functor
import
	System
	Application
define
	% Task 1
	proc {QuadraticEquation A B C ?RealSol ?X1 ?X2}
		local S = B*B + ~4.0*A*C in
			if S >= 0.0 then
				RealSol = true
				X1 = (~B + {Float.sqrt S})/(2.0 * A)
				X2 = (B + {Float.sqrt S})/(2.0 * A)
			else
				RealSol = false
			end
		end
	end

	local RealSol X1 X2 in
		{QuadraticEquation 2.0 1.0 ~1.0 RealSol X1 X2}
		if RealSol then
			{System.showInfo "Got real solution"}
			{System.showInfo "X1: "#X1}
			{System.showInfo "X2: "#X2}
		else
			{System.showInfo "No real solution"}
		end
	end
	local RealSol X1 X2 in
		{QuadraticEquation 2.0 1.0 2.0 RealSol X1 X2}
		if RealSol then
			{System.showInfo "Got real solution"}
			{System.showInfo "X1: "#X1}
			{System.showInfo "X2: "#X2}
		else
			{System.showInfo "No real solution"}
		end
	end

	% Task 2
	fun {Sum List}
		if List == nil then
			0
		else
			List.1 + {Sum List.2}
		end
	end

	{System.showInfo "Sum of list: "# {Sum [2 3 5 7]}}

	% Task 3
	fun {RightFold List Op U}
		if List == nil then
			U
		else
			{Op List.1 {RightFold List.2 Op U}}
		end
	end

	{System.showInfo "Mul of list: "# {RightFold [2 3 5] fun {$ X Y} X * Y end 1}}

	fun {NewSum List}
		{RightFold List fun {$ X Y} X + Y end 0}
	end
	fun {NewLength List}
		{RightFold List fun {$ X Y} 1 + Y end 0}
	end
	{System.showInfo "New Sum of list: "# {NewSum [2 3 5 7 11]}}
	{System.showInfo "New Length of list: "# {NewLength [2 3 5 7 11]}}

	% Task 4
	fun {Quadratic A B C}
		fun {$ X} A*X*X + B*X + C end
	end
	{System.showInfo {{Quadratic 3 2 1} 2}}

	% Task 5
	fun {LazyNumberGenerator X}
		X|fun {$} {LazyNumberGenerator X + 1} end
	end
	{System.showInfo {LazyNumberGenerator 0}.1}
	{System.showInfo {{LazyNumberGenerator 0}.2}.1}
	{System.showInfo {{{{{{LazyNumberGenerator 0}.2}.2}.2}.2}.2}.1}

	fun {TailRecursiveSumInternal List X}
		if List == nil then X else
			{TailRecursiveSumInternal List.2 X + List.1}
		end
	end
	fun {TailRecursiveSum List}
		{TailRecursiveSumInternal List 0}
	end

	fun {TailRecursiveLengthInternal List X}
		if List == nil then X else
			{TailRecursiveLengthInternal List.2 X + 1}
		end
	end
	fun {TailRecursiveLength List}
		{TailRecursiveLengthInternal List 0}
	end
	{System.showInfo "Tail Recursive Sum of list: "# {TailRecursiveSum [2 3 5 7 11]}}
	{System.showInfo "Tail Recursive Length of list: "# {TailRecursiveLength [2 3 5 7 11]}}
end