%
-% (c) The GRASP/AQUA Project, Glasgow University, 1993-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
%
\section[GHC_Main]{Main driver for Glasgow Haskell compiler}
\begin{code}
-#include "HsVersions.h"
-
module Main ( main ) where
-IMP_Ubiq(){-uitous-}
-IMPORT_1_3(IO(hGetContents,stdin,stderr,hPutStr,hClose,openFile,IOMode(..)))
+#include "HsVersions.h"
+import IO ( hPutStr, stderr )
import HsSyn
-import RdrHsSyn ( RdrName )
import BasicTypes ( NewOrData(..) )
-import ReadPrefix ( rdModule )
+import RdrHsSyn ( RdrNameHsModule )
+import FastString ( mkFastCharString, unpackFS )
+import StringBuffer ( hGetStringBuffer )
+import Parser ( parse )
+import Lex ( PState(..), P, ParseResult(..) )
+import SrcLoc ( mkSrcLoc )
+
import Rename ( renameModule )
-import RnMonad ( ExportEnv )
-import MkIface -- several functions
-import TcModule ( typecheckModule )
-import Desugar ( deSugar, pprDsWarnings
-#if __GLASGOW_HASKELL__ <= 200
- , DsMatchContext, DsWarnFlavour
-#endif
- )
+import MkIface ( startIface, ifaceDecls, endIface )
+import TcModule ( TcResults(..), typecheckModule )
+import Desugar ( deSugar )
import SimplCore ( core2core )
+import CoreLint ( endPass )
+import CoreTidy ( tidyCorePgm )
import CoreToStg ( topCoreBindsToStg )
-import StgSyn ( collectFinalStgBinders )
+import StgSyn ( collectFinalStgBinders, pprStgBindings )
import SimplStg ( stg2stg )
import CodeGen ( codeGen )
-#if ! OMIT_NATIVE_CODEGEN
-import AsmCodeGen ( dumpRealAsm, writeRealAsm )
-#endif
+import CodeOutput ( codeOutput )
-import AbsCSyn ( absCNop, AbstractC )
-import AbsCUtils ( flattenAbsC )
-import CoreUnfold ( Unfolding )
-import Bag ( emptyBag, isEmptyBag )
+import Module ( ModuleName, moduleNameUserString )
+import AbsCSyn ( absCNop )
import CmdLineOpts
-import ErrUtils ( pprBagOfErrors, ghcExit )
+import ErrUtils ( ghcExit, doIfSet, dumpIfSet )
import Maybes ( maybeToBool, MaybeErr(..) )
-import Specialise ( SpecialiseData(..) )
-import StgSyn ( pprPlainStgBinding, GenStgBinding )
-import TcInstUtil ( InstInfo )
import TyCon ( isDataTyCon )
+import Class ( classTyCon )
import UniqSupply ( mkSplitUniqSupply )
-import PprAbsC ( dumpRealC, writeRealC )
-import PprCore ( pprCoreBinding )
-import Outputable ( PprStyle(..), Outputable(..) )
-import Pretty
+import FiniteMap ( emptyFM )
+import Outputable
+import Char ( isSpace )
+#if REPORT_TO_MOTHERLODE && __GLASGOW_HASKELL__ >= 303
+import SocketPrim
+import BSD
+import IOExts ( unsafePerformIO )
+import NativeInfo ( os, arch )
+#endif
-import Id ( GenId ) -- instances
-import Name ( Name ) -- instances
-import PprType ( GenType, GenTyVar ) -- instances
-import TyVar ( GenTyVar ) -- instances
-import Unique ( Unique ) -- instances
\end{code}
\begin{code}
main =
- _scc_ "main"
- hGetContents stdin >>= \ input_pgm ->
- let
- cmd_line_info = classifyOpts
- in
- doIt cmd_line_info input_pgm
+ -- _scc_ "main"
+ doIt classifyOpts
\end{code}
\begin{code}
-doIt :: ([CoreToDo], [StgToDo]) -> String -> IO ()
+parseModule :: IO (ModuleName, RdrNameHsModule)
+parseModule = do
+ buf <- hGetStringBuffer True{-expand tabs-} (unpackFS src_filename)
+ case parse buf PState{ bol = 0#, atbol = 1#,
+ context = [], glasgow_exts = glaexts,
+ loc = mkSrcLoc src_filename 1 } of
