'<Eof>' Expected #16 Or "attempt To Call Nil" - ComputerCraft Forums (archive)

Ash__FTW #1

Ash__FTW's profile picture

3 posts

Posted 24 February 2012 - 01:11 PM


clearscreen()
print "Starting..."
redstone.setOutput("left" , true)
print "Loading Cannon..."
sleep(2)
print "Releasing Cannonball"
redstone.setOutput("right" , true)
print "Firing!"
redstone.setOutput("left" , false)
redstone.setOutput("right" , false)
sleep(3)
print "Reload Cannon."
end

That is my code at the moment to fire a cannon.
If i try to execute the program, i get this error.

[string "cannon"]:16: '<eof>' expected

I know this is because of the "end" So at first i removed it.
I then got the error:

"attempt to call nil"

I thought "Maybe i have to add an "end""
So i did.

[string "cannon"]:16: '<eof>' expected

The point is im fresh out of ideas… I need some help :huh:/>/>

Espen #2

715 posts

Posted 24 February 2012 - 01:26 PM

Is that your whole code? If so then clearscreen() is your problem.
You didn't define that function. If you want to clear the screen, then the correct command is:
term.clear()

For more info on term-commands, type: help term
Also for any future errors, take a look at this: http://www.computercraft.info/forums2/index.php?/topic/118-codex-of-error-slaying-2/

Edited on 24 February 2012 - 12:30 PM

Ash__FTW #3

Ash__FTW's profile picture

3 posts

Posted 24 February 2012 - 01:34 PM

Thanks i fixed it :huh:/>/>

But now what i want to add is an interface which triggers the mentioned code when the button "F" is pressed.

I made an Interface.


print "============================"
print "  Press [F] to fire cannon  "
print "============================"

I want this to stay on the computer until F is pressed.
F will trigger the code that i just fixed. How can i do this?

Espen #4

715 posts

Posted 24 February 2012 - 01:45 PM

Spoiler


while true do
	term.clear()
	print "============================"
	print "  Press [F] to fire cannon  "
	print "============================"
	local event, param = os.pullEvent()

	if event == "char" and param == "f" then
		term.clear()
		print "Starting..."
		redstone.setOutput("left" , true)
		print "Loading Cannon..."
		sleep(2)
		print "Releasing Cannonball"
		redstone.setOutput("right" , true)
		print "Firing!"
		redstone.setOutput("left" , false)
		redstone.setOutput("right" , false)
		sleep(3)
		print "Reload Cannon, then press ENTER."
		read()
	end
end

If you're on CC 1.3, then you can filter the watched events and thus shorten your code a tiny bit:

Spoiler


while true do
	term.clear()
	print "============================"
	print "  Press [F] to fire cannon  "
	print "============================"
	local event, param = os.pullEvent("char")

	if param == "f" then
		term.clear()
		print "Starting..."
		redstone.setOutput("left" , true)
		print "Loading Cannon..."
		sleep(2)
		print "Releasing Cannonball"
		redstone.setOutput("right" , true)
		print "Firing!"
		redstone.setOutput("left" , false)
		redstone.setOutput("right" , false)
		sleep(3)
		print "Reload Cannon, then press ENTER."
		read()
	end
end

Disclaimer: Haven't tested any of the code in-game, should work thought.
If you want to know more about events, type: help events

EDIT: Forgot an "if" in front of "param" in my second code example. Fixed.

Edited on 24 February 2012 - 01:10 PM

Ash__FTW #5

Ash__FTW's profile picture

3 posts

Posted 24 February 2012 - 01:52 PM

Worked perfectly other than it keeps scrolling down until the interface reaches the bottom of the screen.
How can i make it stay at the top?

Thanks for your help.

Espen #6

715 posts

Posted 24 February 2012 - 02:09 PM

That's because term.clear() only clears the screen, but it doesn't change the cursor position.
If you want the cursor to be set to position 1, 1 then you have to use term.setCursorPos(1, 1) like so:


while true do
		term.setCursorPos(1, 1)
		term.clear()
		print "============================"
		print "  Press [F] to fire cannon  "
		print "============================"
		local event, param = os.pullEvent("char")

		if param == "f" then
				term.clear()
				print "Starting..."
				redstone.setOutput("left" , true)
				print "Loading Cannon..."
				sleep(2)
				print "Releasing Cannonball"
				redstone.setOutput("right" , true)
				print "Firing!"
				redstone.setOutput("left" , false)
				redstone.setOutput("right" , false)
				sleep(3)
				print "Reload Cannon, then press ENTER."
				read()
		end
end

EDIT: ~~Hmm, something odd is going on that I can't see atm. Will report back when I found out why.~~
Nvm, the odd thing oddly vanished by itself. :huh:/>/>

Edited on 24 February 2012 - 01:20 PM