Errors when following tutorial

Monkey Forums/Monkey Beginners/Errors when following tutorial

Vectrix Quest

(Posted 2014) [#1]

I was watching and following the video tutorials referenced here: [url]http://www.monkey-x.com/Community/posts.php?topic=3318&page=1[/url] and have run into a snag. When i try to run my code i get the error:

Main.monkey<26> : Error : Syntax error - expecting identifier.

My code is very identical to the one presented in the tutorial with a few minor differences. Here is the code I'm using:

' import required libraries
Import mojo

' constants
Const STATE_MENU:Int = 0
Const STATE_GAME:Int = 1
Const STATE_GAMEOVER:Int = 2

Class VectrixQuest Extends App

	' holds games current state
	Field gameState:Int = STATE_MENU

	Method onCreate()
		'set update rate
		SetUpdateRate(30)
	End

	Method onUpdate()
		' perform actions based on game state
		Select gameState

			' menu screen state
			Case STATE_MENU
				' draw the title text
				DrawText("Vectrix Quest", 320. 240, 0.5)
			' game state
			Case STATE_GAME

			' game over state
			Case STATE_DEATH

		End
	End

	Method onRender()
		' clear the screen
		cls(0,0,0)

		' perform actions based on game state
		Select gameState

			' menu screen state
			Case STATE_MENU

			' game state
			Case STATE_GAME

			' game over state
			Case STATE_DEATH

		End
	End
End

Function Main()
	New VectrixQuest()
End

Any assistance in this matter would be greatly appreciated.

Sincerely,

Vectrix Quest

Danilo

(Posted 2014) [#2]

You made a small typo: point/dot instead comma.

Change

DrawText("Vectrix Quest", 320. 240, 0.5)

DrawText("Vectrix Quest", 320, 240, 0.5)

Powelly

(Posted 2014) [#3]

Also, Monkey is a case sensitive language, so your method names should be OnCreate, OnUpdate, OnRender, etc.

You should do your drawing in the OnRender method, so you should move your DrawText line of code from OnUpdate into OnRender.

Hope that helps.

Danilo

(Posted 2014) [#4]

Interesting. Monkey does not catch the other errors if it does not include the methods.
After changing the method names to OnCreate, OnUpdate, and OnRender, more
errors come up: cls() -> Cls(), STATE_DEATH -> STATE_GAMEOVER

Changed code:

' import required libraries
Import mojo

' constants
Const STATE_MENU:Int = 0
Const STATE_GAME:Int = 1
Const STATE_GAMEOVER:Int = 2

Class VectrixQuest Extends App

	' holds games current state
	Field gameState:Int = STATE_MENU

	Method OnCreate()
		'set update rate
		SetUpdateRate(30)
	End

	Method OnUpdate()
		' perform actions based on game state
		Select gameState

			' menu screen state
			Case STATE_MENU
			
			' game state
			Case STATE_GAME

			' game over state
			Case STATE_GAMEOVER

		End
	End

	Method OnRender()
		' clear the screen
		Cls(0,0,0)

		' perform actions based on game state
		Select gameState

			' menu screen state
			Case STATE_MENU
				' draw the title text
				DrawText("Vectrix Quest", 320, 240, 0.5)

			' game state
			Case STATE_GAME

			' game over state
			Case STATE_GAMEOVER

		End
	End
End

Function Main()
	New VectrixQuest()
End

Jesse

(Posted 2014) [#5]

it's because the methods never get called. And if they don't get called, they get removed from the program. It is as if the method and code don't exist. It's due to Monkey's aggressive dead code elimination.

MikeHart

(Posted 2014) [#6]

Make it a habit to start your code with the strict keyword. Also using reflection helps finding bad code in unused code sections.

Danilo

(Posted 2014) [#7]

I expected the optimization (dead code elimination) to come after the syntax check.

No problem, just good to know. ;)

Strict

Import mojo

Class Game Extends App

    Method NeverCalled:Void()
        this gets never called
        so no syntax check
    End

    Method OnCreate:Int()
        SetUpdateRate(30)
        Return 0
    End

    Method OnRender:Int()
        Cls(64,64,64)
        Return 0
    End
End

Function Main:Int()
    New Game()
    Return 0
End