37 enum type { False, True, EmptyWord };
38 virtual void accept(
visitor& v)
const override;
47 const char* val_name()
const;
49 virtual std::string
dump()
const override;
67 static constant empty_word_instance_;
79 is_constant(
const formula* f)
81 if (f->kind() != formula::Constant)
83 return static_cast<const constant*
>(f);
A constant (True or False)
Definition: constant.hh:34
Formula visitor.
Definition: visitor.hh:40
type val() const
Return the value of the constant.
Definition: constant.hh:41
static constant * empty_word_instance()
Get the sole instance of spot::ltl::constant::constant(EmptyWord).
Definition: constant.hh:56
SPOT_API std::ostream & dump(std::ostream &os, const formula *f)
Dump a formula tree.
static constant * true_instance()
Get the sole instance of spot::ltl::constant::constant(True).
Definition: constant.hh:52
static constant * false_instance()
Get the sole instance of spot::ltl::constant::constant(False).
Definition: constant.hh:54