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Commit e982571c authored by sof's avatar sof
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[project @ 1999-09-11 16:50:38 by sof] 

Documented Select interface ; removed old Pretty doc
parent 064567b9
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ghc/docs/users_guide/libmisc.vsgml
+ 79
− 63
View file @ e982571c
......@@ -17,7 +17,7 @@ by giving the @-syslib misc@<nidx>-syslib misc option</nidx>.
<sect2>The @Bag@ type
<label id="Bag">
<p>
<nidx>Bag module (GHC syslib)</nidx>
<nidx>Bag module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -56,7 +56,7 @@ bagToList :: Bag elt -> [elt]
<sect2>The @FiniteMap@ type
<label id="FiniteMap">
<p>
<nidx>FiniteMap module (GHC syslib)</nidx>
<nidx>FiniteMap module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -146,7 +146,7 @@ eltsFM :: FiniteMap key elt -> [elt]
<sect2>The @ListSetOps@ type
<label id="ListSetOps">
<p>
<nidx>ListSetOps module (GHC syslib)</nidx>
<nidx>ListSetOps module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -166,7 +166,7 @@ intersectingLists :: Eq a => [a] -> [a] -> Bool
<sect2>The @Maybes@ type
<label id="Maybes">
<p>
<nidx>Maybes module (GHC syslib)</nidx>
<nidx>Maybes module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -242,7 +242,7 @@ accumulating any errors that occur.
<sect2>The @Memo@ library
<label id="memo-library">
<p>
<nidx>Memo (GHC syslib)</nidx>
<nidx>Memo (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -286,7 +286,7 @@ memo_sized :: Int -> (a -> b) -> a -> b
<sect2>The @PackedString@ type
<label id="PackedString">
<p>
<nidx>PackedString module (GHC syslib)</nidx>
<nidx>PackedString module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -347,59 +347,12 @@ substrPS :: PackedString -> Int -> Int -> PackedString
-- start and end chars you want; both 0-origin-specified
</verb></tscreen>
%************************************************************************
%* *
<sect2>The @Pretty@ type
<label id="Pretty">
<p>
<nidx>Pretty module (GHC syslib)</nidx>
%* *
%************************************************************************
This is the pretty-printer that is currently used in GHC:
<tscreen><verb>
type Pretty
ppShow :: Int{-width-} -> Pretty -> [Char]
pp'SP :: Pretty -- "comma space"
ppComma :: Pretty -- ,
ppEquals :: Pretty -- =
ppLbrack :: Pretty -- [
ppLparen :: Pretty -- (
ppNil :: Pretty -- nothing
ppRparen :: Pretty -- )
ppRbrack :: Pretty -- ]
ppSP :: Pretty -- space
ppSemi :: Pretty -- ;
ppChar :: Char -> Pretty
ppDouble :: Double -> Pretty
ppFloat :: Float -> Pretty
ppInt :: Int -> Pretty
ppInteger :: Integer -> Pretty
ppRational :: Rational -> Pretty
ppStr :: [Char] -> Pretty
ppAbove :: Pretty -> Pretty -> Pretty
ppAboves :: [Pretty] -> Pretty
ppBeside :: Pretty -> Pretty -> Pretty
ppBesides :: [Pretty] -> Pretty
ppCat :: [Pretty] -> Pretty
ppHang :: Pretty -> Int -> Pretty -> Pretty
ppInterleave :: Pretty -> [Pretty] -> Pretty -- spacing between
ppIntersperse :: Pretty -> [Pretty] -> Pretty -- no spacing between
ppNest :: Int -> Pretty -> Pretty
ppSep :: [Pretty] -> Pretty
</verb></tscreen>
%************************************************************************
%* *
<sect2>The @Set@ type
<label id="Set">
<p>
<nidx>Set module (GHC syslib)</nidx>
<nidx>Set module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -434,7 +387,7 @@ cardinality :: Set a -> Int
<sect2>The @BitSet@ interface
<label id="BitSet">
<p>
<nidx>Bitset interface (GHC syslib)</nidx>
<nidx>Bitset interface (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -464,7 +417,7 @@ listBS :: BitSet -> [Int]
<sect2>The @Util@ type
<label id="Util">
<p>
<nidx>Util module (GHC syslib)</nidx>
<nidx>Util module (misc syslib)</nidx>
%* *
%************************************************************************
......@@ -564,7 +517,7 @@ several useful C libraries, mostly from the GNU project.
