] = new
+
+    def __eq__(self, other):
+        # Equality test -- ignore the nfaset instance variable
+        assert isinstance(other, DFAState)
+        if self.isfinal != other.isfinal:
+            return False
+        # Can't just return self.arcs == other.arcs, because that
+        # would invoke this method recursively, with cycles...
+        if len(self.arcs) != len(other.arcs):
+            return False
+        for label, next in self.arcs.iteritems():
+            if next is not other.arcs.get(label):
+                return False
+        return True
+
+    __hash__ = None # For Py3 compatibility.
+
+def generate_grammar(filename="Grammar.txt"):
+    p = ParserGenerator(filename)
+    return p.make_grammar()