%************************************************************************
%* *
+<sect2>The @Memo@ library
+<label id="memo-library">
+<p>
+<nidx>Memo (GHC syslib)</nidx>
+%* *
+%************************************************************************
+
+The @Memo@ library provides fast polymorphic memo functions using hash
+tables. The interface is:
+
+<tscreen><verb>
+memo :: (a -> b) -> a -> b
+</verb></tscreen>
+
+So, for example, @memo f@ is a version of @f@ that caches the results
+of previous calls.
+
+The searching is very fast, being based on pointer equality. One
+consequence of this is that the caching will only be effective if
+<em/exactly the same argument is passed again to the memoised
+function/. This means not just a copy of a previous argument, but the
+same instance. It's not useful to memoise integer functions using
+this interface, because integers are generally copied a lot and two
+instances of '27' are unlikely to refer to the same object.
+
+This memoisation library works well when the keys are large (or even
+infinite).
+
+The memo table implementation uses weak pointers and stable names (see
+the GHC/Hugs library document) to avoid space leaks and allow hashing
+for arbitrary Haskell objects. NOTE: while individual memo table
+entries will be garbage collected if the associated key becomes
+garbage, the memo table itself will not be collected if the function
+becomes garbage. We plan to fix this in a future version.
+
+There's another version of @memo@ if you want to explicitly give a
+size for the hash table (the default size is 1001 buckets):
+
+<tscreen><verb>
+memo_sized :: Int -> (a -> b) -> a -> b
+</verb></tscreen>
+
+%************************************************************************
+%* *
<sect2>The @PackedString@ type
<label id="PackedString">
<p>
%************************************************************************
You need to @import PackedString@ and heave in your
-@-syslib misc@ to use @PackedString@s.
+@-syslib ghc@ to use @PackedString@s.
The basic type and functions available are:
<tscreen><verb>
documentation (and have a @libreadline.a@ file around somewhere...)
You'll need to link any Readlining program with @-lreadline -ltermcap@,
-besides the usual @-syslib misc@ (and @-fhaskell-1.3@).
+besides the usual @-syslib ghc@ (and @-fhaskell-1.3@).
The main function you'll use is:
<tscreen><verb>
%************************************************************************
%* *
-<sect2>The @Regexp@ and @MatchPS@ interfaces
-<label id="Regexp">
+<sect2>The @Regex@ and @MatchPS@ interfaces
+<label id="Regex">
<p>
<nidx>Regex library (GHC syslib)</nidx>
<nidx>MatchPS library (GHC syslib)</nidx>
(Sigbjorn Finne supplied the regular-expressions interface.)
The @Regex@ library provides quite direct interface to the GNU
-regular-expression library, for doing manipulation on
-@PackedString@s. You probably need to see the GNU documentation
-if you are operating at this level.
+regular-expression library, for doing manipulation on @PackedString@s.
+You probably need to see the GNU documentation if you are operating at
+this level. Alternatively, you can use the simpler and higher-level
+@RegexString@ interface.
The datatypes and functions that @Regex@ provides are:
<tscreen><verb>
%************************************************************************
%* *
+<sect2>The @RegexString@ interface
+<label id="RegexString">
+<p>
+<nidx>RegexString library (GHC syslib)</nidx>
+<nidx>regular-expressions library</nidx>
+%* *
+%************************************************************************
+
+(Simon Marlow supplied the String Regex wrapper.)
+
+For simple regular expression operations, the @Regex@ library is a
+little heavyweight. @RegexString@ permits regex matching on ordinary
+Haskell @String@s.
+
+The datatypes and functions that @RegexString@ provides are:
+<tscreen><verb>
+data Regex -- a compiled regular expression
+
+mkRegEx
+ :: String -- regexp to compile
+ -> Regex -- compiled regexp
+
+matchRegex
+ :: Regex -- compiled regexp
+ -> String -- string to match
+ -> Maybe [String] -- text of $1, $2, ... (if matched)
+</verb></tscreen>
+
+%************************************************************************
+%* *
<sect2>Network-interface toolkit---@Socket@ and @SocketPrim@
<label id="Socket">
<p>
socketPort :: Socket -> IO PortID
data PortID -- PortID is a non-abstract type
- = Service String -- Service Name eg "ftp"
- | PortNumber Int -- User defined Port Number
- | UnixSocket String -- Unix family socket in file system
+ = Service String -- Service Name eg "ftp"
+ | PortNumber PortNumber -- User defined Port Number
+ | UnixSocket String -- Unix family socket in file system
type Hostname = String
+
+ -- 16-bit value (stored in network byte order).
+data PortNumber
+ -- instance of: Eq, Num, Show.
+
+mkPortNumber :: Int -> PortNumber
</verb></tscreen>
Various examples of networking Haskell code are provided in
projects / ghc-hetmet.git / blobdiff