Gentoo Archives: gentoo-devhelp

From: Mike Frysinger <vapier@g.o>
To: gentoo-devhelp@l.g.o
Subject: Re: [gentoo-devhelp] Re: Re: LINGUAS vs LANGUAGES
Date: Thu, 13 Aug 2009 19:28:53
In Reply to: [gentoo-devhelp] Re: Re: LINGUAS vs LANGUAGES by Steven J Long
On Saturday 01 August 2009 11:22:41 Steven J Long wrote:
> Mike Frysinger wrote: > > On Tuesday 21 July 2009 06:13:25 Steven J Long wrote: > >> Nikos Chantziaras wrote: > >> > Thanks. I ended up doing it this way, though with only one loop in > >> > src_install(), which seems to be a bit more efficient and shorter: > >> > > >> > > >> > LANGUAGES="de" > >> > for i in ${LANGUAGES}; do > >> > IUSE="${IUSE} linguas_${i}" > >> > done > >> > >> Just on a side-note (not saying it's how you want to do this one), this > >> is something that BASH arrays are nice for (saving another loop): > >> $ foo=(bar baz quux) > >> $ echo "prefixed: '${foo[*]/#/pfx_}'" > >> prefixed: 'pfx_bar pfx_baz pfx_quux' > > > > printf would probably be better as it is typically a shell builtin and it > > doesnt require use of arrays/uncommon syntax. > > media-gfx/exiv2/exiv2-0.18.ebuild: > > IUSE_LINGUAS="de es fi fr pl ru sk" > > IUSE="${IUSE} $(printf 'linguas_%s ' ${IUSE_LINGUAS})" > > Doh, forgot about printf. (We have alias print="printf '%s\n'" in our lib > code which comes in handy too.) Nice one. > > The only issue with the above is that it requires a subshell; forking isn't > cheap (especially on Interix/cygwin/doze) and in general it's considered a > bit lame (at least amongst the ##bash old-timers that I bump heads with) to > need forking in BASH, though ofc not in SH, which is why it might not be > the best here, since the metadata generation phase is a restricted subset > of SH, leave alone BASH, at least aiui.
forks are cheap on any sane *nix box, and subshells/builtins are better than external programs. i'm pretty sure the overhead here tends to be less than the overhead of running for loops, especially as the LINGUAS gets bigger. -mike


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Subject Author
[gentoo-devhelp] Re: Re: Re: LINGUAS vs LANGUAGES Steven J Long <slong@××××××××××××××××××.uk>