Interface Term

ast/ast.go:121–134

Term represents the building blocks of datalog programs, namely constants, variables, atoms, and also negated atoms, equality and inequality. Some minor differences to formal mathematical logic and prolog-style logic programming: - an Atom in datalog is always a predicate symbol applied to constant

// convention gives us a 1:1 mapping between term objects and their string representations, and
// this is useful because Atom is not a hashable type (use String() to use Term as key in maps).
type Term interface {
	// Marker method.
	isTerm()

	// Returns a string representation.
	String() string

	// Syntactic (or structural) equality.
	// If Equals returns true, terms have the same string representation.
	Equals(Term) bool

	// Returns a new term.
	ApplySubst(s Subst) Term
}

// BaseTerm represents a subset of terms: constant, variables or ApplyFn.
// Every BaseTerm will implement Term.