def visit_TheoryFunction(self, x):
"""
Theory functions are mapped to functions.
"""
isnum = lambda y: y.type == _ast.ASTType.Symbol and y.symbol.type == _clingo.SymbolType.Number
if x.name == "-" and len(x.arguments) == 1:
rhs = self(x.arguments[0])
if isnum(rhs):
return _ast.Symbol(x.location, _clingo.Number(-rhs.symbol.number))
else:
return _ast.UnaryOperation(x.location, _ast.UnaryOperator.Minus, rhs)
elif (x.name == "+" or x.name == "-") and len(x.arguments) == 2:
lhs = self(x.arguments[0])
rhs = self(x.arguments[1])
op = _ast.BinaryOperator.Plus if x.name == "+" else _ast.BinaryOperator.Minus
if isnum(lhs) and isnum(rhs):
lhs = lhs.symbol.number
rhs = rhs.symbol.number
return _ast.Symbol(x.location, _clingo.Number(lhs + rhs if x.name == "+" else lhs - rhs))
else:
return _ast.BinaryOperation(x.location, op, lhs, rhs)
elif x.name == "-" and len(x.arguments) == 2:
return _ast.BinaryOperation(x.location, _ast.BinaryOperator.Minus, self(x.arguments[0]), self(x.arguments[1]))
elif (x.name, TheoryParser.binary) in TheoryParser.table or (x.name, TheoryParser.unary) in TheoryParser.table:
raise RuntimeError("operator not handled: {}".format(str_location(x.location)))
else:
return _ast.Function(x.location, x.name, [self(a) for a in x.arguments], False)
def transform(self, atom):
loc = atom.location
false = self.__false_atom(loc)
atom, ranges = transform_theory_atom(atom)
variables = get_variables(atom)
param = time_parameter(loc)
shift = _ast.Variable(loc, g_tel_shift_variable)
aux = self.__aux_atom(loc, variables + [param])
saux = self.__aux_atom(loc, variables + [shift], inc=0)
rules = []
if self.__false_external is None:
rules.append(_tf.External(loc, false.atom, []))
rules.append(_ast.Rule(loc, atom, [aux]))
if ranges:
elems = []
for (lhs, rhs), heads in ranges:
cond = []
diff = _ast.BinaryOperation(loc, _ast.BinaryOperator.Minus, param, shift)
if lhs.ast_type != _ast.ASTType.SymbolicTerm or lhs.symbol.type != _clingo.SymbolType.Number or lhs.symbol.number > 0:
cond.append(_ast.Literal(loc, _ast.Sign.NoSign, _ast.Comparison(_ast.ComparisonOperator.LessEqual, lhs, diff)))
if rhs.ast_type != _ast.ASTType.SymbolicTerm or rhs.symbol.type != _clingo.SymbolType.Supremum:
cond.append(_ast.Literal(loc, _ast.Sign.NoSign, _ast.Comparison(_ast.ComparisonOperator.LessEqual, diff, rhs)))
elems.extend([_ast.ConditionalLiteral(loc, _ast.Literal(loc, _ast.Sign.NoSign, head), cond) for head in heads])
rules.append(_ast.Rule(loc, _ast.Disjunction(loc, elems), [saux, false]))
return aux, rules
def __get_param(self, name, location):
n = name.replace('\'', '')
primes = len(name) - len(n)
param = ast.SymbolicTerm(location, self.parameter)
if primes > 0:
param = ast.BinaryOperation(
location, ast.BinaryOperator.Minus, param,
ast.SymbolicTerm(location, Number(primes)))
return n, param
def transform(inputs, callback):
"""
Transforms the given list of temporal programs in string form into an ASP
program.
Returns the future predicates whose atoms have to be set to false if
referring to the future, and program parts that have to be regrounded if
there are constraints referring to the future.
Arguments:
inputs -- The list of inputs.
callback -- Callback for rewritten statements.
