def number(self, text):
"""number = ["-"] . ("0" | digit - "0" . {digit}) . ["." . digit +] ;"""
self._attempting(text)
return concatenation([
option(
"-"
),
alternation([
"0",
concatenation([
exclusion(
self.digit,
"0"
),
zero_or_more(
self.digit,
ignore_whitespace=False
),
], ignore_whitespace=False),
]),
option(
concatenation([
".",
one_or_more(
self.digit,
ignore_whitespace=False
),
], ignore_whitespace=False)
),
], ignore_whitespace=False)(text).compressed(TokenType.number)
def return_statement(self, text):
"""return_statement = ["return"] , expression , [";"] ;"""
self._attempting(text)
return concatenation([
option(
"return"
),
self.expression,
option(
";"
),
], ignore_whitespace=True)(text).retyped(TokenType.return_statement)
def test_optional_repetition(self):
# Makes sure nested repetitions will terminate.
c0 = P.zero_or_more(P.option(P.alternation(["a", "b"])))
t0 = "ababaabbaaab"
n0 = c0(t0)
self.assertEqual(n0.consumed, len(t0))
def expression(self, text):
"""expression = number , op_mult , expression
| expression_terminal , op_mult , number , [operator , expression]
| expression_terminal , op_add , [operator , expression]
| expression_terminal , [operator , expression] ;"""
self._attempting(text)
return alternation([
concatenation([
self.number,
self.op_mult,
self.expression,
], ignore_whitespace=True),
concatenation([
self.expression_terminal,
self.op_mult,
self.number,
option(
concatenation([
self.operator,
self.expression,
], ignore_whitespace=True)
),
], ignore_whitespace=True),
concatenation([
self.expression_terminal,
self.op_add,
option(
concatenation([
self.operator,
self.expression,
], ignore_whitespace=True)
),
], ignore_whitespace=True),
concatenation([
self.expression_terminal,
option(
concatenation([
self.operator,
self.expression,
], ignore_whitespace=True)
),
], ignore_whitespace=True),
])(text).retyped(TokenType.expression)
def test_option(self):
c0 = P.option("a")
n0 = c0("a")
self.assertEqual(n0.node_type, P.ParseNodeType.repetition)
self.assertEqual(len(n0.children), 1)
self.assertEqual(n0.children[0].value, "a")
self.assertFalse(n0.is_empty)
n1 = c0("b")
self.assertEqual(n1.node_type, P.ParseNodeType.repetition)
self.assertTrue(n1.is_empty)
def function_call(self, text):
"""function_call = function_name . "(" , [function_args] , ")" ;"""
self._attempting(text)
return concatenation([
self.function_name,
concatenation([
"(",
option(
self.function_args
),
")",
], ignore_whitespace=True),
], ignore_whitespace=False)(text).retyped(TokenType.function_call)
def switch(self, text):
"""switch = switch_subject , switch_case + , [switch_default] ;
s"""
self._attempting(text)
return concatenation([
self.switch_subject,
one_or_more(
self.switch_case,
ignore_whitespace=True
),
option(
self.switch_default
),
], ignore_whitespace=True)(text).retyped(TokenType.switch)