Converting nothing to integer

05-28-2009, 01:18 AM	#1
Deaod	Yes, this is possible. You can spawn data out of nowhere. JASS: function N2I takes nothing returns integer return return 0 endfunction Problem currently is: no JASS parser allows that function, although WC3 parses it without error. Also, can anyone explain to me where that integer is coming from? I suspect it reads a specific register of the CPU but im not too sure (if at all).

05-28-2009, 02:25 AM	#2
MaD[Lion]	weird u really get an integer?, cus when return stands alone i think it just simply exit the function. maybe it returns the function pointer? haha

05-28-2009, 05:13 AM

azlier

True, that doesn't compile (or pass through Jass parsers, I should say), but this does.

JASS:

function Nothing takes nothing returns nothing
    return
    return
endfunction

function N2I takes nothing returns integer
    return Nothing()
    return 0
endfunction

For me, it returns 1049284 on the first display and 0 on all new displays.

EDIT: It seems to return the first available handle slot, but then returns 0 on next calls...

What means this does?

05-28-2009, 05:16 AM

Vexorian

Quote:

Originally Posted by azlier

True, that doesn't compile, but this does.

JASS:

function Nothing takes nothing returns nothing
    return
    return
endfunction

function N2I takes nothing returns integer
    return Nothing()
    return 0
endfunction

For me, it returns 1049284 on the first display and 0 on all new displays.

THAT compiles?

I guess it would return the top of the stack or a random register.

05-28-2009, 05:29 AM

azlier

It reacts differently to whatever was called before it. I happened to do some handle creation, and set a boolean to false.

If I move it after, say, a text message, it returns 0 no matter what.

Aye, it is rather unpredictable.

Jass is quite the little monster.

EDIT: No, wait! I cracked it! It returns whatever the last called function did. The text message returned nothing, so 0.

Here are my test functions:

JASS:

function Nothing takes nothing returns nothing
    return
    return
endfunction

function N2I takes nothing returns integer
    return Nothing()
    return 0
endfunction

function C2I takes code c returns integer
    return c
    return 0
endfunction

function H2I takes handle h returns integer
    return h
    return 0
endfunction

function TestFunc takes nothing returns integer
    return 1337
    return 1337
endfunction

JASS:

call CreateTrigger()
call BJDebugMsg("Value of nothing: " + I2S(N2I()))
call BJDebugMsg("Value of new handle: " + I2S(H2I(CreateGroup())))
call TestFunc()
call BJDebugMsg("Value of nothing: " + I2S(N2I()))
call BJDebugMsg("Code value of nothing: " + I2S(C2I(function Nothing)))
call BJDebugMsg("Code value of N2I: " + I2S(C2I(function N2I)))

05-28-2009, 07:38 AM	#6
PipeDream	There's a bytecode for setting the return value which only occurs before the return opcode if you return a value. It's actually a bytecode for copying one register to another, but the destination register is always 0, which isn't, as far as I remember, used for anything else. Presumably this will go away in the next patch anyway.

05-28-2009, 01:25 PM

Vexorian

Quote:

Presumably this will go away in the next patch anyway.

You have no idea... (ok, maybe YOU do)