def terminal(self, text):
"""terminal = '"' . (printable - '"') + . '"'
| "'" . (printable - "'") + . "'" ;"""
self._attempting(text)
return alternation([
concatenation([
'"',
one_or_more(
exclusion(
self.printable,
'"'
),
ignore_whitespace=False
),
'"',
], ignore_whitespace=False),
concatenation([
"'",
one_or_more(
exclusion(
self.printable,
"'"
),
ignore_whitespace=False
),
"'",
], ignore_whitespace=False),
])(text).compressed(TokenType.terminal)
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 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 identifier(self, text):
"""identifier = simple_identifier | complex_identifier ;"""
self._attempting(text)
return alternation([
self.simple_identifier,
self.complex_identifier,
])(text).retyped(TokenType.identifier)
def identifier(self, text):
"""identifier = (alpha_character | "_") . {alpha_character | "_" | digit} ;"""
self._attempting(text)
return concatenation([
alternation([
self.alpha_character,
"_",
]),
zero_or_more(
alternation([
self.alpha_character,
"_",
self.digit,
]),
ignore_whitespace=False
),
], ignore_whitespace=False)(text).compressed(TokenType.identifier)
def operator(self, text):
"""operator = "|" | "." | "," | "-" ;"""
self._attempting(text)
return alternation([
"|",
".",
",",
"-",
])(text).retyped(TokenType.operator)
def simple_identifier(self, text):
"""simple_identifier = (alpha_character | "_") . {alpha_character | digit | "_" | "."} ;"""
self._attempting(text)
return concatenation([
alternation([
self.alpha_character,
"_",
]),
zero_or_more(
alternation([
self.alpha_character,
self.digit,
"_",
".",
]),
ignore_whitespace=False
),
], ignore_whitespace=False)(text).retyped(TokenType.simple_identifier)
def test_alternation(self):
c0 = P.alternation(["a", "b", "c", "a("])
self.assertEqual(c0("agh").value, "a")
self.assertEqual(c0("b(").value, "b")
self.assertEqual(c0("c_-").value, "c")
self.assertEqual(c0("a(b, c)").value, "a(")
with self.assertRaises(P.DeadEnd):
c0("d")
def statement(self, text):
"""statement = comment | assignment , ";" ;"""
self._attempting(text)
return alternation([
self.comment,
concatenation([
self.assignment,
";",
], ignore_whitespace=True),
])(text)
def reserved_words(self, text):
"""reserved_words = "return" | "if" | "elif" | "else" | "switch" | "when";"""
self._attempting(text)
return alternation([
"return",
"if",
"elif",
"else",
"switch",
"when",
])(text).retyped(TokenType.reserved_words)
def assignment(self, text):
"""assignment = variable , (":=" | "<-") , expression ;"""
self._attempting(text)
return concatenation([
self.variable,
alternation([
":=",
"<-",
]),
self.expression,
], ignore_whitespace=True)(text).retyped(TokenType.assignment)
def test_exclusion(self):
c0 = P.alternation(["a", "b"])
c1 = P.exclusion(c0, "b")
n0 = c1("a")
self.assertEqual(n0.node_type, P.ParseNodeType.terminal)
self.assertEqual(n0.value, "a")
self.assertEqual(c0("b").value, "b")
with self.assertRaises(P.DeadEnd):
c1("ba")
def expression_terminal(self, text):
"""expression_terminal = identifier
| terminal
| option_group
| repetition_group
| grouping_group
| special_handling ;"""
self._attempting(text)
return alternation([
self.identifier,
self.terminal,
self.option_group,
self.repetition_group,
self.grouping_group,
self.special_handling,
])(text)
def grammar(self, text):
"""grammar = {comment} , rule , {comment | rule} ;"""
self._attempting(text)
return concatenation([
zero_or_more(
self.comment,
ignore_whitespace=True
),
self.rule,
zero_or_more(
alternation([
self.comment,
self.rule,
]),
ignore_whitespace=True
),
], ignore_whitespace=True)(text).retyped(TokenType.grammar)
def expression_terminal(self, text):
"""expression_terminal = number
| string
| variable
| subexpression
| function_call
| branch
| switch ;"""
self._attempting(text)
return alternation([
self.number,
self.string,
self.variable,
self.subexpression,
self.function_call,
self.branch,
self.switch,
])(text)
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 single_string_char(self, text):
"""single_string_char = "\\" . all_characters - "'"
| "\" . "'"
| all_characters - "'" ;"""
self._attempting(text)
return alternation([
concatenation([
"\\\\",
exclusion(
self.all_characters,
"'"
),
], ignore_whitespace=False),
concatenation([
"\\",
"'",
], ignore_whitespace=False),
exclusion(
self.all_characters,
"'"
),
])(text).retyped(TokenType.single_string_char)
def double_string_char(self, text):
"""double_string_char = "\\" . all_characters - '"'
| "\" . '"'
| all_characters - '"' ;"""
self._attempting(text)
return alternation([
concatenation([
"\\\\",
exclusion(
self.all_characters,
'"'
),
], ignore_whitespace=False),
concatenation([
"\\",
'"',
], ignore_whitespace=False),
exclusion(
self.all_characters,
'"'
),
])(text).retyped(TokenType.double_string_char)
def string(self, text):
"""string = '"' . {double_string_char} . '"'
| "'" . {single_string_char} . "'" ;"""
self._attempting(text)
return alternation([
concatenation([
'"',
zero_or_more(
self.double_string_char,
ignore_whitespace=False
),
'"',
], ignore_whitespace=False),
concatenation([
"'",
zero_or_more(
self.single_string_char,
ignore_whitespace=False
),
"'",
], ignore_whitespace=False),
])(text).compressed(TokenType.string)
def comment(self, text):
"""comment = "/*" . {all_characters - "*" | "*" . all_characters - "/"} . "*/" ;"""
self._attempting(text)
return concatenation([
"/*",
zero_or_more(
alternation([
exclusion(
self.all_characters,
"*"
),
concatenation([
"*",
exclusion(
self.all_characters,
"/"
),
], ignore_whitespace=False),
]),
ignore_whitespace=False
),
"*/",
], ignore_whitespace=False)(text).compressed(TokenType.comment)
def operator(self, text):
"""operator = "+" | "-" | "*" | "/" | "%" | "^"
| "=" | "!=" | ">=" | "<=" | ">" | "<"
| "!" | "|" | "&" | "?" ;"""
self._attempting(text)
return alternation([
"+",
"-",
"*",
"/",
"%",
"^",
"=",
"!=",
">=",
"<=",
">",
"<",
"!",
"|",
"&",
"?",
])(text).retyped(TokenType.operator)
def comment(self, text):
"""comment = "(*" . {printable - "*" | "*" . printable - ")"} . "*)" ;"""
self._attempting(text)
return concatenation([
"(*",
zero_or_more(
alternation([
exclusion(
self.printable,
"*"
),
concatenation([
"*",
exclusion(
self.printable,
")"
),
], ignore_whitespace=False),
]),
ignore_whitespace=False
),
"*)",
], ignore_whitespace=False)(text).compressed(TokenType.comment)