def TokenFactor(self):
g = None
if self.la.kind == Scanner.ident_Sym or self.la.kind == Scanner.string_Sym:
s = self.Sym()
name, kind = s
if kind == self.id:
c = CharClass.Find(name)
if c is None:
self.SemErr("undefined name")
c = CharClass(s.name, set())
p = Node(Node.clas, None, 0)
p.val = c.n
g = Graph(p)
self.tokenString = self.noString
else: # str
g = Graph.StrToGraph(name)
if self.tokenString is None:
self.tokenString = name
else:
self.tokenString = self.noString
elif self.la.kind == Scanner.lparen_Sym:
self.Get()
g = self.TokenExpr()
self.Expect(Scanner.rparen_Sym)
elif self.la.kind == Scanner.lbrack_Sym:
self.Get()
g = self.TokenExpr()
self.Expect(Scanner.rbrack_Sym)
Graph.MakeOption(g)
elif self.la.kind == Scanner.lbrace_Sym:
self.Get()
g = self.TokenExpr()
self.Expect(Scanner.rbrace_Sym)
Graph.MakeIteration(g)
else:
self.SynErr(76)
if g is None: # invalid start of TokenFactor
g = Graph(Node(Node.eps, None, 0))
return g
def Factor(self):
weak = False
g = None
if self.la.kind == Scanner.ident_Sym or self.la.kind == Scanner.string_Sym or self.la.kind == Scanner.WEAK_Sym:
if (self.la.kind == Scanner.WEAK_Sym):
self.Get()
weak = True
s = self.Sym()
name, kind = s
sym = Symbol.Find(name)
if (sym is None) and (kind == self.str):
sym = Tab.literals.get(name)
undef = (sym is None)
if undef:
if kind == self.id:
sym = Symbol(Node.nt, name, 0) # forward nt
elif self.genScanner:
sym = Symbol(Node.t, name, self.token.line)
DFA.MatchLiteral(sym.name, sym)
else: # undefined string in production
self.SemErr("undefined string in production")
sym = Tab.eofSy # dummy
typ = sym.typ
if (typ != Node.t) and (typ != Node.nt):
self.SemErr("this symbol kind is not allowed in a production")
if weak:
if typ == Node.t:
typ = Node.wt
else:
self.SemErr("only terminals may be weak")
p = Node(typ, sym, self.token.line)
g = Graph(p)
if (self.la.kind == Scanner.less_Sym
or self.la.kind == Scanner.lesspoint_Sym):
self.Attribs(p)
if kind != self.id:
self.SemErr("a literal must not have attributes")
if undef:
sym.attrPos = p.pos # dummy
sym.retVar = p.retVar # AH - dummy
elif ((p.pos is None) !=
(sym.attrPos is None)) or ((p.retVar is None) !=
(sym.retVar is None)):
self.SemErr(
"attribute mismatch between declaration and use of this symbol"
)
elif self.la.kind == Scanner.lparen_Sym:
self.Get()
g = self.Expression()
self.Expect(Scanner.rparen_Sym)
elif self.la.kind == Scanner.lbrack_Sym:
self.Get()
g = self.Expression()
self.Expect(Scanner.rbrack_Sym)
Graph.MakeOption(g)
elif self.la.kind == Scanner.lbrace_Sym:
self.Get()
g = self.Expression()
self.Expect(Scanner.rbrace_Sym)
Graph.MakeIteration(g)
elif self.la.kind == Scanner.lparenpoint_Sym:
pos = self.SemText()
p = Node(Node.sem, None, 0)
p.pos = pos
g = Graph(p)
elif self.la.kind == Scanner.ANY_Sym:
self.Get()
p = Node(Node.any, None, 0) # p.set is set in Tab.SetupAnys
g = Graph(p)
elif self.la.kind == Scanner.SYNC_Sym:
self.Get()
p = Node(Node.sync, None, 0)
g = Graph(p)
else:
self.SynErr(68)
if g is None: # invalid start of Factor
g = Graph(Node(Node.eps, None, 0))
return g