Question

我需要安装protobuf 2.6.1

brew install protobuf给了我3.1.0，当前版本

如何在Mac上安装protobuf 2.6.1？

感谢。

Answer 1

有人维护家庭酿造的版本配方，您可以使用：

import Data.Char
import Data.Maybe
import Data.Word

instance ( Enum k, Bounded k ) => Foldable ((->) k) where
    foldMap h f = foldMap (h . f) domain

instance ( Enum k, Bounded k, Eq k ) => Traversable ((->) k) where
    traverse h f = fmap (\vs k -> fromJust $ k `lookup` zip domain vs) (traverse (h . f) domain)

domain :: ( Enum k, Bounded k ) => [k]
domain = enumFromTo minBound maxBound

tabulate :: ( Enum k, Bounded k ) => (k -> a) -> [(k, a)]
tabulate f = zip domain (map f domain)

f1 :: Bool -> Int
f1 b = if b then 42 else 666

f2 :: Ordering -> Char
f2 LT = 'l'
f2 EQ = 'e'
f2 GT = 'g'

f3 :: Word8 -> Bool
f3 n = fromIntegral n < 256

f4 :: Word16 -> Bool
f4 n = fromIntegral n < 256

main = do
    print (tabulate f1)
    print (tabulate <$> traverse (\n -> [n, 2*n]) f1)
    putStrLn ""
    print (tabulate f2)
    print (tabulate <$> traverse (\c -> [c, toUpper c]) f2)
    putStrLn ""
    print (tabulate f3)
    print (tabulate <$> traverse (\b -> if b then Just b else Nothing) f3)
    putStrLn ""
    print (tabulate <$> traverse (\b -> if b then Just b else Nothing) f4)

如何安装旧版本的protobuf？

1 个答案: