Basic JASS Help (takes/returns, how to convert GUI?)

[Mr_Bean]

Hello guys,

I have been using GUI for a while now and I am pretty good with it. I have decided to learn JASS now. I have been reading a tutorial which is good, but there are a few things I don't understand. I have a few questions:

1. Please explain what is meant by takes.
2. Please explain what is meant by returns.
3. How would I convert this basic trigger into a JASS script (I have tried converting it to a custom text but that's confusing)?

• Trigger
  • Events
    • Unit - A unit enters Region1
  • Conditions
    • (Unit-type of (Triggering unit)) Equal to Wisp
  • Actions
    • Set Temp_Point = (Position of (Triggering Unit))
    • Special Effect - Create a special effect at Temp_Point using Abilities\Spells\Human\ThunderClap\ThunderClapCaster.mdl
    • Special Effect - Destroy (Last created special effect)
    • Unit - Kill (Triggering unit)
    • Custom script: call RemoveLocation(udg_Temp_Point)

That's it for now. Thanks,

- Mr_Bean

 

[Pharaoh_]

Takes is a keyword for the parameters. A function can take certain parameters to begin its functionality.

function ExAuror takes unit u returns nothing
endfunction

This function, in order to work, must get a parameter of a unit id. How would you call it:

call ExAuror (GetTriggerUnit())

A function can simultaneously take several parameters, all of them getting separated by a comma:

function f takes unit u, inter i, real r returns nothing
endfunction

By the time the function "takes" the unit, the syntax allows to a pseudo-store (check: takes unit u), a name to use it as a reference to the parameter you take. That pseudo-variable doesn't need to be nulled, as you would do in other case.

The "returns" keyword is what a function would return. Let's say you want a function to give you a value, when you relate it to a unit. I will not create a custom function for this, I will instead show you the default function of GetWidgetLife().
This function allows you to check the life of any object, item, unit, destructable.
It goes like: function GetWidgetLife takes unit u returns real. When you add the parameter of "u", it checks the life of the unit and returns that value in real. This is also how the GUI works:

• Set RealVariable = (Life of (Triggering unit))

You need to learn Jass basics, because if I proceed with coordinates, when you are used to "locations", it can be quite complicated.
Use the following references:
• https://www.hiveworkshop.com/forums/jass-ai-scripts-tutorials-280/basic-jass-tips-22947/
• https://www.hiveworkshop.com/forums...als-280/beginning-jass-tutorial-series-30765/
• https://www.hiveworkshop.com/forums/jass-ai-scripts-tutorials-280/jass-moving-gui-jass-start-40617/ <- This one is really important for you.

 

[Mr_Bean]

Okay, thanks for your help. Just a stupid question, I have a script like this:

function Leave_Area takes nothing returns nothing
    local location Temp_Point = GetUnitLoc(GetTriggerUnit())
    if GetTriggerPlayer() == Player(0) then
        call DisplayTextToPlayer(GetTriggerPlayer(), 0, 0, "Don't leave!")
        call AddSpecialEffectLoc("AOws", Temp_Point)
        call DestroyEffect(GetLastCreatedEffectBJ())
    endif
endfunction

How would I call this function using triggers? I have something like this, but it gives errors:

• Leave Area
  • Events
    • Unit - A unit enters Effect <gen>
  • Conditions
  • Actions
    • Custom script: call Leave_Area()

I guess my question is: how to use the "()" in the custom script. Thanks,

- Mr_Bean

 

[Tirlititi]

You are doing it fine. I think you get an error because you call the function before you declare it (ie. : your GUI trigger is placed before the jass function).
If you want to be sure that the worldedit compiles it in the right order, you can both :
- Put your function in the "custom script part", which is available by clicking on the map icon at the top of your triggers.
- Or use the JNGP and put your function into a library :

library LeaveArea_Lib

    function Leave_Area takes nothing returns nothing
        ........
    endfunction

endlibrary

Libraries are always placed before the "custom script part" that is itself placed before regular triggers.

 

[Mr_Bean]

I don't think that's the problem. I can't save the map after inserting the custom script. Shouldn't I put parameters into the "()"? If so, what should they be in this case? Here is the error message:

Thanks,

- Mr_Bean

 

[Pharaoh_]

You need to move the function Leave_Area to the map's header, that's what Tirlititi proposed; but, if you turn it into a library (vJass, you will need JNGP program), it can be included within a trigger.

 

[Tirlititi]

That IS the problem. Your trigger is somehow at the top of the map's script...
To be clear, this will cause an error :

function A takes nothing returns nothing
    call B()
endfunction

function B takes nothing returns nothing
endfunction

You must put them in the right order :

function B takes nothing returns nothing
endfunction

function A takes nothing returns nothing
    call B()
endfunction

I don't know what you make to put the function "Trig_Leave_Area_Actions" at top, but it definitely must be put after the function "Leave_Area".