+
+ PFailed err -> do
+ printErrs err
+ ghcExit 1
+ return (error "parseModule") -- just to get the types right
+
+ POk _ m@(HsModule mod _ _ _ _ _) ->
+ return (mod, m)
+ where
+ glaexts | opt_GlasgowExts = 1#
+ | otherwise = 0#
+\end{code}
+
+\begin{code}
+doIt :: ([CoreToDo], [StgToDo]) -> IO ()
-doIt (core_cmds, stg_cmds) input_pgm
- = doDump opt_Verbose "Glasgow Haskell Compiler, version 2.03, for Haskell 1.4" "" >>
+doIt (core_cmds, stg_cmds)
+ = doIfSet opt_Verbose
+ (hPutStr stderr "Glasgow Haskell Compiler, version " >>
+ hPutStr stderr compiler_version >>
+ hPutStr stderr ", for Haskell 98\n" >>
+ hPutStr stderr "\tcompiled by GHC version " >>
+ hPutStr stderr booter_version >>
+ hPutStr stderr "\n") >>
- -- ******* READER
- show_pass "Reader" >>
- _scc_ "Reader"
- rdModule >>= \ (mod_name, rdr_module) ->
+ -------------------------- Reader ----------------
+ show_pass "Parser" >>
+ _scc_ "Parser"
+ parseModule >>= \ (mod_name, rdr_module) ->
- doDump opt_D_dump_rdr "Reader:"
- (pp_show (ppr pprStyle rdr_module)) >>
+ dumpIfSet opt_D_dump_parsed "Parser" (ppr rdr_module) >>
- doDump opt_D_source_stats "\nSource Statistics:"
- (pp_show (ppSourceStats rdr_module)) >>
+ dumpIfSet opt_D_source_stats "Source Statistics"
+ (ppSourceStats False rdr_module) >>
-- UniqueSupplies for later use (these are the only lower case uniques)
--- _scc_ "spl-rn"
mkSplitUniqSupply 'r' >>= \ rn_uniqs -> -- renamer
--- _scc_ "spl-tc"
mkSplitUniqSupply 'a' >>= \ tc_uniqs -> -- typechecker
--- _scc_ "spl-ds"
mkSplitUniqSupply 'd' >>= \ ds_uniqs -> -- desugarer
--- _scc_ "spl-sm"
- mkSplitUniqSupply 's' >>= \ sm_uniqs -> -- core-to-core simplifier
--- _scc_ "spl-c2s"
+ mkSplitUniqSupply 'r' >>= \ ru_uniqs -> -- rules
mkSplitUniqSupply 'c' >>= \ c2s_uniqs -> -- core-to-stg
--- _scc_ "spl-st"
+ mkSplitUniqSupply 'u' >>= \ tidy_uniqs -> -- tidy up
mkSplitUniqSupply 'g' >>= \ st_uniqs -> -- stg-to-stg passes
--- _scc_ "spl-absc"
- mkSplitUniqSupply 'f' >>= \ fl_uniqs -> -- absC flattener
--- _scc_ "spl-ncg"
mkSplitUniqSupply 'n' >>= \ ncg_uniqs -> -- native-code generator
- -- ******* RENAMER
+ -------------------------- Rename ----------------
show_pass "Renamer" >>
_scc_ "Renamer"
- renameModule rn_uniqs rdr_module >>=
- \ (maybe_rn_stuff, rn_errs_bag, rn_warns_bag) ->
-
- checkErrors rn_errs_bag rn_warns_bag >>
+ renameModule rn_uniqs rdr_module >>= \ maybe_rn_stuff ->
case maybe_rn_stuff of {
Nothing -> -- Hurrah! Renamer reckons that there's no need to
-- go any further
- hPutStr stderr "No recompilation required!\n" >>
- ghcExit 0 ;
-
- -- Oh well, we've got to recompile for real
- Just (rn_mod, iface_file_stuff, rn_name_supply, imported_modules) ->
+ reportCompile mod_name "Compilation NOT required!" >>
+ return ();
+
+ Just (this_mod, rn_mod, iface_file_stuff, rn_name_supply, imported_modules) ->
+ -- Oh well, we've got to recompile for real
-
- doDump opt_D_dump_rn "Renamer:"
- (pp_show (ppr pprStyle rn_mod)) >>
-
+ -------------------------- Start interface file ----------------
-- Safely past renaming: we can start the interface file:
-- (the iface file is produced incrementally, as we have
-- the information that we need...; we use "iface<blah>")
-- "endIface" finishes the job.
