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from __future__ import absolute_import, print_function
from unittest import TestCase, main
from lark import Lark
from lark.tree import Tree
from lark.tools import standalone
from io import StringIO
class TestStandalone(TestCase):
def setUp(self):
pass
def _create_standalone(self, grammar, compress=False):
code_buf = StringIO()
standalone.gen_standalone(Lark(grammar, parser='lalr'), out=code_buf, compress=compress)
code = code_buf.getvalue()
context = {'__doc__': None, '__name__': 'test_standalone'}
exec(code, context)
return context
def test_simple(self):
grammar = """
start: NUMBER WORD
%import common.NUMBER
%import common.WORD
%import common.WS
%ignore WS
"""
context = self._create_standalone(grammar)
_Lark = context['Lark_StandAlone']
l = _Lark()
x = l.parse('12 elephants')
self.assertEqual(x.children, ['12', 'elephants'])
x = l.parse('16 candles')
self.assertEqual(x.children, ['16', 'candles'])
self.assertRaises(context['UnexpectedToken'], l.parse, 'twelve monkeys')
self.assertRaises(context['UnexpectedToken'], l.parse, 'twelve')
self.assertRaises(context['UnexpectedCharacters'], l.parse, '$ talks')
context = self._create_standalone(grammar, compress=True)
_Lark = context['Lark_StandAlone']
l = _Lark()
x = l.parse('12 elephants')
def test_interactive(self):
grammar = """
start: A+ B*
A: "a"
B: "b"
"""
context = self._create_standalone(grammar)
parser: Lark = context['Lark_StandAlone']()
ip = parser.parse_interactive()
UnexpectedToken = context['UnexpectedToken']
Token = context['Token']
self.assertRaises(UnexpectedToken, ip.feed_eof)
self.assertRaises(TypeError, ip.exhaust_lexer)
ip.feed_token(Token('A', 'a'))
res = ip.feed_eof()
self.assertEqual(res, Tree('start', ['a']))
ip = parser.parse_interactive("ab")
ip.exhaust_lexer()
ip_copy = ip.copy()
self.assertEqual(ip_copy.parser_state, ip.parser_state)
self.assertEqual(ip_copy.lexer_thread.state, ip.lexer_thread.state)
self.assertIsNot(ip_copy.parser_state, ip.parser_state)
self.assertIsNot(ip_copy.lexer_thread.state, ip.lexer_thread.state)
self.assertIsNot(ip_copy.lexer_thread.state.line_ctr, ip.lexer_thread.state.line_ctr)
res = ip.feed_eof(ip.lexer_thread.state.last_token)
self.assertEqual(res, Tree('start', ['a', 'b']))
self.assertRaises(UnexpectedToken, ip.feed_eof)
self.assertRaises(UnexpectedToken, ip_copy.feed_token, Token('A', 'a'))
ip_copy.feed_token(Token('B', 'b'))
res = ip_copy.feed_eof()
self.assertEqual(res, Tree('start', ['a', 'b', 'b']))
def test_contextual(self):
grammar = """
start: a b
a: "A" "B"
b: "AB"
"""
context = self._create_standalone(grammar)
_Lark = context['Lark_StandAlone']
l = _Lark()
x = l.parse('ABAB')
_v_args = context['v_args']
@_v_args(inline=True)
class T(context['Transformer']):
def a(self):
return 'a'
def b(self):
return 'b'
start = _v_args(inline=False)(list)
x = T().transform(x)
self.assertEqual(x, ['a', 'b'])
l2 = _Lark(transformer=T())
x = l2.parse('ABAB')
self.assertEqual(x, ['a', 'b'])
def test_postlex(self):
from lark.indenter import Indenter
class MyIndenter(Indenter):
NL_type = '_NEWLINE'
OPEN_PAREN_types = ['LPAR', 'LSQB', 'LBRACE']
CLOSE_PAREN_types = ['RPAR', 'RSQB', 'RBRACE']
INDENT_type = '_INDENT'
DEDENT_type = '_DEDENT'
tab_len = 8
grammar = r"""
start: "(" ")" _NEWLINE
_NEWLINE: /\n/
"""
context = self._create_standalone(grammar)
_Lark = context['Lark_StandAlone']
l = _Lark(postlex=MyIndenter())
x = l.parse('()\n')
self.assertEqual(x, Tree('start', []))
l = _Lark(postlex=MyIndenter())
x = l.parse('(\n)\n')
self.assertEqual(x, Tree('start', []))
def test_transformer(self):
grammar = r"""
start: some_rule "(" SOME_TERMINAL ")"
some_rule: SOME_TERMINAL
SOME_TERMINAL: /[A-Za-z_][A-Za-z0-9_]*/
"""
context = self._create_standalone(grammar)
_Lark = context["Lark_StandAlone"]
_Token = context["Token"]
_Tree = context["Tree"]
class MyTransformer(context["Transformer"]):
def SOME_TERMINAL(self, token):
return _Token("SOME_TERMINAL", "token is transformed")
def some_rule(self, children):
return _Tree("rule_is_transformed", [])
parser = _Lark(transformer=MyTransformer())
self.assertEqual(
parser.parse("FOO(BAR)"),
_Tree("start", [
_Tree("rule_is_transformed", []),
_Token("SOME_TERMINAL", "token is transformed")
])
)
if __name__ == '__main__':
main()
|
