Extending $0 - $9 and $R0 - $R9

Afrow UK
16th February 2003 20:50 UTC

Extending $0 - $9 and $R0 - $R9
I have simply run out of all the $x and $Rx functions in my script, and am wondering if you can make up new ones that can be used in StrCpy, ReadINIstr etc

I know you can...
!define TEMP1 "$0"
StrCmp ${TEMP1} $0 "" +2
...but that uses up $0

-Stuart

kichik
16th February 2003 21:26 UTC

Defining TEMP1 as $0 is nothing more but telling the compiler to replace every ${TEMP1} it sees with $0, it doesn't create a new variable.

The best way to clear up some variables for usage is to push them to the stack and when you are finished with them pop them back. For example:

Push$0

Push$1

># use $1 and $0 here...

>Pop $1

Pop$0

># $0 and $1 are same as before the push now

Another way you might want to try is to read data from INI files or the registry only when you need it and not to keep it ready from the beginning. This also applies to section selections (use SectionGetFlags instead of setting a variable to 1 when the section executes).

Afrow UK
16th February 2003 22:25 UTC

Thanks

I'll have a look into where I can push and pop them around!
Here is the script...

http://myweb.tiscali.co.uk/afrowuk/map-compiler.nsi

-Stuart

rainwater
17th February 2003 01:27 UTC

Well, for functions, its always best to Push all the variables on the stack that you are going to use. Then when the function is over, pop them back in (making sure you use the right order). Then you will still have every variable available outside of the function since that function takes care of any previous variables that were used.

treaz
21st March 2003 22:58 UTC

Hi,

I guess I am a little slow at this pushing and popping idea.

Can someone explain a little more on when to use PUSH and when to use POP?

Do I Pop or Push a variable when I wish to know the value of that variable?

Thanks.
:)

Joost Verburg
22nd March 2003 11:20 UTC

Push adds a value to the stack, Pop removes one and sets the variable.

For example, the value of $0 is 123.

Now you are going to call the function bla:

Function bla

  Push $0 ;123 added to the stack

    ...the function can use $0...

  Pop $0 ;Remove 123 from the stack and set $0 back to 123

FunctionEnd

After calling the funtion, the variables contain the same value as before.

Note the order when using multiple variables (last-in first-out):

Function bla

  Push $0
  Push $1

     ...code...

  Pop $1
  Pop $0

FunctionEnd

Joel
22nd March 2003 14:38 UTC

And how can we, for example, since $9 is for the Startmenu, use it once and then "empty" the value so startmenu use it.
In my case I use $9 for my name in the script; but I copy the value:


StrCpy $9 "${MUI_PRODUCT}"

So the startmenu recognize.

Joost Verburg
23rd March 2003 11:23 UTC

The first option is to define MUI_STARTMENUPAGE_VARIABLE with another variable ($8 for example), so another variable will be used.

If you have to use all 20 variables, you can also Push/Pop it if you want to use the variable temporary.

Push ${MUI_STARTMENUPAGE_VARIABLE}
  ...code...
Pop ${MUI_STARTMENUPAGE_VARIABLE}

Why are you using a variable for the name? The name is always the same, so you can use a define.

Joel
23rd March 2003 15:02 UTC


!define MyName "Dude"

I already have done that :D
But checking my script, I forgot that
I'm using the System plugin to detect RAM and "stole" $9.
Yeah! I'll "Pop it" :up:

mlm
22nd April 2003 04:42 UTC

Clearing the stack...
Is there a way to clear the stack and start over?

mlm(aka digitalda)

virtlink
22nd April 2003 10:41 UTC

Here is an article about the stack: http://nsis.sourceforge.net/archive/...52&instances=0.

Try this code (may contain errors, couldn't test it) to clear the stack:

LoopAgain:

>Pop $R9

IfErrors Done LoopAgain

Done:

This will use the $R9 variable.