- startIface mod_name >>= \ if_handle ->
- ifaceMain if_handle iface_file_stuff >>
+ startIface this_mod iface_file_stuff >>= \ if_handle ->
- -- ******* TYPECHECKER
- show_pass "TypeCheck" >>
+ -------------------------- Typechecking ----------------
+ show_pass "TypeCheck" >>
_scc_ "TypeCheck"
- case (case (typecheckModule tc_uniqs {-idinfo_fm-} rn_name_supply rn_mod) of
- Succeeded (stuff, warns)
- -> (emptyBag, warns, stuff)
- Failed (errs, warns)
- -> (errs, warns, error "tc_results"))
-
- of { (tc_errs_bag, tc_warns_bag, tc_results) ->
-
- checkErrors tc_errs_bag tc_warns_bag >>
-
- case tc_results
- of { (typechecked_quint@(recsel_binds, class_binds, inst_binds, val_binds, const_binds),
- local_tycons, local_classes, inst_info, pragma_tycon_specs,
- ddump_deriv) ->
-
- doDump opt_D_dump_tc "Typechecked:"
- (pp_show (vcat [
- ppr pprStyle recsel_binds,
- ppr pprStyle class_binds,
- ppr pprStyle inst_binds,
- ppr pprStyle const_binds,
- ppr pprStyle val_binds])) >>
-
- doDump opt_D_dump_deriv "Derived instances:"
- (pp_show (ddump_deriv pprStyle)) >>
-
- -- ******* DESUGARER
- show_pass "DeSugar" >>
+ typecheckModule tc_uniqs rn_name_supply
+ iface_file_stuff rn_mod >>= \ maybe_tc_stuff ->
+ case maybe_tc_stuff of {
+ Nothing -> ghcExit 1; -- Type checker failed
+
+ Just (tc_results@(TcResults {tc_tycons = local_tycons,
+ tc_classes = local_classes,
+ tc_insts = inst_info })) ->
+
+
+ -------------------------- Desugaring ----------------
_scc_ "DeSugar"
- let
- (desugared,ds_warnings)
- = deSugar ds_uniqs mod_name typechecked_quint
- in
- (if isEmptyBag ds_warnings then
- return ()
- else
- hPutStr stderr (pp_show (pprDsWarnings pprErrorsStyle ds_warnings))
- >> hPutStr stderr "\n"
- ) >>
-
- doDump opt_D_dump_ds "Desugared:" (pp_show (vcat
- (map (pprCoreBinding pprStyle) desugared)))
- >>
-
- -- ******* CORE-TO-CORE SIMPLIFICATION (NB: I/O op)
- show_pass "Core2Core" >>
+ deSugar this_mod ds_uniqs tc_results >>= \ (desugared, rules, h_code, c_code) ->
+
+
+ -------------------------- Main Core-language transformations ----------------
_scc_ "Core2Core"
- let
- local_data_tycons = filter isDataTyCon local_tycons
- in
- core2core core_cmds mod_name pprStyle
- sm_uniqs local_data_tycons pragma_tycon_specs desugared
- >>=
+ core2core core_cmds desugared rules >>= \ (simplified, imp_rule_ids) ->
- \ (simplified,
- SpecData _ _ _ gen_data_tycons all_tycon_specs _ _ _) ->
+ -- Do the final tidy-up
+ tidyCorePgm tidy_uniqs this_mod
+ simplified imp_rule_ids >>= \ (tidy_binds, tidy_imp_rule_ids) ->
- doDump opt_D_dump_simpl "Simplified:" (pp_show (vcat
- (map (pprCoreBinding pprStyle) simplified)))
- >>
- -- ******* STG-TO-STG SIMPLIFICATION
+ -------------------------- Convert to STG code -------------------------------
show_pass "Core2Stg" >>
_scc_ "Core2Stg"
let
- stg_binds = topCoreBindsToStg c2s_uniqs simplified
+ stg_binds = topCoreBindsToStg c2s_uniqs tidy_binds
in
+ -------------------------- Simplify STG code -------------------------------
show_pass "Stg2Stg" >>
_scc_ "Stg2Stg"
- stg2stg stg_cmds mod_name pprStyle st_uniqs stg_binds
- >>=
-
- \ (stg_binds2, cost_centre_info) ->
+ stg2stg stg_cmds this_mod st_uniqs stg_binds >>= \ (stg_binds2, cost_centre_info) ->
- doDump opt_D_dump_stg "STG syntax:"
- (pp_show (vcat (map (pprPlainStgBinding pprStyle) stg_binds2)))
- >>
+ -------------------------- Interface file -------------------------------
-- Dump instance decls and type signatures into the interface file
+ _scc_ "Interface"
let
- final_ids = collectFinalStgBinders stg_binds2
+ final_ids = collectFinalStgBinders (map fst stg_binds2)
in
- _scc_ "Interface"
- ifaceDecls if_handle local_tycons local_classes inst_info final_ids simplified >>
+ ifaceDecls if_handle local_tycons local_classes
+ inst_info final_ids tidy_binds imp_rule_ids >>
endIface if_handle >>
- -- We are definitely done w/ interface-file stuff at this point:
- -- (See comments near call to "startIface".)
