#[derive(Eq, Hash, PartialEq)]
pub struct PredicateDeclaration
{
	pub name: String,
	pub arity: usize,
}

#[derive(PartialEq)]
pub struct Predicate
{
	pub declaration: PredicateDeclaration,
	pub arguments: Vec<Term>,
}

#[derive(PartialEq)]
pub struct Exists
{
	pub parameters: Vec<VariableDeclaration>,
	pub argument: Box<Formula>,
}

#[derive(PartialEq)]
pub struct ForAll
{
	pub parameters: Vec<VariableDeclaration>,
	pub argument: Box<Formula>,
}

#[derive(PartialEq)]
pub enum ImplicationDirection
{
	LeftToRight,
	RightToLeft,
}

#[derive(PartialEq)]
pub enum Formula
{
	Exists(Exists),
	ForAll(ForAll),
	Not(Box<Formula>),
	And(Vec<Box<Formula>>),
	Or(Vec<Box<Formula>>),
	Implies(Box<Formula>, Box<Formula>, ImplicationDirection),
	Biconditional(Box<Formula>, Box<Formula>),
	Less(Term, Term),
	LessOrEqual(Term, Term),
	Greater(Term, Term),
	GreaterOrEqual(Term, Term),
	Equal(Term, Term),
	NotEqual(Term, Term),
	Boolean(bool),
	Predicate(Predicate),
}

#[derive(Eq, Hash, PartialEq)]
pub enum Domain
{
	Program,
	Integer,
}

#[derive(PartialEq)]
pub struct VariableDeclaration
{
	pub name: String,
	pub domain: Domain,
}

#[derive(PartialEq)]
pub enum Term
{
	Infimum,
	Supremum,
	Integer(i64),
	Symbolic(String),
	String(String),
	Variable(VariableDeclaration),
	Add(Box<Term>, Box<Term>),
	Subtract(Box<Term>, Box<Term>),
	Multiply(Box<Term>, Box<Term>),
	Negative(Box<Term>),
}