EDIT : too slow ^^.

 

[Mr_Bean]

That IS the problem. Your trigger is somehow at the top of the map's script...

Sorry, I'm really noob at JASS. I only want to call the function "Leave Area" when a unit enters the region "Effect". How would I do this?

Thanks,

- Mr_Bean

 

[Geries]

1. Make sure that the trigger you call the function is downer than that what contains the function

This is not good:
Gui trigger
Jass trigger

Good:
Jass trigger
Gui trigger

2. If still gives error close editor and reopen. It should work.

3. If still gives error then you may not have a jass compatible world editor-> download JNGP

4. If you have JNGP and it isconfigured well then upload your map and we will check

 

[Mr_Bean]

Okay, thanks guys, I seem to have sorted it out. One more quick question: What is wrong with this:

function Leave_Area takes nothing returns nothing
    local location Temp_Point = GetUnitLoc(GetTriggerUnit())
    if (GetLocalPlayer() == Player (0)) then
        call DisplayTextToPlayer(Player(0), 0, 0, "Hi")
        call AddSpecialEffectTargetUnitBJ("origin", GetTriggerUnit(), "WAR_STOMP")
        call DestroyEffect(GetLastCreatedEffectBJ())
    endif
    call RemoveLocation(Temp_Point)
endfunction

No special effect is played. Even if I remove the DestroyEffect line nothing happens.

- Mr_Bean

 

[Geries]

Give the path for the model. Like Abilities\\orc\\warstomp\\warstomp.mdx. That is not the correct path, i cant check path now..

 

[D3athM3at]

Few more tips: dont ever use red functions search for theyr native functions and use those and instead of location use x and y then you dont have to remove location

 

[Luorax]

Okay, thanks guys, I seem to have sorted it out. One more quick question: What is wrong with this:

function Leave_Area takes nothing returns nothing
    local location Temp_Point = GetUnitLoc(GetTriggerUnit())
    if (GetLocalPlayer() == Player (0)) then
        call DisplayTextToPlayer(Player(0), 0, 0, "Hi")
        call AddSpecialEffectTargetUnitBJ("origin", GetTriggerUnit(), "WAR_STOMP")
        call DestroyEffect(GetLastCreatedEffectBJ())
    endif
    call RemoveLocation(Temp_Point)
endfunction

No special effect is played. Even if I remove the DestroyEffect line nothing happens.

- Mr_Bean

This's how it should look like:

function Leave_Area takes nothing returns nothing
    //Use these instead of locals; reals're faster, and you don't have to destroy or null them
    local real x=GetUnitX(GetTriggerUnit())
    local real y=GetUnitY(GetTriggerUnit())
    //However they're not used anywhere in the function; I guess the location
    //was there because you wanted to create the effect at a certain point.
    
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(Player(0), 0, 0, "Hi")
        //Don't use those red functions, as someone's already mentioned it
        //They're there for GUI users, but they simply call these purple lines
        //so you can call them directly; it's faster.
        call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", GetTriggerUnit(), "origin"))
        //Yes, you can do this; you can destroy it immediately
        //Also, don't forget about the double backslash
    endif
endfunction

 

[Magtheridon96]

function Leave_Area takes nothing returns nothing
    //Use these instead of locals; reals're faster, and you don't have to destroy or null them
    local real x=GetUnitX(GetTriggerUnit())
    local real y=GetUnitY(GetTriggerUnit())
    //However they're not used anywhere in the function; I guess the location
    //was there because you wanted to create the effect at a certain point.
    
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(Player(0), 0, 0, "Hi")
        //Don't use those red functions, as someone's already mentioned it
        //They're there for GUI users, but they simply call these purple lines
        //so you can call them directly; it's faster.
        call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", GetTriggerUnit(), "origin"))
        //Yes, you can do this; you can destroy it immediately
        //Also, don't forget about the double backslash
    endif
endfunction

->

function Leave_Area takes nothing returns nothing
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(GetLocalPlayer(), 0, 0, "Hi") // GetLocalPlayer() should be faster than Player(0) since it takes no parameters (i think)
        //Don't use those red functions, as someone's already mentioned it
        //They're there for GUI users, but they simply call these purple lines
        //so you can call them directly; it's faster.
        call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", GetTriggerUnit(), "origin"))
        //Yes, you can do this; you can destroy it immediately
        //Also, don't forget about the double backslash
    endif
endfunction

 

[watermelon_1234]

function Leave_Area takes nothing returns nothing
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(GetLocalPlayer(), 0, 0, "Hi") // GetLocalPlayer() should be faster than Player(0) since it takes no parameters (i think)
        //Don't use those red functions, as someone's already mentioned it
        //They're there for GUI users, but they simply call these purple lines
        //so you can call them directly; it's faster.
        call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", GetTriggerUnit(), "origin"))
        //Yes, you can do this; you can destroy it immediately
        //Also, don't forget about the double backslash
    endif
endfunction

->

function Leave_Area takes nothing returns nothing
    local string path = "Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl"
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(GetLocalPlayer(), 0, 0, "Hi")
    else
        set path = ""
    endif
    call DestroyEffect(AddSpecialEffectTarget(path, GetTriggerUnit(), "origin"))
endfunction

Refer to this.

