package parser

import "sfdl/scanner"

type ExprNode struct {
	Op    scanner.TokenType
	Left  *ExprNode
	Right *ExprNode
	Value float64
	Func  func(float64) float64
}

func NewConstNode(v float64) *ExprNode {
	return &ExprNode{
		Op:    scanner.CONST_ID,
		Value: v,
	}
}

func NewTNode() *ExprNode {
	return &ExprNode{
		Op: scanner.T,
	}
}

func NewFuncNode(fn func(float64) float64, child *ExprNode) *ExprNode {
	return &ExprNode{
		Op:   scanner.FUNC,
		Left: child,
		Func: fn,
	}
}

func NewBinaryNode(op scanner.TokenType, left, right *ExprNode) *ExprNode {
	return &ExprNode{
		Op:    op,
		Left:  left,
		Right: right,
	}
}

func NewUnaryNode(op scanner.TokenType, child *ExprNode) *ExprNode {
	if op == scanner.PLUS {
		return child
	}
	// -x -> 0 - x
	if op == scanner.MINUS {
		zero := NewConstNode(0)
		return NewBinaryNode(scanner.MINUS, zero, child)
	}
	return child
}