Re: unexpected unmodified variable

[Ray Andrews <rayandrews@eastlink.ca>]

On 2022-10-07 13:00, Bart Schaefer wrote:
> ... which might just be the most impenetrable bit of computer 
> bafflegab I've ever read, I can't get past the first sentence.
> Seriously?  This is all using phrases that refer to concepts appearing
> elsewhere throughout the zsh manual.
True ... which makes the manual hard to understand.  It's a language 
unto itself.   What would be helpful is some sort of introduction to 
zsh-speak.  Mind, I expect all the shells have about the same jargon.  
But believe me, when you don't know the lingo it's impenetrable.
>
> Oh.  Given the way you wrote func2, if you remove the return statement
> there are NO math expressions in func2 at all, so $(( func2() )) is
> [except for side-effects] a no-op, and the assignment in var=$((
> func2() )) is just skipped, leaving the previous value of $var
> unchanged.

Ah! ... yes, why would it change? nothing has touched it.  I was 
expecting func2 to somehow cough up a null value setting 'var=0' but 
it's not illogical that it coughs up ... nothing ... therefore there is 
no assignment and 'var' does not change.  I get it.


> "Local" text substitution is what ordinary $param references are for
> ... $(...) specifically means to use processes and pipes.  That said,
> a still-missing feature in zsh is the ability to tie a function to a
> variable so that referencing the variable as $foo invokes the function
> that's tied to it, to produce the effect you're asking for.  Ksh has a
> syntax for that.
>
Well you'd know.  Anyway as usual the functionality I was looking for is 
there even if it didn't look like I expected.  By now I should have a 
permanent understanding of this stuff not keep relapsing.