<sect2>The @Readline@ interface
<label id="Readline">
<p>
<nidx>Readline library (GHC syslib)</nidx>
<nidx>Readline library (misc syslib)</nidx>
<nidx>command-line editing library</nidx>
%* *
%************************************************************************
......@@ -603,8 +556,8 @@ will see in the GNU readline documentation.)
<sect2>The @Regex@ and @MatchPS@ interfaces
<label id="Regex">
<p>
<nidx>Regex library (GHC syslib)</nidx>
<nidx>MatchPS library (GHC syslib)</nidx>
<nidx>Regex library (misc syslib)</nidx>
<nidx>MatchPS library (misc syslib)</nidx>
<nidx>regular-expressions library</nidx>
%* *
%************************************************************************
......@@ -748,7 +701,7 @@ matchPrefixPS :: PackedString -> PackedString -> Int
<sect2>The @RegexString@ interface
<label id="RegexString">
<p>
<nidx>RegexString library (GHC syslib)</nidx>
<nidx>RegexString library (misc syslib)</nidx>
<nidx>regular-expressions library</nidx>
%* *
%************************************************************************
......@@ -778,15 +731,15 @@ matchRegex
<sect2>Network-interface toolkit---@Socket@ and @SocketPrim@
<label id="Socket">
<p>
<nidx>SocketPrim interface (GHC syslib)</nidx>
<nidx>Socket interface (GHC syslib)</nidx>
<nidx>SocketPrim interface (misc syslib)</nidx>
<nidx>Socket interface (misc syslib)</nidx>
<nidx>network-interface library</nidx>
<nidx>sockets library</nidx>
<nidx>BSD sockets library</nidx>
%* *
%************************************************************************
(Darren Moffat supplied the network-interface toolkit.)
(Darren Moffat supplied the initial version of this library.)
Your best bet for documentation is to look at the code---really!---
normally in @fptools/ghc/lib/misc/{BSD,Socket,SocketPrim@.lhs}.
......@@ -852,3 +805,66 @@ mkPortNumber :: Int -> PortNumber
Various examples of networking Haskell code are provided in
%@ghc/misc/examples/@, notably the @net???/Main.hs@ programs.
%************************************************************************
%* *
<sect2>The @Select@ interface
<label id="Select">
<p>
<nidx>Select interface (misc syslib)</nidx>
%* *
%************************************************************************
The <tt/Select/ interface provides a Haskell wrapper for the <tt/select()/
OS call supplied by many modern UNIX variants. <tt/Select/ exports the
following:
<tscreen><verb>
type TimeOut = Maybe Int
-- Nothing => wait indefinitely.
-- Just x | x >= 0 => block waiting for 'x' micro seconds.
-- | otherwise => block waiting for '-x' micro seconds.
hSelect :: [Handle]
-> [Handle]
-> [Handle]
-> TimeOut
-> IO SelectResult
type SelectResult
= ( [Handle] -- input handles ready
, [Handle] -- output handles ready
, [Handle] -- exc. handles ready
)
</verb></tscreen>
Here's an example of how it could be used:
<tscreen><verb>
module Main(main) where
import Select
import IO
main :: IO ()
main = do
hSetBuffering stdin NoBuffering
putStrLn "waiting for input to appear"
hSelect [stdin] [] [] Nothing
putStrLn "input ready, let's try reading"
x <- getChar
print x
</verb></tscreen>
where the call to <tt/hSelect/ makes the process go to sleep
until there's input available on <tt/stdin/.
Notice that this particular use of <tt/hSelect/ is now really a no-op
with GHC compiled code, as its implementation of IO will take care to
avoid blocking the process (i.e., all running Haskell threads), and
call <tt/select()/ for you, if needs be. However, <tt/hSelect/ exposes
functionality that is useful in other contexts (e.g., you want to
wait for input on two <tt/Handles/ for 3 seconds, but no longer.)
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