// Package codec defines processes to convert between different representations
// of lambda calculus, and serialize the different representations.
package codec

// A Conversion is a function that turns one representation into another.
// Returns an error if the input expression cannot be converted.
type Conversion[T, U any] = func(T) (U, error)

// A Codec is an object that can serialize/deserialize one type of
// representation. It is assumed that for any x ∋ T, Decode(Encode(x)) = x.
type Codec[T any] interface {
	// Encode takes an expression, and returns its serialized format, as a
	// string. Returns an error if the expression cannot be serialized.
	Encode(T) (string, error)

	// Decode takes the serialized format of an expression, and returns its true
	// value. Returns an error if the string doesn't correctly represent any
	// valid expression.
	Decode(string) (T, error)
}