def test_non_halting_left_recursive():
h1 = fwd()
h1.define(x + h1)
ok_(not non_halting(h1))
h2 = fwd()
h2.define(x + (h2 | x))
ok_(not non_halting(h2))
nh1 = fwd()
nh1.define(nh1 + x)
ok_(non_halting(nh1))
nh2 = fwd()
nh2.define(x | nh2)
ok_(non_halting(nh2))
nh3_fwd = fwd()
nh3_fwd.define(nh3_fwd)
nh3 = x + nh3_fwd + x
ok_(non_halting(nh3))
nh4 = fwd()
nh4.define(maybe(x) + nh4 + x)
ok_(non_halting(nh4))
nh5 = fwd()
nh5.define(many(x) + maybe(x) + nh5 + x)
ok_(non_halting(nh5))
h3 = fwd()
h3.define(maybe(x) + many(x) + x + h3)
ok_(not non_halting(h3))
def test_non_halting_left_recursive():
h1 = fwd()
h1.define(x + h1)
ok_(not non_halting(h1))
h2 = fwd()
h2.define(x + (h2 | x))
ok_(not non_halting(h2))
nh1 = fwd()
nh1.define(nh1 + x)
ok_(non_halting(nh1))
nh2 = fwd()
nh2.define(x | nh2)
ok_(non_halting(nh2))
nh3_fwd = fwd()
nh3_fwd.define(nh3_fwd)
nh3 = x + nh3_fwd + x
ok_(non_halting(nh3))
nh4 = fwd()
nh4.define(maybe(x) + nh4 + x)
ok_(non_halting(nh4))
nh5 = fwd()
nh5.define(many(x) + maybe(x) + nh5 + x)
ok_(non_halting(nh5))
h3 = fwd()
h3.define(maybe(x) + many(x) + x + h3)
ok_(not non_halting(h3))
return unichr(int(m.group('unicode'), 16))
return re_esc.sub(sub, s)
def make_string(n):
return unescape(n[1:-1])
# JSON Grammar
null = n('null') >> const(None)
true = n('true') >> const(True)
false = n('false') >> const(False)
number = sometok('number') >> make_number
string = sometok('string') >> make_string
value = fwd()
member = string + op_(':') + value >> tuple
object = (op_('{') + maybe(member + many(op_(',') + member)) + op_('}') >>
make_object)
array = (
op_('[') + maybe(value + many(op_(',') + value)) + op_(']') >> make_array)
value.define(null | true | false | object | array | number | string)
json_text = object | array
json_file = json_text + skip(eof)
name_parser_vars(locals())
def parse(seq):
'Sequence(Token) -> object'
return json_file.parse(seq)
string = sometok('string') >> make_string
func = sometok('func') >> make_func
value = number | name | string
makeop = lambda s, f: op(s) >> const(f)
add = makeop('+', (ets.add, operator.add))
sub = makeop('-', (ets.sub, operator.sub))
mul = makeop('*', (ets.mul, operator.mul))
div = makeop('/', (ets.div, operator.div))
mul_op = mul | div
add_op = add | sub
args = fwd()
factor = fwd()
primary = value
call = func + op_('(') + args + op_(')') >> exec_func
term = factor + many(mul_op + factor ) >> eval
expr = term + many(add_op + term ) >> eval
top = expr + skip(eof)
args.define(
expr + many( op_(',') + expr )
)
factor.define(
call | primary | op_('(') + expr + op_(')')
)
name_parser_vars(locals())
def make_object(n):
return PLObject(n)
def make_name(n):
assert len(n) == 2
return PLName(n[0], n[1])
def make_array(n):
return PLArray(n)
number = sometok('number') >> make_number
string = sometok('string') >> make_string
comment = sometok('comment') >> make_comment
name = (sometok('name') | sometok('string')) + maybe(comment) >> make_name
value = fwd()
member = name + op_('=') + value >> make_member
section = maybe(comment) + oneplus(member + op_(';')) + maybe(comment) >> make_section
object = (
op_('{') +
many(section) +
op_('}')) >> make_object
array = (
op_('(') +
many(value + op_(',')) +
op_(')')) >> make_array
value.define(
object
| number
| name
| array)
id +
maybe(op_('=') + id) +
skip(maybe(op(',')))
>> unarg(Attr))
attr_list = (
many(op_('[') + many(a_list) + op_(']'))
>> flatten)
attr_stmt = (
(n('graph') | n('node') | n('edge')) +
attr_list
>> unarg(DefAttrs))
graph_attr = id + op_('=') + id >> make_graph_attr
node_stmt = node_id + attr_list >> unarg(Node)
# We use a fwd() because of circular definitions like (stmt_list -> stmt ->
# subgraph -> stmt_list)
subgraph = fwd()
edge_rhs = skip(op('->') | op('--')) + (subgraph | node_id)
edge_stmt = (
(subgraph | node_id) +
oneplus(edge_rhs) +
attr_list
>> unarg(make_edge))
stmt = (
attr_stmt
| edge_stmt
| subgraph
| graph_attr
| node_stmt
)
stmt_list = many(stmt + skip(maybe(op(';'))))
subgraph.define(memoize(
'str -> Sequence(Token)'
specs = [
('space', (r'[ \t\r\n]+',)),
('int', (r'-?[1-9][0-9]*|0',)),
('true', (r'#t',)),
('false', (r'#f',)),
('char', (r'#\\[A-Za-z_0-9]',)),
('op', (r'[\[\]\(\)\']', re.VERBOSE)),
('name', (r'[A-Za-z_0-9\&\*\+\-\~!\=<>\^/,\?:;.]*',)),
]
useless = ['space']
t = make_tokenizer(specs)
return [x for x in t(str) if x.type not in useless]
sexpr = fwd()
integer = sometok('int') >> int
symbol = sometok('name') >> Symbol
true = sometok('true') >> const(True)
false = sometok('false') >> const(False)
boolean = true | false
char = sometok('char') >> (lambda x: x[2])
dotlist = op_('(') + many(sexpr) + op_(')') >> (lambda x: x or None)
quote = op_('\'') + sexpr >> (lambda x: [Symbol('quote'), sexpr])
sexpr.define(
integer
| symbol
| boolean
| char
| dotlist
)
else:
s = n.decode("string-escape")
return runtime.find("String" if prefix == "u" else "Bytes").clone(s)
def make_terminator(n):
return Message(n.value)
operator = sometok("operator")
identifier = sometok("identifier")
string = sometok("string") >> make_string
number = sometok("number") >> make_number
expression = fwd()
arguments = fwd()
message = fwd()
symbol = fwd()
terminator = (op(";") | op("\r") | op("\n")) >> make_terminator
expression.define((
many(message | terminator)) >> make_expression)
message.define(((symbol + maybe(arguments)) | arguments) >> make_message)
paren_arguments = op(
"(") + maybe(expression) + many(skip(op_(",")) + expression) + op(")")
bracket_arguments = op(
"[") + maybe(expression) + many(skip(op_(",")) + expression) + op("]")