[JASS] Stacks

[Tigershark]

Is there already somewhere a "Stack" data structure for JASS that someone has written and is good?

I was about to try to write my own, but I thought I'd ask the pros...

thanks

 

[spiwn]

What is a "stack"?
Do you mean HoMM type of stacks?

 

[Tigershark]

I mean a "LIFO" stack, where I can push a data type on to it, pop a data type off of it, or peek to see what's on it.

Although, since jass is no where near supporting generics, i figure i should just make my own (since i need a stack for locations.) Let me ask you though, (assuming I make it proper), is this the type of thing to be added to the JASS resources?

 

[HINDYhat]

If I understood correctly, well... people don't really use systems for this. They just inline all needed code required to make a stack. It's used quite often:

// stacking some data:
set ARRAY[COUNT] = data
set COUNT = COUNT + 1

// removing data from the stack:
set COUNT = COUNT - 1
set ARRAY[thisIndex] = ARRAY[COUNT]

But I probably misunderstood you...

 

[spiwn]

I have no idea what you are talking about(maybe I had to flunk from school a little bit less)
I just asked so that I would learn what stacks are(and I have learned) and if by any chance I have seen something like that, to point you.
But I have not. And I believe such a thing has not been done.
But aren't stacks like arrays, but with some "sorting".

 

[HINDYhat]

Yes, and that's exactly what I wrote. Notice that when I remove an object from the stack, the last object is moved to that position? That's a sort

 

[spiwn]

Yes, that is some sorting.
Another possibility would be to move all the elements after thisIndex 1 index ahead. But that would be slower.
P.s. When I posted, I did not know you have posted before me

 

[HINDYhat]

Obviously, except my method is 13298129038219 times better than that. There's an infinite amount of possibilities. Mine is just the most efficient in this case...

 

[Tigershark]

I was referring to the Data Structure of a stack...basically has an array backing, but the concept is that you Push something onto the Top of the stack, and you can only access the Top of a stack, via a Peek method (just gives you that item) or a Pop call (which not only returns it but also removes it from the stack...now whether the implementation actually removes it or not, that's up to the implementor). Thus it exhibits LIFO characteristics (Last In, First Out).

and this is a stack for locations that i'm just putting in my header script

struct locStack
    location array a[100]
    // the Top Of Stack represents our empty position
    integer tos = 0
endstruct

function pushStack takes locStack s, location loc returns nothing
    if( s.tos <= 99 ) then
        set s.a[s.tos] = loc
        set s.tos = s.tos + 1
    else
    endif
endfunction

function popStack takes locStack s returns location
    if( s.tos >= 1 ) then
        set s.tos = s.tos - 1
        return s.a[s.tos]
    else
        return null
    endif
endfunction

function peekStack takes locStack s returns location
    return s.a[s.tos]
endfunction

if you do see something wrong, please let me know. but this should cover it...sorry for the confusion lulz.

Edit: lol quick edit too. forgot to check to make sure they don't go over the 100 size...

 

[Freiddie]

That's a neat way of making a Stack data-type. Hmm... So I guess a Queue data-type could be something very similar to this...

 

[spiwn]

Reading tutorials and manuals is a good idea:

type stackarray extends integer array [20]

struct stack
   private stackarray V
   private integer N=0

   method Create takes nothing returns stack
    local stack s=stack.create()
       set s.V=stackarray.create()
       if (s.V==0) then
           debug call BJDebugMsg("Warning: not enough space for stack array")
           return 0
       endif
   endmethod

   method push takes integer i returns nothing
       if (this.N==stackarray.size) then
           debug call BJDebugMsg("Warning: stack is full")
       else
           set this.V[this.N]=i
           set .N = .N +1 //remember this syntax is valid as well
       endif
   endmethod

   method pop takes nothing returns nothing
       if (this.N>0) then
           set this.N=this.N-1
       else
           debug call BJDebugMsg("Warning: attempt to pop an empty stack");
       endif
   endmethod

   method top takes nothing returns integer
       return .V[.N-1]
   endmethod

   method empty takes nothing returns boolean
       return (.N==0)
   endmethod

   method onDestroy takes nothing returns nothing
       call this.V.destroy()
   endmethod
endstruct

Directly copied from JassHelper Manual

 

[Freiddie]

You can use methods in vJASS? You can use private fields? I didn't know that. Where is this JassHelper manual?

 

[spiwn]

In the JassHelper folder, which is inside the JassNewGenPack "install" folder.

 

[Freiddie]

Thanks.