def parse(self, text):
self.lexer = Lexer(text)
self.tokens = Peep([t for t in self.lexer.next_token()])
ast = Steps()
retval = self.instruction()
assert retval and retval.instruction == "FROM"
while retval: # read instructions
if type(retval) != bool:
ast.steps.append(retval)
retval = self.instruction()
return ast
class Parser(object):
def expect(self, *a, **kw):
t, _ = self.tokens.peak()
if t == "EOF":
return False
if t in list(a) + [v for k, v in kw.iteritems()]:
self.tokens.next()
return True
return False
def expect_not(self, *a, **kw):
t, _ = self.tokens.peak()
if t == "EOF":
return False
if t not in list(a) + [v for k, v in kw.iteritems()]:
self.tokens.next()
return True
return False
def must(self, *a, **kw):
t, _ = self.tokens.peak()
if t in list(a) + [v for k, v in kw.iteritems()]:
self.tokens.next()
return True
raise Exception(
"Expected {}, but got {}".format(
",".join(list(a) + [v for k, v in kw.iteritems()]), t
)
)
def must_be(self, typ, val):
t, v = self.tokens.peak()
if t == typ and v == val:
self.tokens.next()
return True
raise Exception(
"Expected {} ({}), but got {} ({})".format(
val, typ,
v, t,
)
)
def parse(self, text):
self.lexer = Lexer(text)
self.tokens = Peep([t for t in self.lexer.next_token()])
ast = Steps()
retval = self.instruction()
assert retval and retval.instruction == "FROM"
while retval: # read instructions
if type(retval) != bool:
ast.steps.append(retval)
retval = self.instruction()
return ast
def instruction(self):
while self.expect("WHITESPACE"):
pass
if self.expect("NEWLINE"):
return True
step = Step()
if self.expect("COMMENT"):
return True
elif self.expect("KEYWORD"):
step.instruction = self.tokens.last()[1]
self.expect("WHITESPACE")
if step.instruction in KEYWORDS_JSON_SUPPORT \
and self.expect("BRACKET_OPEN"):
# expect json array
self.must("STRING")
step.arguments.append(self.tokens.last()[1])
while self.expect("COMMA"):
self.expect("WHITESPACE")
self.must("STRING")
step.arguments.append(self.tokens.last()[1])
self.expect("WHITESPACE")
self.must("BRACKET_CLOSE")
while self.expect("WHITESPACE"):
pass
self.expect("NEWLINE")
else:
while self.expect_not("NEWLINE"):
if self.tokens.last()[0] == "WHITESPACE": # skip spaces
continue
step.arguments.append(self.tokens.last()[1])
self.expect("NEWLINE")
return step
return False
