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Re: [Groff] \V[envvar]: is/was there a "does-exist" concruent to 'getenv

From: Werner LEMBERG
Subject: Re: [Groff] \V[envvar]: is/was there a "does-exist" concruent to 'getenv(VAR) != NULL'?
Date: Wed, 14 Jan 2015 08:22:53 +0100 (CET)

> i really wonder because all i can do is
>   .if !'\V[GROFF_NO_MDOCMX]'' ...
> but what i really would like to do is rather
>   .if !d \V[GROFF_NO_MDOCMX]
> so to be synchronous with $GROFF_NO_SGR.  Well i am, but only on
> grotty(1) level, not in the macros, which is odd.
> Wouldn't it be, even more, natural to be able to use "d" for that?

\V always returns a string.  If the environment variable is not
defined, it returns an empty string.

If `GROFF_NO_MDOCMX' is not set, your code

  .if !d \V[GROFF_NO_MDOCMX]

expands to

  .if !d ""

which is meaningless.

It might be possible to create another interface to environment
variables, but I strongly doubt that it is worth the trouble.


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