def test_maybe_2():
program = ("start: [foo]\n" "foo: NAME\n")
rules = start(program).rules
assert rules == [
Rule('start', [Alt([Maybe('foo')])]),
Rule('foo', [Alt(['NAME'])])
]
def test_grammar():
program = ("stmt: asmt | expr\n" "asmt: NAME '=' expr\n" "expr: NAME\n")
rules = start(program).rules
assert rules == [
Rule('stmt', [Alt(['asmt']), Alt(['expr'])]),
Rule('asmt', [Alt(['NAME', "'='", 'expr'])]),
Rule('expr', [Alt(['NAME'])])
]
def test_maybe_3():
program = ("start: [foo foo | foo]\n" "foo: NAME\n")
rules = start(program).rules
assert rules == [
Rule('start', [Alt([Maybe('_synthetic_rule_0')])]),
Rule('foo', [Alt(['NAME'])]),
Rule('_synthetic_rule_0',
[Alt(['foo', 'foo']), Alt(['foo'])])
]
def test_group():
program = ("start: (foo foo | foo)\n" "foo: NAME\n")
rules = start(program).rules
assert rules == [
Rule('start', [Alt(['_synthetic_rule_0'])]),
Rule('foo', [Alt(['NAME'])]),
Rule('_synthetic_rule_0',
[Alt(['foo', 'foo']), Alt(['foo'])])
]
def test_named_item():
program = ("start: f=foo\n" "foo: n=NAME\n")
file = StringIO(program)
tokengen = generate_tokens(file.readline)
tok = Tokenizer(tokengen)
p = GrammarParser(tok)
rules = p.start().rules
assert rules == [
Rule('start', [Alt([NamedItem('f', 'foo')])]),
Rule('foo', [Alt([NamedItem('n', 'NAME')])])
]
def test_action():
program = "start: NAME { foo + bar } | NUMBER { -baz }\n"
rules = start(program).rules
assert rules == [
Rule("start", [Alt(["NAME"], "foo + bar"),
Alt(["NUMBER"], "- baz")])
]
assert rules != [
Rule("start", [Alt(["NAME"], "foo + bar"),
Alt(["NUMBER"], "baz")])
]
def synthetic_rule(self, alts):
if len(alts) == 1 and len(alts[0].items) == 1:
return alts[0].items[0]
name = f"_synthetic_rule_{len(self.extra_rules)}"
rule = Rule(name, alts)
self.extra_rules.append(rule)
return rule.name
def test_indents2():
program = ("stmt:\n"
" | foo | bar\n"
" | baz\n"
" | booh | bah\n"
"foo: bar\n")
rules = start(program).rules
assert rules == [
Rule('stmt', [
Alt(['foo']),
Alt(['bar']),
Alt(['baz']),
Alt(['booh']),
Alt(['bah'])
]),
Rule('foo', [Alt(['bar'])])
]
def rule(self):
self.show_rule('rule', [[
'NAME', '":"', 'alts', 'NEWLINE', 'INDENT', 'more_alts', 'DEDENT'
], ['NAME', '":"', 'NEWLINE', 'INDENT', 'more_alts', 'DEDENT'],
['NAME', '":"', 'alts', 'NEWLINE']])
pos = self.mark()
if (True and self.show_index(0, 0)
and (name := self.expect(NAME)) is not None
and self.show_index(0, 1) and self.expect(":") is not None
and self.show_index(0, 2) and (alts := self.alts()) is not None
and self.show_index(0, 3)
and (newline := self.expect(NEWLINE)) is not None
and self.show_index(0, 4)
and (indent := self.expect(INDENT)) is not None
and self.show_index(0, 5)
and (more_alts := self.more_alts()) is not None
and self.show_index(0, 6)
and (dedent := self.expect(DEDENT)) is not None):
self.show_index(0, 0, 7)
retval = Rule(name.string, alts + more_alts)
if retval is not None:
return retval
retval = Rule(name.string, alts + more_alts)
if retval is not None:
return retval
self.reset(pos)
if (True and self.show_index(1, 0) and
(name := self.expect(NAME)) is not None and self.show_index(1, 1)
and self.expect(":") is not None and self.show_index(1, 2)
and (newline := self.expect(NEWLINE)) is not None
and self.show_index(1, 3)
and (indent := self.expect(INDENT)) is not None
and self.show_index(1, 4)
and (more_alts := self.more_alts()) is not None
and self.show_index(1, 5)
and (dedent := self.expect(DEDENT)) is not None):
self.show_index(1, 0, 6)
retval = Rule(name.string, more_alts)
if retval is not None:
return retval
self.reset(pos)
if (True and self.show_index(2, 0)
and (name := self.expect(NAME)) is not None
and self.show_index(2, 1) and self.expect(":") is not None
and self.show_index(2, 2) and (alts := self.alts()) is not None
and self.show_index(2, 3)
and (newline := self.expect(NEWLINE)) is not None):
self.show_index(2, 0, 4)
retval = Rule(name.string, alts)
if retval is not None:
return retval
self.reset(pos)
self.show_index(0, 0, 0)
def test_meta():
program = ("@start 'start'\n" "@foo bar\n" "@bar\n" "stmt: foo\n")
grammar = start(program)
assert grammar
assert grammar.rules == [Rule('stmt', [Alt(["foo"])])]
assert grammar.metas == [('start', 'start'), ('foo', 'bar'), ('bar', None)]
def test_cut():
program = "start: NAME ~ NAME\n"
rules = start(program).rules
assert rules == [Rule('start', [Alt(['NAME', Cut(), 'NAME'])])]
def test_lookahead_negative():
program = "start: !NUMBER NAME\n"
rules = start(program).rules
assert rules == [
Rule('start', [Alt([Lookahead('NUMBER', False), 'NAME'])])
]
def test_lookahead():
program = "start: &NUMBER NAME\n"
rules = start(program).rules
assert rules == [Rule('start', [Alt([Lookahead('NUMBER'), 'NAME'])])]
def test_plus():
program = "start: NAME+\n"
rules = start(program).rules
assert rules == [Rule('start', [Alt([Loop('NAME', True)])])]
def test_star():
program = "start: NAME*\n"
rules = start(program).rules
assert rules == [Rule('start', [Alt([Loop('NAME')])])]