Re: Understanding internal variable scope

[Robert E. Griffith]

FYI, I think I answered these questions on my own today by printing the 
shell_variables context stack out and then calling the builtin from 
various context -- file global vs in a function and main script vs 
sourced script vs sourced from inside a function.

> 1) I find that when my loadable builtin is called from a bash 
> function, sometimes... create a local variable... does not work. 
My stupid mistake. I had forgotten that I started calling the builtin 
from a bash wrapper function so the variables were being made in that 
scope and then immediately went out of scope soon after the builtin 
returned.

> 2) There seems to be a difference between sourcing a script at global 
> scope
I see now the issue is in weather the -g is specified when using 
"declare" at the global scope of an sourced script. Without the -g if 
source is called from a function, declare is in the context of that 
function so it creates a local variable that will go out of scope with 
the function. With -g it puts in in the global scope regardless of 
whether there is a function variable context.

--BobG


On 5/28/22 10:36, Robert E. Griffith wrote:
> I would like to understand better the internal variable scopes in the 
> bash source code. Do you know of any documentation or past emails I 
> can read on it? I am pretty familiar with the code now but I think I 
> have some misconceptions because sometimes functions do not act like I 
> expect. Maybe the temporary scope is not quite like I think it is.
>
> In particular, I have two issues that I dont understand.
>
> 1) I find that when my loadable builtin is called from a bash 
> function, sometimes the following code works to create a local 
> variable in the calling function and sometimes it does not. If I do 
> "local myVariableName" before calling the builtin, it always receives 
> hte value.
>
>    bind_variable_value(make_local_variable("myVariableName",0), 
> "SomeValue..., 0)
>
> 2) There seems to be a difference between sourcing a script at global 
> scope as opposed to sourcing it from inside a bash function but I cant 
> quite pin it down. Sometimes variables declared in the global scope 
> "declare <myvar>" of a sourced script do not exist after sourcing the 
> script but functions from the script always do.
>
> --BobG