On Wed, 6 Aug 2008, Dejan Muhamedagic wrote:
> On Wed, Aug 06, 2008 at 02:42:10PM +0100, David Lee wrote:
> > > [...]
> > > + local rnd="$RANDOM"
> > > [...]
> >
> > That "local ..." construction: is that a true Bourne feature? In this
> > "shellfuncs" area, we need to be as portable as possible, avoiding
> > "bash-isms". (I think we accept that some particular OCFs could well be
> > "bash" these days, but these utility functions, shared across all OCFs,
> > need to be Bourne.)
> >
> > [...]
>
> The "local" keyword is I think in the POSIX standard. Is there a
> platform with shell which doesn't comply with the POSIX at least?
Sadly, yes. For instance I have just tested 'sh' on Solaris 8, 9 and 10
(Sun's currently supported releases): 'local' fails on all.
How to progress? Conventions for such local variables (i.e. variables
where the programmer's intention is to limit the scope to the block) to
avoid namespace clashes include using a leading "_" in the name (avoid
clash with 'main script' variables which don't use leading "_") and having
the name somehow reflect the function name (avoid clash amongst different
functions). For instance:
var1=XXX
var2=YYY
my_function() {
_mf_v1=$1
_mf_v2=$2
}
your_function() {
_yf_v1=$1
_yf_v2=$2
}
Pragmatically most sh-programming things are fine with such conventions;
the quantities of potentially interacting functions are manageable by
adoption of such conventions.
Hope that helps.
Just to confirm: I'm happy that individual OCFs be 'bash' (so long as
they say "#!/bin/bash", not "!#/bin/sh"). And they can happily use
'local' withing themselves. But what we're talking about here are the
utility functions shared by all OCFs. So (sadly but realistically) I
think there has to be an element on 'lowest common denominator' just in
this particular context.
Does that seem OK?
Best wishes.
--
: David Lee I.T. Service :
: Senior Systems Programmer Computer Centre :
: UNIX Team Leader Durham University :
: South Road :
: http://www.dur.ac.uk/t.d.lee/ Durham DH1 3LE :
: Phone: +44 191 334 2752 U.K. :
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