-
+ -- We are definitely done w/ interface-file stuff at this point:
+ -- (See comments near call to "startIface".)
- -- ******* "ABSTRACT", THEN "FLAT", THEN *REAL* C!
+
+ -------------------------- Code generation -------------------------------
show_pass "CodeGen" >>
_scc_ "CodeGen"
- let
- abstractC = codeGen mod_name -- module name for CC labelling
- cost_centre_info
- imported_modules -- import names for CC registering
- gen_data_tycons -- type constructors generated locally
- all_tycon_specs -- tycon specialisations
- stg_binds2
-
- flat_abstractC = flattenAbsC fl_uniqs abstractC
- in
- doDump opt_D_dump_absC "Abstract C:"
- (dumpRealC abstractC) >>
+ codeGen this_mod imported_modules
+ cost_centre_info
+ local_tycons local_classes
+ stg_binds2 >>= \ abstractC ->
- doDump opt_D_dump_flatC "Flat Abstract C:"
- (dumpRealC flat_abstractC) >>
+ -------------------------- Code output -------------------------------
+ show_pass "CodeOutput" >>
_scc_ "CodeOutput"
- -- You can have C (c_output) or assembly-language (ncg_output),
- -- but not both. [Allowing for both gives a space leak on
- -- flat_abstractC. WDP 94/10]
- let
- (flat_absC_c, flat_absC_ncg) =
- case (maybeToBool opt_ProduceC || opt_D_dump_realC,
- maybeToBool opt_ProduceS || opt_D_dump_asm) of
- (True, False) -> (flat_abstractC, absCNop)
- (False, True) -> (absCNop, flat_abstractC)
- (False, False) -> (absCNop, absCNop)
- (True, True) -> error "ERROR: Can't do both .hc and .s at the same time"
-
- c_output_d = dumpRealC flat_absC_c
- c_output_w = (\ f -> writeRealC f flat_absC_c)
-
-#if OMIT_NATIVE_CODEGEN
- ncg_output_d = error "*** GHC not built with a native-code generator ***"
- ncg_output_w = ncg_output_d
-#else
- ncg_output_d = dumpRealAsm flat_absC_ncg ncg_uniqs
- ncg_output_w = (\ f -> writeRealAsm f flat_absC_ncg ncg_uniqs)
-#endif
- in
+ codeOutput this_mod c_code h_code abstractC ncg_uniqs >>
- doDump opt_D_dump_asm "" ncg_output_d >>
- doOutput opt_ProduceS ncg_output_w >>
- doDump opt_D_dump_realC "" c_output_d >>
- doOutput opt_ProduceC c_output_w >>
+ -------------------------- Final report -------------------------------
+ reportCompile mod_name (showSDoc (ppSourceStats True rdr_module)) >>
ghcExit 0
- } } }
+ } }
where
-------------------------------------------------------------
- -- ****** printing styles and column width:
-
-
- -------------------------------------------------------------
-- ****** help functions:
show_pass
then \ what -> hPutStr stderr ("*** "++what++":\n")
else \ what -> return ()
- doOutput switch io_action
- = case switch of
- Nothing -> return ()
- Just fname ->
- openFile fname WriteMode >>= \ handle ->
- io_action handle >>
- hClose handle
-
- doDump switch hdr string
- = if switch
- then hPutStr stderr ("\n\n" ++ (take 80 $ repeat '=')) >>
- hPutStr stderr ('\n': hdr) >>
- hPutStr stderr ('\n': string) >>
- hPutStr stderr "\n"
- else return ()
-
-
-pprCols = (80 :: Int) -- could make configurable
-
-(pprStyle, pprErrorsStyle)
- | opt_PprStyle_All = (PprShowAll, PprShowAll)