"""
loc = {
'begin': {
'line': 1,
'column': 1,
'filename': '<transform>'
},
'end': {
'line': 1,
'column': 1,
'filename': '<transform>'
}
}
future_predicates = set()
constraint_parts = {}
time = _ast.Symbol(loc, _clingo.Function(_tf.g_time_parameter_name))
wrap_lit = lambda a: _ast.Literal(loc, _ast.Sign.NoSign, a)
# apply transformer to program
def append(s):
if s is not None:
callback(s)
aux_rules = []
transformer = _prg.ProgramTransformer(future_predicates, constraint_parts,
aux_rules)
for i in inputs:
_clingo.parse_program(i, lambda s: append(transformer.visit(s)))
if aux_rules:
callback(
_ast.Program(loc, "always", [
_ast.Id(loc, _tf.g_time_parameter_name),
_ast.Id(loc, _tf.g_time_parameter_name_alt)
]))
for rule in aux_rules:
callback(rule)
# add auxiliary rules for future predicates
future_sigs = []
if len(future_predicates) > 0:
callback(
_ast.Program(loc, "always", [
_ast.Id(loc, _tf.g_time_parameter_name),
_ast.Id(loc, _tf.g_time_parameter_name_alt)
]))
for name, arity, positive, shift in sorted(future_predicates):
variables = [
_ast.Variable(loc, "{}{}".format(_tf.g_variable_prefix, i))
for i in range(arity)
]
s = _ast.Symbol(loc, _clingo.Number(shift))
t_shifted = _ast.BinaryOperation(loc, _ast.BinaryOperator.Plus,
time, s)
add_sign = lambda lit: lit if positive else _ast.UnaryOperation(
loc, _ast.UnaryOperator.Minus, lit)
p_current = _ast.SymbolicAtom(
add_sign(_ast.Function(loc, name, variables + [time], False)))
f_current = _ast.SymbolicAtom(
add_sign(
_ast.Function(loc, _tf.g_future_prefix + name,
variables + [s, time], False)))
callback(_ast.Rule(loc, wrap_lit(p_current),
[wrap_lit(f_current)]))
future_sigs.append(
(_tf.g_future_prefix + name, arity + 2, positive))
# gather rules for constraints referring to the future
reground_parts = []
if len(constraint_parts) > 0:
for (name, shift), rules in constraint_parts.items():
assert (shift > 0)
params = [
_ast.Id(loc, _tf.g_time_parameter_name),
_ast.Id(loc, _tf.g_time_parameter_name_alt)
]
# parts to be regrounded
part = "{}_0_{}".format(name, shift - 1)
callback(_ast.Program(loc, part, params))
for p, l in rules:
callback(p)
reground_parts.append((name, part, range(shift)))
# parts that no longer have to be regrounded
last_part = "{}_{}".format(name, shift)
callback(_ast.Program(loc, last_part, params))
for p, l in rules:
callback(l)
reground_parts.append((name, last_part, range(shift, shift + 1)))
def add_part(part_name, atom_name, statement, wrap=lambda x: x):
params = [
_ast.Id(loc, _tf.g_time_parameter_name),
_ast.Id(loc, _tf.g_time_parameter_name_alt)
]
callback(_ast.Program(loc, part_name, params))
atom = wrap(
_ast.SymbolicAtom(_ast.Function(loc, atom_name, [time], False)))
callback(statement(loc, atom, []))
add_part('initial', '__initial', _ast.Rule, wrap_lit)
add_part('always', '__final', _tf.External)
reground_parts.append(('always', 'always', range(1)))
reground_parts.append(('dynamic', 'dynamic', range(1)))
reground_parts.append(('initial', 'initial', range(1)))
def no_program(s):
if s.type != _ast.ASTType.Program:
callback(s)
_clingo.parse_program(
_dedent('''\
#theory tel {
formula_body {
& : 7, unary; % prefix for keywords
- : 7, unary; % classical negation
+ : 6, binary, left; % arithmetic +
- : 6, binary, left; % arithmetic -
~ : 5, unary; % negation
< : 5, unary; % previous
< : 5, binary, right; % n x previous
<: : 5, unary; % weak previous
<: : 5, binary, right; % n x weak previous
<? : 5, unary; % eventually-
<* : 5, unary; % always-
<< : 5, unary; % initially
> : 5, unary; % next
> : 5, binary, right; % n x next
>: : 5, unary; % weak next
>: : 5, binary, right; % n x weak next
>? : 5, unary; % eventually+
>* : 5, unary; % always+
>> : 5, unary; % finally
>* : 4, binary, left; % release
>? : 4, binary, left; % until
<* : 4, binary, left; % trigger
<? : 4, binary, left; % since
& : 3, binary, left; % and
| : 2, binary, left; % or
<- : 1, binary, left; % left implication
-> : 1, binary, left; % right implication
<> : 1, binary, left; % equivalence
;> : 0, binary, right; % sequence next
;>: : 0, binary, right; % sequence weak next
<; : 0, binary, left; % sequence previous
<:; : 0, binary, left % sequence weak previous
};
formula_head {
& : 7, unary; % prefix for keywords
- : 7, unary; % classical negation
+ : 6, binary, left; % arithmetic +
- : 6, binary, left; % arithmetic -
~ : 5, unary; % negation
> : 5, unary; % next
> : 5, binary, right; % n x next
>: : 5, unary; % weak next
>: : 5, binary, right; % n x weak next
>? : 5, unary; % eventually+
>* : 5, unary; % always+
>> : 5, unary; % finally
>* : 4, binary, left; % release
>? : 4, binary, left; % until
& : 3, binary, left; % and
| : 2, binary, left; % or
;> : 0, binary, right; % sequence next
;>: : 0, binary, right % sequence weak next
};
&tel/1 : formula_body, body;
&__tel_head/1 : formula_body, head
}.
