Dear library folks, Having finished my current batch of compiler hacking I'd like to kickstart the libraries discussion again. As you may recall, we were stuck on the layout of the library hierarchy - below I've appended a new version (relative to Malcolm's last version) with some changes which I've listed first. I hope we can take this and converge on something which we're all happy with. I've also included an attempt at a set of guidelines for the contents of the top-level categories, as requested by one or two people: this should make it easier to place new libraries, and it's also useful to see some of the places where categories overlap. We should also write down guidelines on naming (not only for libraries themselves but also for functions, types and classes) at some point. There are several process-related issues to agree on before we can start actually writing code, but this message is too long already so I'll try to tackle them in separate mails tomorrow. Cheers, Simon Changes to the hierarchy - Data and Structures merged. The distinction between the two isn't clear: eg. IORef and STRef could be considered structures, as could Complex, Maybe, Either, List, PackedString etc. Put them all under Data - I think Data.Array, Data,Trees etc. look quite natural. - Moved Control back up to the top level (was previously in System). I'll give way on the Lang issue, but I think we'll have to expand the remit of Data to include not only data types themselves but also operations and classes over data (we already have Data.Memo), so now Dynamic and Generics fit in there too. Having a 'Type' hierarchy doesn't seem appropriate, because most libraries in Data also define types and it would just create confusion. - Moved Monad back into Control. - Added hypothetical Network.Protocol.{HTTP,FTP,SMTP,...} - Added Data.Bool, Data.Tuple - Added Text.Show & Text.Read - Moved Prelude.ShowFunctions to Text.Show.Functions. - Clarified that Numeric exports the Haskell 98 numeric classes (Num, Integral, Real etc.). - Renamed URL back to URI. - Capitalised NHC (hope that's OK). - Algebra & Numeric could be merged (as suggested by Dylan Thurston in the previous thread), I haven't made any changes here yet though. Numeric seems an appropriate place for the existing numeric operations and classes, but 'Math' would be less so. - There are still a few things left in the Prelude that don't have a home elsewhere: curry, uncurry, id, const, (.), asTypeOf, seq, ($!). ------------------------------------------------------------------------ ----- Hierarchy guidelines Control Libraries which provide functions, types or classes whose purpose is primarily to express control structure. Data Libraries which provide data types, operations over data types, or type classes, except for libraries for which one of the other more specific categories is appropriate. Algebra ? (someone more knowledgable please fill this in) Database Libraries for providing access to or operations for building databases. Debug Support for debugging Haskell programs. FileFormat Support for reading and/or writing various file formats (except language source which lives in Language, and textual file formats which are catered for in Text). Foreign Interaction with code written in a foreign programming language. Graphics Libraries for producing graphics or providing graphical user interfaces. Language Libraries for operating on or generating source code in various programming languages, including parsers, pretty printers, abstract syntax definitions etc. Numeric Functions and classes which provide operations over numeric data. Network Libraries for communicating over a network, including implementations of network protocols and standards. System Libraries for communication with the system on which the Haskell program is running (including the runtime system). Text Libraries for parsing and generating data in a textual format (including structured textual formats such as XML, HTML, but not including programming language source, which lives in Language). Others: GHC, NHC, Edison Further top-level names will be allocated on an as-needed basis. ------------------------------------------------------------------------ ----- Prelude -- Haskell98 Prelude (mostly just re-exports other parts of the tree). Control Exception -- (opt, inc. error & undefined) Concurrent -- as hslibs/concurrent CVar -- these could all be moved under Data Chan MVar Merge QSem QSemN SampleVar Semaphore Parallel -- as hslibs/concurrent/Parallel Strategies Monad -- Haskell 98 Monad library ST -- ST defaults to Strict variant? Strict -- renaming for ST Lazy -- renaming for LazyST Either -- monad libraries State Error etc. Data Bits Bool -- &&, ||, not, otherwise Tuple -- fst, snd Char -- H98 Complex -- H98 Dynamic Either Int Maybe -- H98 List -- H98 PackedString Ratio -- H98 Word IORef STRef Binary -- Haskell binary I/O Digest MD5 ... -- others (CRC ?) Array -- Haskell 98 Array library Overloaded -- (opt) IArray - GHC's overloaded arr libs Mutable -- (opt) MArray IO -- mutable arrays in the IO/ST monads ST Trees AVL RedBlack BTree Queue Bankers FIFO Collection Graphs FiniteMap Set Memo -- (opt) Unique Algebra DomainConstructor -- formerly DoCon Geometric -- formerly BasGeomAlg Database MySQL PostgreSQL ODBC Debug Trace Quickcheck Observe -- choose a default amongst the variants Textual -- Andy Gill's release 1 ToXmlFile -- Andy Gill's XML browser variant GHood -- Claus Reinke's animated variant Edison -- (opt, uses multi-param type classes) Prelude -- large self-contained packages should have Collection -- their own hierarchy? Like a vendor branch. Queue -- Or should the whole Edison tree be placed ... -- under [Data.]Structures? FileFormat -- 'Codec' might be a more accurate name? Compression Gzip Bzip2 Graphics Jpeg Ppm Png Audio Wav Mp3 Video Mpeg QuickTime Avi Foreign Ptr StablePtr ForeignPtr -- rename to FinalisedPtr? to void confusion with Foreign.Ptr Storable Marshal Alloc Array Errors Utils C Types Errors Strings Graphics UI Gtk FranTk Fudgets CleanIO Drawing HOpenGL Format -- use FileFormat.Graphics instead Language Haskell -- hslibs/hssource Syntax Abstract Core Lexer Parser Pretty Python? C? Numeric -- exports std. H98 numeric type classes DSP FastFourierTransform Noise Oscillator Network -- won't need to be optional (will use FFI only) Socket -- redesign (merged Socket, SocketPrim, BSD) URI -- general URI parsing CGI -- one in hslibs is ok? Protocol HTTP FTP SMTP System -- Interaction with the "system" IO -- H98 + IOExts - IOArray - IORef Directory Select Console GetOpt Readline Posix -- redesigned, use FFI only IO -- there was a suggestion to split Posix into Process -- separate chunks like IO + Process Win32 -- the full win32 operating system API Mem -- rename from cryptic 'GC' WeakPointer -- (opt) StableName -- (opt) Time -- H98 + extensions Locale -- H98 CPUTime -- H98 -- split H98 "System" (too generic) into: Exit Environment (getArgs, getProgName, getEnv ...) Text Read Show Functions -- optional instance of Show for functions. Regex -- previously RegexString PrettyPrinter -- default (HughesPJ?) HughesPJ Wadler ... Html -- HTML combinator lib Xml Combinators Parse Pretty Types ParserCombinators -- no default Parsec Hutton_Meijer ... GHC Primitives UnboxedTypes ... NHC Stuff