How to have function local variable but must behave just a simple one

How to have function local variable but must behave just a simple one

[Budi]

How to have function local variable but must behave just a simple /
plain variable which is retaining its value all the time, no matter
how many times exit and enter the function

Re: How to have function local variable but must behave just a simple one

[Roman Perepelitsa]

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On Sat, 26 Aug 2023 at 10:26, Budi <budikusasi@gmail.com> wrote:

> How to have function local variable but must behave just a simple /
> plain variable which is retaining its value all the time, no matter
> how many times exit and enter the function


Sort of like a function-scoped static variable in C?

    int counter() {
      static int n = 0;
      return ++n;
    }

Zsh doesn't have the equivalent. You'll have to use a global parameter.

Roman.

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Re: How to have function local variable but must behave just a simple one

[Bart Schaefer]

On Sat, Aug 26, 2023 at 12:34 AM Roman Perepelitsa
<roman.perepelitsa@gmail.com> wrote:
>
> Zsh doesn't have the equivalent. You'll have to use a global parameter.

More generically speaking, shells typically use dynamic scoping rather
than lexical scoping, which means a variable only persists until the
scope where it is declared finishes, and while it persists it is
available to all deeper scopes.  The zsh/param/private module changes
some of the availability rules, but nothing changes the persistence.

Re: How to have function local variable but must behave just a simple one

[Ray Andrews]

On 2023-08-26 13:26, Bart Schaefer wrote:
> On Sat, Aug 26, 2023 at 12:34 AM Roman Perepelitsa
> <roman.perepelitsa@gmail.com> wrote:
>> Zsh doesn't have the equivalent. You'll have to use a global parameter.
Why not have a global variable and then just make the assignment to a 
local variable at each call of the function and update the global when 
and where desired or let the local variable just die otherwise?  I 
suspect I don't really understand the problem.

Re: How to have function local variable but must behave just a simple one

[Roman Perepelitsa]

On Sat, Aug 26, 2023 at 10:39 PM Ray Andrews <rayandrews@eastlink.ca> wrote:
>
> On 2023-08-26 13:26, Bart Schaefer wrote:
> > On Sat, Aug 26, 2023 at 12:34 AM Roman Perepelitsa
> > <roman.perepelitsa@gmail.com> wrote:
> >> Zsh doesn't have the equivalent. You'll have to use a global parameter.
>
> Why not have a global variable [...]

Indeed, given that in zsh there are no function-scoped parameters that
outlive an invocation of the function, Budi will have to use a global
parameter and take necessary precautions to ensure the name of the
parameter does not clash with other globals.

Roman.

Re: How to have function local variable but must behave just a simple one

[Ray Andrews]

On 2023-08-26 13:58, Roman Perepelitsa wrote:
>
> Indeed, given that in zsh there are no function-scoped parameters that
> outlive an invocation of the function, Budi will have to use a global
> parameter and take necessary precautions to ensure the name of the
> parameter does not clash with other globals.
>
> Roman.

I'm puzzled as to what the problem really is from a practical point  of 
view.  Easy enough to create a 'safe' name, no?  I suppose for  tidiness 
sake one might not want variables specific to only one function to be 
global, but there's zillions of that sort of variable already so one 
lives with that rather easily. And this is universal across all shells, 
yes?  I have a set of local variables that I need to survive reboot, so 
I write 'em to a file which is reread on startup.  That would work for 
Budi, but again it seems like there's not really a big problem.  (Mind, 
I have a long history of seeing problems where there is no problem ;-)

Re: How to have function local variable but must behave just a simple one

[Roman Perepelitsa]

On Sat, Aug 26, 2023 at 11:11 PM Ray Andrews <rayandrews@eastlink.ca> wrote:
>
> On 2023-08-26 13:58, Roman Perepelitsa wrote:
> >
> > Indeed, given that in zsh there are no function-scoped parameters that
> > outlive an invocation of the function, Budi will have to use a global
> > parameter and take necessary precautions to ensure the name of the
> > parameter does not clash with other globals.
> >
> > Roman.
>
> I'm puzzled as to what the problem really is from a practical point  of
> view.

You aren't missing anything.

Roman.

Re: How to have function local variable but must behave just a simple one

[Budi]

Aim to have a global var. name protected, it's in PROMPT inevitably
require full private protective level from interactive-shell actions


use below to understant what it means

https://github.com/abdulbadii/smart-directories-navigation