bringert:
> > noop :: IO () -- generalise to other Monads?
> >
> >This would actually not be too hard to write, given my existing work,
> >and then of course the executable would simply be a thin wrapper.
>
> As suggested above, this patch moves the core functionality to a
> library module, Control.Nop. Furthermore, the nop function is
> generalized to a polyvariadic function, so that you can now write for
> example:
Ah, great. Now we can write a fast nop using ByteStrings for speed.
import Data.ByteString.Char8
import Control.Nop
-- | main, do nothing quickly
main :: IO ()
main = nop (pack "do nothing")
Demo patch for fast-hnop attached.
-- Don
New patches:
[Moved the definition of the nop function to a library module, Control.Nop.
Reimplemented Main.hs using Control.Nop. Generalized the nop function to a
polyvariadic function.
[EMAIL PROTECTED] {
adddir ./Control
addfile ./Control/Nop.hs
hunk ./Control/Nop.hs 1
+-----------------------------------------------------------------------------
+-- |
+-- Module : Control.Nop
+-- Copyright : Copyright 2006, Bjorn Bringert ([EMAIL PROTECTED])
+-- License : BSD3
+--
+-- Maintainer : Bjorn Bringert <[EMAIL PROTECTED]>
+-- Stability : experimental
+-- Portability : portable
+--
+-- This is a generalization of Ashley Yakeley's original HNOP
+-- program to a polyvariadic function, which still does nothing.
+-- The result is either an IO action which does nothing,
+-- or pure nothingness.
+--
+-----------------------------------------------------------------------------
+module Control.Nop where
+
+-- | The class of functions which do nothing.
+class Nop a where
+ -- | Do nothing.
+ -- The most useful familiy of 'nop' functions is probably:
+ -- @nop :: a1 -> ... -> an -> IO ()@
+ nop :: a
+
+instance Nop () where
+ nop = ()
+
+instance Nop a => Nop (IO a) where
+ nop = return nop
+
+instance Nop b => Nop (a -> b) where
+ nop _ = nop
+
hunk ./Main.hs 4
+import Control.Nop
+
hunk ./Main.hs 8
-main = return ()
+main = nop
hunk ./hnop.cabal 6
+Exposed-modules: Control.Nop
}
[Add demo fast-hnop, using Data.ByteString for speed
Don Stewart <[EMAIL PROTECTED]>**20060701083508] {
addfile ./Fast.hs
hunk ./Fast.hs 1
+module Main where
+
+import Data.ByteString.Char8
+import Control.Nop
+
+-- | main, do nothing quickly
+main :: IO ()
+main = nop (pack "do nothing")
hunk ./hnop.cabal 5
-build-depends: base
+build-depends: base, fps
hunk ./hnop.cabal 11
+Executable: fast-hnop
+Main-Is: Fast.hs
+
}
Context:
[remove unnecessary Makefile
Ashley Yakeley <[EMAIL PROTECTED]>**20060630191533]
[use correct GHC options pragma
Ashley Yakeley <[EMAIL PROTECTED]>**20060630191505]
[fix up cabal file
Ashley Yakeley <[EMAIL PROTECTED]>**20060630075323]
[haddock-ise hnop
[EMAIL PROTECTED]
[cabalise hnop
[EMAIL PROTECTED]
[initial version
Ashley Yakeley <[EMAIL PROTECTED]>**20060630034031]
Patch bundle hash:
8ba09d4b5f29d8136032effcf004a4a47cf274c1
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