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On Mon, 08 Oct 2007 13:45:04 +0200 |
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"Marijn Schouten (hkBst)" <hkBst@g.o> wrote: |
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|
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> |
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> Marius Mauch wrote: |
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> >>> "Marijn Schouten (hkBst)" <hkBst@g.o>: |
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> >>>> I imagine there are a lot more cases where the simple on/off |
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> >>>> system we have now is suboptimal. I could be wrong of course. |
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> >>>> Please comment. |
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> >>> This key=value systems sounds interesting. Another use could be |
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> >>> the choice between xulrunner, seamonkey, firefox. |
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> > |
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> > We already have this with USE_EXPAND. Not exactly the same syntax, |
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> > but I don't see a terrible problem in that, and we don't have to |
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> > fix all three trillion related tools to handle it. Unless you can |
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> > come up with a case that can't be handled with USE_EXPAND. |
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> |
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> No, USE_EXPAND is only a way to abbreviate use flags with a common |
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> substring in their name, such as "impl_guile impl_sbcl impl_clisp" |
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> which could be encoded interchangeably as either |
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> |
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> # without USE_EXPAND |
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> IUSE="impl_guile impl_sbcl impl_clisp" |
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> |
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> or |
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> |
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> # with USE_EXPAND |
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> for impl in IMPL; do IUSE+="impl_${impl}"; done |
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> |
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> but the effect is that there are 3 use flags with a total of 2^3=8 |
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> combinations, while really something with exactly 3 combinations is |
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> needed: |
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> |
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> IUSE="impl" |
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> |
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> case ${impl} in |
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> guile) #use guile as backend |
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> sbcl) #use sbcl as backend |
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> clisp) #use clisp as backend |
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|
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So what you want is a USE_EXPAND version that only allows one value |
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per variable. That wouldn't be terribly difficult to do. |
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As for your idea (ignoring implementation issues), I'd expect that |
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sooner or later people will request multivalue functionality as well, |
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so we'd have the same situation there. Also in the given example, how |
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would the user/package manager actually know what values were |
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valid/available for "impl"? |
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|
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Marius |
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-- |
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