- | opt_PprStyle_Debug = (PprDebug, PprDebug)
- | opt_PprStyle_User = (PprQuote, PprQuote)
- | otherwise = (PprDebug, PprQuote)
-
-pp_show p = show p -- ToDo: use pprCols
-
-checkErrors errs_bag warns_bag
- | not (isEmptyBag errs_bag)
- = hPutStr stderr (pp_show (pprBagOfErrors pprErrorsStyle errs_bag))
- >> hPutStr stderr "\n" >>
- hPutStr stderr (pp_show (pprBagOfErrors pprErrorsStyle warns_bag))
- >> hPutStr stderr "\n" >>
- ghcExit 1
-
- | not (isEmptyBag warns_bag)
- = hPutStr stderr (pp_show (pprBagOfErrors pprErrorsStyle warns_bag)) >>
- hPutStr stderr "\n"
-
- | otherwise = return ()
-
-
-ppSourceStats (HsModule name version exports imports fixities decls src_loc)
- = vcat (map pp_val
+ppSourceStats short (HsModule name version exports imports decls src_loc)
+ = (if short then hcat else vcat)
+ (map pp_val
[("ExportAll ", export_all), -- 1 if no export list
("ExportDecls ", export_ds),
("ExportModules ", export_ms),
])
where
pp_val (str, 0) = empty
- pp_val (str, n) = hcat [text str, int n]
-
- fixity_ds = length fixities
- type_decls = [d | TyD d@(TySynonym _ _ _ _) <- decls]
- data_decls = [d | TyD d@(TyData DataType _ _ _ _ _ _ _) <- decls]
- newt_decls = [d | TyD d@(TyData NewType _ _ _ _ _ _ _) <- decls]
- type_ds = length type_decls
- data_ds = length data_decls
- newt_ds = length newt_decls
- class_decls = [d | ClD d <- decls]
- class_ds = length class_decls
+ pp_val (str, n)
+ | not short = hcat [text str, int n]
+ | otherwise = hcat [text (trim str), equals, int n, semi]
+
+ trim ls = takeWhile (not.isSpace) (dropWhile isSpace ls)
+
+ fixity_ds = length [() | FixD d <- decls]
+ -- NB: this omits fixity decls on local bindings and
+ -- in class decls. ToDo
+
+ tycl_decls = [d | TyClD d <- decls]
+ (class_ds, data_ds, newt_ds, type_ds) = countTyClDecls tycl_decls
+
inst_decls = [d | InstD d <- decls]
inst_ds = length inst_decls
default_ds = length [() | DefD _ <- decls]
(import_no, import_qual, import_as, import_all, import_partial, import_hiding)
= foldr add6 (0,0,0,0,0,0) (map import_info imports)
(data_constrs, data_derivs)
- = foldr add2 (0,0) (map data_info (newt_decls ++ data_decls))
+ = foldr add2 (0,0) (map data_info tycl_decls)
(class_method_ds, default_method_ds)
- = foldr add2 (0,0) (map class_info class_decls)
+ = foldr add2 (0,0) (map class_info tycl_decls)
(inst_method_ds, method_specs, method_inlines)
= foldr add3 (0,0,0) (map inst_info inst_decls)
count_binds (MonoBind b sigs _) = case (count_monobinds b, count_sigs sigs) of
((vs,fs),(ts,_,ss,is)) -> (vs,fs,ts,ss,is)
- count_monobinds EmptyMonoBinds = (0,0)
- count_monobinds (AndMonoBinds b1 b2) = count_monobinds b1 `add2` count_monobinds b2
+ count_monobinds EmptyMonoBinds = (0,0)
+ count_monobinds (AndMonoBinds b1 b2) = count_monobinds b1 `add2` count_monobinds b2
count_monobinds (PatMonoBind (VarPatIn n) r _) = (1,0)
- count_monobinds (PatMonoBind p r _) = (0,1)
- count_monobinds (FunMonoBind f _ m _) = (0,1)
+ count_monobinds (PatMonoBind p r _) = (0,1)
+ count_monobinds (FunMonoBind f _ m _) = (0,1)
