class GParser:
def __init__(self, gramma):
self.gl = Glex(open(gramma).read())
self.lexer = Lexer()
self.classes = []
self.rules = {}
def gnt(self):
self.nt = self.gl.nextToken()
def tis(self, t, v=None):
if not self.nt:
return False
return self.nt[0] == t and (not v or self.nt[1] == v)
def tass(self, t, v=None):
if self.tis(t, v):
return
if v:
raise ParseError("Expected '%s'" % v, self.nt)
else:
raise ParseError("Expected %s" % t, self.nt)
def parseType(self):
self.tass(TLIT) # Name
t = GType(self.nt)
self.gnt()
if self.tis(KEYWORD, "["): # In an array
self.gnt()
self.tass(KEYWORD, "]")
t.isArray = True
self.gnt()
return t
def parseExpr(self):
if self.tis(TLIT):
c = GConstructorCall(self.nt)
self.gnt()
self.tass(KEYWORD, "(")
self.gnt()
if not self.tis(KEYWORD, ")"):
while True:
c.arguments.append(self.parseExpr())
if not self.tis(KEYWORD, ","):
break
self.gnt()
self.tass(KEYWORD, ")")
self.gnt()
return c
if self.tis(KEYWORD, "this"):
x = GThislookup(self.nt)
else:
self.tass(GLIT)
x = GVarlookup(self.nt)
self.gnt()
while True:
if not self.tis(KEYWORD, "."):
break
self.gnt()
self.tass(GLIT)
x = GClasslookup(x, self.nt)
self.gnt()
return x
def parseBlock(self):
b = GBlock()
while True:
if self.tis(KEYWORD, "var"):
v = GVar()
self.gnt()
self.tass(GLIT)
v.name = self.nt
self.gnt()
self.tass(KEYWORD, ":")
self.gnt()
self.tass(TLIT)
v.type = self.nt
self.gnt()
self.tass(KEYWORD, ";")
self.gnt()
b.stmts.append(v)
continue
if self.tis(KEYWORD, "return"):
self.gnt()
b.stmts.append(GReturn(self.parseExpr()))
self.tass(KEYWORD, ";")
self.gnt()
continue
if not self.tis(GLIT) and not self.tis(TLIT) and not self.tis(KEYWORD, "this"):
break
e = self.parseExpr()
if self.tis(KEYWORD, "+="):
self.gnt()
e = GAppend(e, self.parseExpr())
elif self.tis(KEYWORD, "="):
self.gnt()
e = GAssign(e, self.parseExpr())
self.tass(KEYWORD, ";")
self.gnt()
b.stmts.append(e)
return b
def parseClass(self):
self.gnt()
self.tass(TLIT) # Name
c = GClass(self.nt)
self.gnt()
if self.tis(KEYWORD, "("):
self.gnt()
while True:
self.tass(TLIT) # Extend name
c.extends.append(self.nt)
self.gnt()
if not self.tis(KEYWORD, ","):
break
self.gnt()
self.tass(KEYWORD, ")")
self.gnt()
self.tass(KEYWORD, "{")
self.gnt()
while True:
if self.tis(KEYWORD, "construct"):
con = GConstructor()
self.gnt()
self.tass(KEYWORD, "(")
self.gnt()
if not self.tis(KEYWORD, ")"):
while True:
self.tass(GLIT) # Name
n = self.nt
self.gnt()
self.tass(KEYWORD, ":")
self.gnt()
t = self.parseType()
con.arguments.append((n, t))
if not self.tis(KEYWORD, ","):
break
self.gnt()
self.tass(KEYWORD, ")")
self.gnt()
self.tass(KEYWORD, "{")
self.gnt()
con.block = self.parseBlock()
self.tass(KEYWORD, "}")
self.gnt()
c.constructors.append(con)
elif self.tis(KEYWORD, "var"):
self.gnt()
self.tis(GLIT)
n = self.nt
self.gnt()
self.tass(KEYWORD, ":")
self.gnt()
ty = self.parseType()
self.tass(KEYWORD, ";")
self.gnt()
c.vardecls.append(GClassVarDecl(n, ty))
else:
break
self.tass(KEYWORD, "}")
self.gnt()
return c
def parseContinuation(self):
r = GContinuation()
while True:
if self.tis(KEYWORD, "{"):
self.gnt()
r.items.append(self.parseBlock())
self.tass(KEYWORD, "}")
self.gnt()
continue
x = None
if self.tis(KEYWORD, "("):
self.gnt()
x = self.parseConjunction()
self.tass(KEYWORD, ")")
self.gnt()
else:
if self.tis(SLIT):
x = GTokenRef(self.nt)
v = self.nt[1][1:-1]
x.tname = self.lexer.addKeyword(v)
x.displayName = "'%s'" % v
self.gnt()
elif self.tis(TLIT):
x = GTokenRef(self.nt)
self.gnt()
if self.tis(KEYWORD, "["):
self.gnt()
if self.tis(SLIT):
x.displayName = self.nt[1][1:-1]
else:
x.displayName = self.nt[1]
self.gnt()
self.tass(KEYWORD, "]")
self.gnt()
elif self.tis(KEYWORD, "recover"):
self.gnt()
self.tass(TLIT)
x = GTokenRef(self.nt, True)
self.gnt()
elif self.tis(GLIT):
x = GGrammaRef(self.nt)
self.gnt()
else:
break
if self.tis(KEYWORD, ":"):
self.gnt()
self.tass(GLIT)
x.name = self.nt
self.gnt()
if self.tis(KEYWORD, "*"):
x = GStar(x)
self.gnt()
if self.tis(KEYWORD, "*"):
x.captureAll = True
self.gnt()
elif self.tis(KEYWORD, "+"):
x = GPlus(x)
self.gnt()
elif self.tis(KEYWORD, "?"):
x = GOpt(x)
self.gnt()
r.items.append(x)
return r
def parseConjunction(self):
r = self.parseContinuation()
if self.tis(KEYWORD, "|"):
c = GConjunction()
c.items.append(r)
r = c
while self.tis(KEYWORD, "|"):
self.gnt()
r.items.append(self.parseContinuation())
return r
def parse(self):
try:
self.gnt()
while self.nt:
if self.tis(TLIT):
v = self.nt[1]
self.gnt()
self.tass(KEYWORD, ":=")
r = self.gl.nextRegexp()
self.lexer.addClass(v, r)
self.gnt()
continue
if self.tis(KEYWORD, "class"):
self.classes.append(self.parseClass())
continue
self.tass(GLIT)
v = self.nt
self.gnt()
self.tass(KEYWORD, ":=")
self.gnt()
self.rules[v[1]] = (v, self.parseConjunction())
self.tass(KEYWORD, ";")
self.gnt()
except ParseError, e:
print "ParseError: %s\nat %s" % (e.msg, self.gl.tloc(e.tok))
