package saccharine

import (
	"git.maximhutz.com/max/lambda/pkg/repr"
)

type Expression interface {
	repr.Repr
}

var (
	_ Expression = Abstraction{}
	_ Expression = Application{}
	_ Expression = Variable{}
	_ Expression = Clause{}
)

/** ------------------------------------------------------------------------- */

type Abstraction struct {
	Parameters []string
	Body       Expression
}

func NewAbstraction(parameter []string, body Expression) *Abstraction {
	return &Abstraction{Parameters: parameter, Body: body}
}

/** ------------------------------------------------------------------------- */

type Application struct {
	Abstraction Expression
	Arguments   []Expression
}

func NewApplication(abstraction Expression, arguments []Expression) *Application {
	return &Application{Abstraction: abstraction, Arguments: arguments}
}

/** ------------------------------------------------------------------------- */

type Variable struct {
	Name string
}

func NewVariable(name string) *Variable {
	return &Variable{Name: name}
}

/** ------------------------------------------------------------------------- */

type Clause struct {
	Statements []Statement
	Returns    Expression
}

func NewClause(statements []Statement, returns Expression) *Clause {
	return &Clause{Statements: statements, Returns: returns}
}