count_sigs sigs = foldr add4 (0,0,0,0) (map sig_info sigs)
sig_info (Sig _ _ _) = (1,0,0,0)
sig_info (ClassOpSig _ _ _ _) = (0,1,0,0)
- sig_info (SpecSig _ _ _ _) = (0,0,1,0)
+ sig_info (SpecSig _ _ _) = (0,0,1,0)
sig_info (InlineSig _ _) = (0,0,0,1)
sig_info _ = (0,0,0,0)
- import_info (ImportDecl _ qual _ as spec _)
+ import_info (ImportDecl _ _ qual as spec _)
= add6 (1, qual_info qual, as_info as, 0,0,0) (spec_info spec)
qual_info False = 0
qual_info True = 1
data_info (TyData _ _ _ _ constrs derivs _ _)
= (length constrs, case derivs of {Nothing -> 0; Just ds -> length ds})
+ data_info other = (0,0)
- class_info (ClassDecl _ _ _ meth_sigs def_meths _ _)
+ class_info (ClassDecl _ _ _ meth_sigs def_meths _ _ _ _ _)
= case count_sigs meth_sigs of
(_,classops,_,_) ->
(classops, addpr (count_monobinds def_meths))
+ class_info other = (0,0)
inst_info (InstDecl _ inst_meths inst_sigs _ _)
= case count_sigs inst_sigs of
(_,_,ss,is) ->
(addpr (count_monobinds inst_meths), ss, is)
+ addpr :: (Int,Int) -> Int
+ add1 :: Int -> Int -> Int
+ add2 :: (Int,Int) -> (Int,Int) -> (Int, Int)
+ add3 :: (Int,Int,Int) -> (Int,Int,Int) -> (Int, Int, Int)
+ add4 :: (Int,Int,Int,Int) -> (Int,Int,Int,Int) -> (Int, Int, Int, Int)
+ add5 :: (Int,Int,Int,Int,Int) -> (Int,Int,Int,Int,Int) -> (Int, Int, Int, Int, Int)
+ add6 :: (Int,Int,Int,Int,Int,Int) -> (Int,Int,Int,Int,Int,Int) -> (Int, Int, Int, Int, Int, Int)
+
addpr (x,y) = x+y
add1 x1 y1 = x1+y1
add2 (x1,x2) (y1,y2) = (x1+y1,x2+y2)
add5 (x1,x2,x3,x4,x5) (y1,y2,y3,y4,y5) = (x1+y1,x2+y2,x3+y3,x4+y4,x5+y5)
add6 (x1,x2,x3,x4,x5,x6) (y1,y2,y3,y4,y5,y6) = (x1+y1,x2+y2,x3+y3,x4+y4,x5+y5,x6+y6)
\end{code}
+
+\begin{code}
+compiler_version :: String
+compiler_version =
+ case (show opt_HiVersion) of
+ [x] -> ['0','.',x]
+ ls@[x,y] -> "0." ++ ls
+ ls -> go ls
+ where
+ -- 10232353 => 10232.53
+ go ls@[x,y] = '.':ls
+ go (x:xs) = x:go xs
+
+booter_version
+ = case "\
+ \ __GLASGOW_HASKELL__" of
+ ' ':n:ns -> n:'.':ns
+ ' ':m -> m
+\end{code}
+
+\begin{code}
+reportCompile :: ModuleName -> String -> IO ()
+#if REPORT_TO_MOTHERLODE && __GLASGOW_HASKELL__ >= 303
+reportCompile mod_name info
+ | not opt_ReportCompile = return ()
+ | otherwise = (do
+ sock <- udpSocket 0
+ addr <- motherShip
+ sendTo sock (moduleNameUserString mod_name ++ ';': compiler_version ++
+ ';': os ++ ';':arch ++ '\n':' ':info ++ "\n") addr
+ return ()) `catch` (\ _ -> return ())
+
+motherShip :: IO SockAddr
+motherShip = do
+ he <- getHostByName "laysan.dcs.gla.ac.uk"
+ case (hostAddresses he) of
+ [] -> IOERROR (userError "No address!")
+ (x:_) -> return (SockAddrInet motherShipPort x)
+
+--magick
+motherShipPort :: PortNumber
+motherShipPort = mkPortNumber 12345
+
+-- creates a socket capable of sending datagrams,
+-- binding it to a port
+-- ( 0 => have the system pick next available port no.)
+udpSocket :: Int -> IO Socket
+udpSocket p = do
+ pr <- getProtocolNumber "udp"
+ s <- socket AF_INET Datagram pr
+ bindSocket s (SockAddrInet (mkPortNumber p) iNADDR_ANY)
+ return s
+#else
+reportCompile _ _ = return ()
+#endif
+
+\end{code}