 

[Luorax]

function Leave_Area takes nothing returns nothing
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(GetLocalPlayer(), 0, 0, "Hi") // GetLocalPlayer() should be faster than Player(0) since it takes no parameters (i think)
        //Don't use those red functions, as someone's already mentioned it
        //They're there for GUI users, but they simply call these purple lines
        //so you can call them directly; it's faster.
        call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", GetTriggerUnit(), "origin"))
        //Yes, you can do this; you can destroy it immediately
        //Also, don't forget about the double backslash
    endif
endfunction

->

function Leave_Area takes nothing returns nothing
    local string path = "Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl"
    if (GetLocalPlayer()==Player (0)) then
        call DisplayTextToPlayer(GetLocalPlayer(), 0, 0, "Hi")
    else
        set path = ""
    endif
    call DestroyEffect(AddSpecialEffectTarget(path, GetTriggerUnit(), "origin"))
endfunction

Refer to this.

Huhh, sorry, did not pay attention, there's a GetLocalPlayer() call. I know that it causes desync, I simply... ignored that part of the script

@Magtheridon96 Read the comments. I told him that he doesn't need those locals, but I wanted to show him how to use it properly if he'd need to use a location.

 

[Troll-Brain]

Hmm, i'm not sure create/destroy an effect in a local block would desync, at least texttags don't and i would bet effects don't also, but i can't test it.

 

[Mr_Bean]

Hmm, i'm not sure create/destroy an effect in a local block would desync, at least texttags don't and i would bet effects don't also, but i can't test it.

I want to create the effect so it is visible for all players.

===================================

Another quick question:
How do I create a special effect attached to the origin of Temp_Unit (variable)? This is all that I want a function to do. I have to declare variables at the beginning of each function, but how would I do this without resetting Temp_Unit?

Thanks!

- Mr_Bean

 

[Pharaoh_]

If this Temp_Unit changes, you can also use it as a parameter

function Leave_Area takes unit u returns nothing
endfunction

Otherwise, just use

call DestroyEffect(AddSpecialEffectTarget("path", udg_Temp_Unit, "origin"))

 

[Mr_Bean]

Thanks. How would I call the function "Leave_Area" now that it takes unit Temp_Unit? If I say this, it gives an error:

• Custom script: call Leave_Area()

Thanks,

- Mr_Bean

 

[Pharaoh_]

If you use the unit as a parameter, you do not need the Temp_Unit anymore.
It would go like this:

function Leave_Area takes unit u returns nothing
    call KillUnit(u)
endfunction

(This was an example of how to use the parameter in the function)

How to call it (example #2):

• Trigger
• Events
  • Unit - A unit gains a level
• Conditions
• Actions
  • Custom script: call Leave_Area (GetTriggerUnit())

 

[Mr_Bean]

Awesome! Thanks so much for your help. Looks like I've got a lot to learn!

EDIT: If I had this script, how would I use custom scripts to call it?

function Movement_Speed takes unit Wisp returns nothing
    local real Temp_Real = GetUnitMoveSpeed(Wisp)
    call DisplayTextToPlayer(GetTriggerPlayer(), 0, 0, "Wisp movement speed: |cffffcc00" + (I2S(R2I(Temp_Real))) +"|r")
endfunction

Thanks,

- Mr_Bean

 

[mckill2009]

EDIT: If I had this script, how would I use custom scripts to call it?

• Custom script: call Movement_Speed(YOUR UNIT HERE)

 

[Mr_Bean]

Okay, thanks. I am trying now to create an effect on the unit Temp_Unit (variable) every 3 seconds. How would I write the custom script for this:

function Show_Unit takes unit Temp_Unit returns nothing
    call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Human\\Thunderclap\\ThunderClapCaster.mdl", Temp_Unit, "origin"))
endfunction

Thanks!

- Mr_Bean

 

[Pharaoh_]

You don't have to delete your posts, just edit them.

• Custom script: call Show_Unit (udg_Temp_Unit)

You won't need a parameter though, if you are going to reference a global variable.

