Re: [PATCH 04/16] Makefile: move Perl-only variable assignments under !NO_PERL

[Junio C Hamano <gitster@pobox.com>]

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

> -# Used for substitution in Perl modules. Disabled when using RUNTIME_PREFIX
> -# since the locale directory is injected.
> -perl_localedir_SQ = $(localedir_SQ)
> -

So, we used to unconditionally define this even if we had NO_PERL;
the patch is going to move it inside "ifndef NO_PERL", which makes
sense.

>  ifndef NO_PERL
> -PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
>  PERL_DEFINES =
>  PERL_DEFINES += $(PERL_PATH_SQ)
>  PERL_DEFINES += $(PERLLIB_EXTRA_SQ)
> @@ -2305,16 +2300,15 @@ PERL_DEFINES += $(RUNTIME_PREFIX)
>  PERL_DEFINES += $(NO_PERL_CPAN_FALLBACKS)
>  PERL_DEFINES += $(NO_GETTEXT)
>  
> -# Support Perl runtime prefix. In this mode, a different header is installed
> -# into Perl scripts.
> +# Under RUNTIME_PREFIX we inject a header into the Perl scripts; If
> +# NO_GETTEXT is not defined we'll make use of the localedir.

 * The second sentence after ';' should not begin with capital.  

 * "if X we do Y" wants a comma before the latter sentence.

 * "if NO_FOO is not defined" has too many negations.

Taking them together, I wonder if this would be more readable.

    ... into the Perl scripts; unless NO_GETTEXT is defined, we'll
    make use of ...

>  ifdef RUNTIME_PREFIX
> -
>  PERL_HEADER_TEMPLATE = perl/header_templates/runtime_prefix.template.pl
> -
> -# Don't export a fixed $(localedir) path; it will be resolved by the Perl header
> -# at runtime.
> -perl_localedir_SQ =

Is it a good idea to lose this?  We would get affected by a stray
environment variable of the same name without it, no?

> +ifndef NO_GETTEXT
> +perl_localedir_SQ = $(localedir_SQ)
> +endif


> +else

This "else" pairs with... ah, RUNTIME_PREFIX.  And of course we will
use the "fixed" variant only when RUNTIME_PREFIX is not in use.

> +PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
>  endif

Nice. now we have one HEADER_TEMPLATE definition on each branch
between "using runtime-prefix" and "not using runtime-prefix", which
makes sense.