'''), no_program)
_clingo.parse_program(
_dedent('''\
#theory del {
formula_body {
& : 7, unary; % prefix for keywords
? : 4, unary; % check
* : 3, unary; % kleene star
+ : 2, binary, left; % choice
;; : 1, binary, left; % sequence
.>? : 0, binary, right; % diamond (eventually)
.>* : 0, binary, right % box (always)
};
&del/1 : formula_body, body
}.
'''), no_program)
return future_sigs, reground_parts
def __get_param(self, name, arity, location, replace_future, fail_future,
fail_past, max_shift):
"""
Strips previous and next operators from function names
and returns the updated name plus the time arguments to append.
Furthermore, if the initially operator (_ prefix) is used, then the
time parameter is replaced with 0. Otherwise, it is treated like a past
operator.
If replace_future is set this also introduces a new name for the
predicate, which is recorded in the list of atoms that have to be made
redefinable. In this case the name is prefixed with __future_. Such
dynamic predicates are recorded in the future_predicates list.
Arguments:
name -- The name of the predicate
(trailing primes denote previous operators).
location -- Location for generated terms.
replace_future -- Whether atoms referring to the future have to be
replaced by a special future atom.
fail_future -- Fail if the atom refers to the future.
fail_past -- Fail if the atom refers to the past.
max_shift -- The maximum number of steps terms look into the
future.
Example for body atoms:
p(X) :- 'q(X)
becomes
p(X,t) :- q(X,t-1)
Example for head atoms (replace_future=True):
p''(X) :- q(X).
becomes
__future__p(X,2,t) :- q(X,t).
and future_predicates is extended with (p,1,2) -> False
"""
n = name.strip("'")
shift = 0
for c in name:
if c == "'":
shift -= 1
else:
break
shift += len(name) - len(n) + shift
initially = False
if n.startswith("_") and not n.startswith("__"):
n = n[1:]
if n.startswith("'") or name.startswith("'") or name.endswith("'"):
raise RuntimeError(
"initially operator cannot be used with primes: {}".format(
_tf.str_location(location)))
initially = True
finally_ = False
if n.endswith("_") and not n.endswith("__"):
n = n[:-1]
if n.endswith("'") or name.startswith("'") or name.endswith("'"):
raise RuntimeError(
"finally operator cannot be used with primes: {}".format(
_tf.str_location(location)))
finally_ = True
raise RuntimeError("finally operator not yet supported: {}".format(
_tf.str_location(location)))
if initially and finally_:
raise RuntimeError(
"finally and initially operator cannot used together: {}".
format(_tf.str_location(location)))
params = [
_ast.Symbol(location, _clingo.Function(_tf.g_time_parameter_name))
]
if fail_future and (shift > 0 or finally_):
raise RuntimeError(
"future atoms not supported in this context: {}".format(
_tf.str_location(location)))
if fail_past and (shift < 0 or initially):
raise RuntimeError(
"past atoms not supported in this context: {}".format(
_tf.str_location(location)))
if shift > 0:
if replace_future:
self.__future_predicates.add(
(n, arity, self.__positive, shift))
n = _tf.g_future_prefix + n
params.insert(0, _ast.Symbol(location, shift))
else:
max_shift[0] = max(max_shift[0], shift)
if shift != 0:
params[-1] = _ast.BinaryOperation(location,
_ast.BinaryOperator.Plus,
params[-1],
_ast.Symbol(location, shift))
elif initially:
params[-1] = _ast.Symbol(location, 0)
return (n, params)
def visit_BinaryOperation(self, x):
"""
BinaryOperation(location: Location, operator: BinaryOperator, left: term, right: term)
"""
return [ast.BinaryOperation(x.location, x.operator, l, r) for l, r in product(self.visit(x.left), self.visit(x.right))]