Basically it's:
call FunctionName (parameter1, parameter2)
[(parameter1 & 2: if any)]

 

[Mr_Bean]

I am obviously doing something wrong. Here are my scripts:

function Setup takes nothing returns nothing
    local location Temp_Point = GetPlayerStartLocationLoc(Player(0))
    local unit Wisp = CreateUnitAtLoc(Player(0), 'ewsp', Temp_Point, bj_UNIT_FACING)
    call SelectUnitForPlayerSingle(Wisp, Player(0))
    call PanCameraToTimedLocForPlayer(Player(0), Temp_Point, 0)
    call RemoveLocation(Temp_Point)
endfunction

function Effect takes nothing returns nothing
    call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", Wisp, "origin"))
endfunction

Here are my triggers for calling them:

• Map Setup
  • Events
    • Map initialization
  • Conditions
  • Actions
    • Visibility - Disable fog of war
    • Visibility - Disable black mask
    • Custom script: call Setup()

• Effect
  • Events
    • Player - Player 1 (Red) types a chat message containing -effect as An exact match
  • Conditions
  • Actions
    • Custom script: call Effect(Wisp)

What am I doing wrong? It calls Map Setup fine, but I am having trouble with Effect. How do I set global variables (for example, a player chooses a hero and I set the variable: Hero[0] = their hero for the whole game)? Also, I know the parts in red writing are bad - what are their alternatives that I should use? Thanks!

- Mr_Bean

 

[Pharaoh_]

Your 'Effect' function doesn't take parameters, but you force it to, when calling it. Change the function to:

function Effect takes unit Wisp returns nothing

Also, what's Wisp? You should define the unit you want; if you used (Triggering unit), it should be:

• Tr
• Events
  • Unit - A unit dies
• Conditions
• Actions
  • Custom script: call Effect (GetTriggerUnit())

However, if you use that event, you don't need parameters, as you have probably have the unit stored in some global variable, called Temp_Unit for example.

• Effect
• Events
  • Player - Player 1 (Red) types a chat message containing -effect as An exact match
• Conditions
• Actions
  • Custom script: call Effect()

and the Jass:

function Effect takes nothing returns nothing
    call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", udg_Temp_Unit, "origin"))
endfunction

 

[Mr_Bean]

Okay. How would I set the global variable then?

Thanks,

- Mr_Bean

 

[Pharaoh_]

• Set Temp_Unit = <Some unit>

It depends on what you want to do actually. If you want the Effect() function to work for only one unit, there's no reason to use a parameter within it. If it works for multiple units, you should add a parameter to it.

 

[Mr_Bean]

I want to set the last created unit to Hero[1] so that the variable is stored for the whole game. How do I do this with JASS?

- Mr_Bean

 

[Bannar]

Using your previous function (a bit improved one) it looks somewhat like:

function Setup takes nothing returns nothing
    local player p = Player(0)
    local real x = GetStartLocationX(GetPlayerStartLocation(p))
    local real y = GetStartLocationY(GetPlayerStartLocation(p))
    set udg_Hero[1] = CreateUnit(p, 'ewsp', x, y, bj_UNIT_FACING)
    //Select the unit plus Pan Camera
    if (GetLocalPlayer() == p) then
        call ClearSelection()
        call SelectUnit(udg_Hero[1], true)
        call PanCameraToTimed(x, y, 0)
    endif
    set p = null
endfunction

 

[Pharaoh_]

• Set Hero[1] = (Last created unit)

function Effect takes nothing returns nothing
    call DestroyEffect(AddSpecialEffectTarget("Abilities\\Spells\\Orc\\WarStomp\\WarStompCaster.mdl", udg_Hero[1], "origin"))
endfunction

 

[Mr_Bean]

Using your previous function (a bit improved one) it looks somewhat like:

function Setup takes nothing returns nothing
    local player p = Player(0)
    local real x = GetStartLocationX(GetPlayerStartLocation(p))
    local real y = GetStartLocationY(GetPlayerStartLocation(p))
    set udg_Hero[1] = CreateUnit(p, 'ewsp', x, y, bj_UNIT_FACING)
    //Select the unit plus Pan Camera
    if (GetLocalPlayer() == p) then
        call ClearSelection()
        call SelectUnit(udg_Hero[1], true)
        call PanCameraToTimed(x, y, 0)
    endif
    set p = null
endfunction

THANK YOU SO MUCH!!! If I put the quoted script in JASSCraft, it says that there are undeclared variables on lines 6 and 15. Must I just ignore this?

Thanks again,

- Mr_Bean

 

[mckill2009]

the undeclared *thing* is the udg_Hero[1] so you should make the variable for it...
be warned also that you cant call just call it from custom script unless you put that function in a library OR the map header...

 

[Mr_Bean]

the undeclared *thing* is the udg_Hero[1] so you should make the variable for it...
be warned also that you cant call just call it from custom script unless you put that function in a library OR the map header...

How would I make variables for them? With the trigger editor? All my JASS is in the map header.

- Mr_Bean

EDIT: I put the variables in the trigger editor and it works! Thanks again!