Re: [Help-bash] Updating global variable from recursing function.

[Frans de Boer]

On 04/02/2012 10:33 PM, Frans de Boer wrote:
> On 04/02/2012 09:17 PM, Greg Wooledge wrote:
> > On Mon, Apr 02, 2012 at 09:08:12PM +0200, Frans de Boer wrote:
> > > Strange, it is working fine, the counter is incremented but the result
> > > is never propagated to the real global variable, as shown by the bash -x
> > > output.
> >
> > imadev:~$ cat foo
> > #!/bin/bash
> >
> > foo() {
> > local i=7
> > if ((i> max)); then max=$i; fi
> > }
> >
> > max=0
> > foo
> > echo "max is $max"
> >
> > imadev:~$ ./foo
> > max is 7
> >
> >
> > > Every time the function returns to the caller, the iHiMDirNest is
> > > restored to the level it was before being calling.
> >
> > That suggests that the variable is in fact local, in some scope or
> > other. Are you sure you showed us the *uppermost* scope? For example,
> > this would do it:
> >
> > imadev:~$ cat bar
> > #!/bin/bash
> >
> > bar() {
> > local max
> > foo "$@"
> > }
> >
> > foo() {
> > local i=7
> > if ((i> max)); then max=$i; fi
> > echo "inside foo, max=$max"
> > }
> >
> > max=0
> > bar
> > echo "at global scope, max is $max"
> >
> > imadev:~$ ./bar
> > inside foo, max=7
> > at global scope, max is 0
>
> I stand corrected:
> #!/bin/sh
> #
> declare -i iTest1=0
> declare -i iMax=7
>
> function recursetest () {
>
> iTest1=$((iTest1+1))
> if (( iTest1 < iMax )); then recursetest; fi
> }
>
> function testcaller () {
> recursetest
> }
>
> echo "1 - recursetest=$iTest1"
> testcaller
> echo "2 - recursetest=$iTest1"
> ------------------
> Is producing the right result while using [[ does not.
> That leaves a puzzle for me to check why the trace showed correct
> results before a return.
>
> Anyhow, thanks for pointing me in the right direction.
>
> Regards, Frans.
As a final, I changed all [[ into (( when it was a pure integer 
comparison in my script and all is working well. I think it is also the 
source of some other problems I encountered with recursion of deeper 
nesting of functions.

Seems, I did not understood the difference between [[ and (( in string 
and integer comparisons. Back to school to study more :\

Again thanks,
Frans.