Re: make: sysV subst with variables

[David Laight <david%l8s.co.uk@localhost>]

On Thu, Jun 02, 2011 at 05:51:01PM +0000, David Holland wrote:
> It does prohibit the case
> 
>    MOD=tl:
>    ${FOO:${MOD}S/^/blah/}
> 
> from above, but I can't think of any particular reason we should cater
> to this when it's just as reasonable to write
> 
>    MOD=tl
>    ${FOO:${MOD}:S/^/blah/}

I can think that it might be useful to generate a list of modifiers
and then apply it - when the above translation can't be done.

    MOD=tl:
    MOD+=S/^/blah/
    ${FOO:${MOD}}

might be more reasonable - but probably suffers if 'blah' is actually a variable
that contains '/' since it probably expanded at the wrong time.

Or is the expansion of ${MOD} in my example one of the few places where make
doesn't do a recursive expansion?

        David

-- 
David Laight: david%l8s.co.uk@localhost