Kirill Smelkov wrote:
> On Tue, Jan 06, 2009 at 09:32:03PM +0100, martin f krafft wrote:
> > I find this very confusing. Why not simply
> >
> > TG_PAGER="${GIT_PAGER:-}"
> > TG_PAGER="${TG_PAGER:-$PAGER}"
> >
> > ?
>
> I find it confusing too, but this is needed because they usually do
> something like this
>
> $ GIT_PAGER='' <some-git-command>
>
> to force it to be pagerless.
[...]
> So I think it would be better to preserve the same semantics for `tg
> patch` callers, though it's a pity that it's hard (maybe I'm wrong ?) to
> see whether an env var is unset.
Admittedly I haven't really studied your patch, but the ${} constructs
can in fact tell empty from unset:
$ EMPTY=
$ unset UNDEFINED
$ echo ${UNDEFINED-foo}
foo
$ echo ${UNDEFINED:-foo}
foo
$ echo ${EMPTY-foo}
$ echo ${EMPTY:-foo}
foo
'man bash' indeed says
When not performing substring expansion, bash tests for a parameter
that is unset or null; omitting the colon results in a test only for
a parameter that is unset.
So I suppose you could use
${GIT_PAGER-${PAGER-less}}
or similar.
--
Thomas Rast
trast@{inf,student}.ethz.ch
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