Re: how to force a second variable expansion?

[Robert P. J. Day]

On Tue, 8 Mar 2005, Paul D. Smith wrote:

> %% "Robert P. J. Day" <address@hidden> writes:
>
>   rpjd>   i have a normally-straightforward macro to process subdirectories:
>
>   rpjd>     define do-subdirs
>   rpjd>     @for dir in ${SUBDIRS} ; do                          \
>   rpjd>       ${MAKE} CF=$${$${dir}_CONFIG_FILE} -C $@ ; \  (clearly wrong)
>   rpjd>                 ??????????????????????????
>   rpjd>     done
>   rpjd>     endef
>
> Of course, this cannot work.

oh, i'd figured that out already, that's why i wrote that it was
"clearly wrong" -- i just wanted to put *something* in there to give
an idea of what i was trying to do, even if it was hopelessly
incorrect. :-)

> It's NEVER possible for the shell to "query back" to the parent make
> process and ask it to resolve some variable, so there's no way you
> can evaluate a MAKE variable like xx_CONFIG_FILE where the "xx"
> value is contained in a SHELL variable like $dir.

i finally twigged on why this wasn't going to work, exactly as you
explained it.  dang.  obviously, i might get this to work if i can
have all substitution/variable expansion done with the make variables
before invoking any shell commands.

i'll play with this some more.  thanks again.

rday