# Experimental Math Rocks
# Math-640 Project: Explore Solitaire games using Depth First Search (DFS)
# Phil Benjamin

# Control flow program and test program

HelpDFS := proc()
	print(`DFScontrol()`);
end proc:

# General DFS Control

# All arguments to this proc are procs applied to the problem
# All procs use global variables (thus using information hiding from control)

DFScontrol := proc(Init,IsTerm,NextProg,NextAlt,NextBack)
	local stepSuccess,backSuccess,termSuccess;
	Init();
	if IsTerm() then return true; end if;
	stepSuccess := true; termSuccess := false;
	while stepSuccess and not termSuccess do
		stepSuccess := NextProg();
		if not stepSuccess then
			stepSuccess := NextAlt();
		end if;
		if not stepSuccess then
			# Need to backtrack until success
			backSuccess := true;
			while backSuccess and not stepSuccess do
				backSuccess := NextBack();
				if backSuccess then
					stepSuccess := NextAlt();
				end if;
			end do;
		end if;
		if stepSuccess then
			termSuccess := IsTerm();
		end if;
	end do;
	return termSuccess;	
end proc:

# Test procs
with(Maplets[Examples]):
TestGetInput := proc(myMsg,myTitle)
	return parse(GetInput(myMsg,title=myTitle));
end proc:
TestMsg := proc(myMsg)
	return Message(myMsg,title="Note",type=information);
end proc:

# Test DFScontrol
TestGlobalState := "":
TestDFScontrol := proc()
	return DFScontrol(TestInit,TestIsTerm,
	TestNextProg,TestNextAlt,TestNextBack);
end proc:

TestInit := proc()
	global TestGlobalState;
	TestGlobalState := GetInput("Init:");
end proc:
TestIsTerm := proc()
	global TestGlobalState;
	return parse(GetInput(cat("IsTerm: ",TestGlobalState)));
end proc:
TestNextProg := proc()
	global TestGlobalState;
	local NewGlobalState;
	NewGlobalState := GetInput("NextProg:",value=TestGlobalState);
	if NewGlobalState <> TestGlobalState then
		TestGlobalState := NewGlobalState;
		return true;
	end if;
	return false;
end proc:

TestNextAlt := proc()
	global TestGlobalState;
	local NewGlobalState;
	NewGlobalState := GetInput("NextAlt:",value=TestGlobalState);
	if NewGlobalState <> TestGlobalState then
		TestGlobalState := NewGlobalState;
		return true;
	end if;
	return false;
end proc:

TestNextBack := proc()
	global TestGlobalState;
	local NewGlobalState;
	NewGlobalState := GetInput("NextBack:",value=TestGlobalState);
	if NewGlobalState <> TestGlobalState then
		TestGlobalState := NewGlobalState;
		return true;
	end if;
	return false;
end proc: