X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Fmain%2FHscMain.lhs;h=b8d9266edfa1677b2ac9dd9c1ba76f40b80674e4;hb=868d7f6665bb6440ad8a462103b3809fffbd8ae7;hp=80397da7fdbc269e084aa7e702a6bae2484ff49a;hpb=e440a5e262dfa09fa02e4d69192948278e734387;p=ghc-hetmet.git diff --git a/ghc/compiler/main/HscMain.lhs b/ghc/compiler/main/HscMain.lhs index 80397da..b8d9266 100644 --- a/ghc/compiler/main/HscMain.lhs +++ b/ghc/compiler/main/HscMain.lhs @@ -5,283 +5,452 @@ \section[GHC_Main]{Main driver for Glasgow Haskell compiler} \begin{code} -module HscMain ( - HscResult(..), hscMain, initPersistentCompilerState +module HscMain + ( newHscEnv, hscCmmFile + , hscFileCheck + , hscParseIdentifier #ifdef GHCI - , hscStmt, hscTcExpr, hscThing, - , compileExpr + , hscStmt, hscTcExpr, hscKcType + , compileExpr #endif - ) where + , hscCompileOneShot -- :: Compiler HscStatus + , hscCompileMake -- :: Compiler (HscStatus, ModIface, ModDetails) + , hscCompileInteractive -- :: Compiler (InteractiveStatus, ModIface, ModDetails) + , HscStatus (..) + , InteractiveStatus (..) + , HscChecked (..) + ) where #include "HsVersions.h" #ifdef GHCI -import TcHsSyn ( TypecheckedHsExpr ) +import HsSyn ( Stmt(..), LHsExpr, LStmt, LHsType ) +import Module ( Module ) import CodeOutput ( outputForeignStubs ) import ByteCodeGen ( byteCodeGen, coreExprToBCOs ) import Linker ( HValue, linkExpr ) -import TidyPgm ( tidyCoreExpr ) +import CoreTidy ( tidyExpr ) import CorePrep ( corePrepExpr ) import Flattening ( flattenExpr ) -import TcRnDriver ( tcRnStmt, tcRnExpr, tcRnThing ) -import RdrHsSyn ( RdrNameStmt ) +import TcRnDriver ( tcRnStmt, tcRnExpr, tcRnType ) import Type ( Type ) import PrelNames ( iNTERACTIVE ) -import StringBuffer ( stringToStringBuffer ) -import Name ( Name ) +import Kind ( Kind ) import CoreLint ( lintUnfolding ) +import DsMeta ( templateHaskellNames ) +import SrcLoc ( noSrcLoc ) +import VarEnv ( emptyTidyEnv ) #endif -import HsSyn - -import RdrName ( nameRdrName ) -import Id ( idName ) -import IdInfo ( CafInfo(..), CgInfoEnv, CgInfo(..) ) -import StringBuffer ( hGetStringBuffer, freeStringBuffer ) +import Var ( Id ) +import Module ( emptyModuleEnv, ModLocation(..) ) +import RdrName ( GlobalRdrEnv, RdrName ) +import HsSyn ( HsModule, LHsBinds, HsGroup, LIE, LImportDecl ) +import SrcLoc ( Located(..) ) +import StringBuffer ( hGetStringBuffer, stringToStringBuffer ) import Parser -import Lex ( ParseResult(..), ExtFlags(..), mkPState ) -import SrcLoc ( mkSrcLoc, noSrcLoc ) -import TcRnDriver ( checkOldIface, tcRnModule, tcRnExtCore, tcRnIface ) -import RnEnv ( extendOrigNameCache ) -import Rules ( emptyRuleBase ) -import PrelInfo ( wiredInThingEnv, knownKeyNames ) -import PrelRules ( builtinRules ) -import MkIface ( mkIface ) -import InstEnv ( emptyInstEnv ) -import Desugar +import Lexer ( P(..), ParseResult(..), mkPState ) +import SrcLoc ( mkSrcLoc ) +import TcRnDriver ( tcRnModule, tcRnExtCore ) +import TcIface ( typecheckIface ) +import TcRnMonad ( initIfaceCheck, TcGblEnv(..) ) +import IfaceEnv ( initNameCache ) +import LoadIface ( ifaceStats, initExternalPackageState ) +import PrelInfo ( wiredInThings, basicKnownKeyNames ) +import MkIface ( checkOldIface, mkIface, writeIfaceFile ) +import Desugar ( deSugar, deSugarExpr ) import Flattening ( flatten ) -import SimplCore -import CoreUtils ( coreBindsSize ) -import TidyPgm ( tidyCorePgm ) +import SimplCore ( core2core, simplifyExpr ) +import TidyPgm ( tidyProgram, mkBootModDetails ) import CorePrep ( corePrepPgm ) -import StgSyn import CoreToStg ( coreToStg ) +import TyCon ( isDataTyCon ) +import Packages ( mkHomeModules ) +import Name ( Name, NamedThing(..) ) import SimplStg ( stg2stg ) import CodeGen ( codeGen ) +import CmmParse ( parseCmmFile ) import CodeOutput ( codeOutput ) -import Module ( emptyModuleEnv ) -import CmdLineOpts -import DriverPhases ( isExtCore_file ) -import ErrUtils ( dumpIfSet_dyn, showPass, printError ) +import DynFlags +import ErrUtils import UniqSupply ( mkSplitUniqSupply ) -import Bag ( consBag, emptyBag ) import Outputable import HscStats ( ppSourceStats ) import HscTypes import MkExternalCore ( emitExternalCore ) import ParserCore import ParserCoreUtils -import FiniteMap ( emptyFM ) -import Name ( nameModule ) -import NameEnv ( emptyNameEnv, mkNameEnv ) -import NameSet ( emptyNameSet ) -import Module ( Module, ModLocation(..), showModMsg ) import FastString import Maybes ( expectJust ) - -import DATA_IOREF ( newIORef, readIORef, writeIORef ) -import UNSAFE_IO ( unsafePerformIO ) - +import Bag ( unitBag ) import Monad ( when ) -import Maybe ( isJust, fromJust ) import IO +import DATA_IOREF ( newIORef, readIORef ) \end{code} %************************************************************************ %* * -\subsection{The main compiler pipeline} + Initialisation %* * %************************************************************************ \begin{code} -data HscResult - -- compilation failed - = HscFail PersistentCompilerState -- updated PCS - -- concluded that it wasn't necessary - | HscNoRecomp PersistentCompilerState -- updated PCS - ModDetails -- new details (HomeSymbolTable additions) - ModIface -- new iface (if any compilation was done) - -- did recompilation - | HscRecomp PersistentCompilerState -- updated PCS - ModDetails -- new details (HomeSymbolTable additions) - ModIface -- new iface (if any compilation was done) - Bool -- stub_h exists - Bool -- stub_c exists - (Maybe CompiledByteCode) - - -- no errors or warnings; the individual passes - -- (parse/rename/typecheck) print messages themselves - -hscMain - :: HscEnv - -> PersistentCompilerState -- IN: persistent compiler state - -> Module - -> ModLocation -- location info - -> Bool -- True <=> source unchanged - -> Bool -- True <=> have an object file (for msgs only) - -> Maybe ModIface -- old interface, if available - -> IO HscResult - -hscMain hsc_env pcs mod location - source_unchanged have_object maybe_old_iface - = do { - (pcs_ch, maybe_chk_result) <- _scc_ "checkOldIface" - checkOldIface hsc_env pcs mod - (ml_hi_file location) - source_unchanged maybe_old_iface; - case maybe_chk_result of { - Nothing -> return (HscFail pcs_ch) ; - Just (recomp_reqd, maybe_checked_iface) -> do { - - let no_old_iface = not (isJust maybe_checked_iface) - what_next | recomp_reqd || no_old_iface = hscRecomp - | otherwise = hscNoRecomp - - ; what_next hsc_env pcs_ch have_object - mod location maybe_checked_iface - }}} - - --- hscNoRecomp definitely expects to have the old interface available -hscNoRecomp hsc_env pcs_ch have_object - mod location (Just old_iface) - | hsc_mode hsc_env == OneShot - = do { - when (verbosity (hsc_dflags hsc_env) > 0) $ - hPutStrLn stderr "compilation IS NOT required"; - let { bomb = panic "hscNoRecomp:OneShot" }; - return (HscNoRecomp pcs_ch bomb bomb) - } - | otherwise - = do { - when (verbosity (hsc_dflags hsc_env) >= 1) $ - hPutStrLn stderr ("Skipping " ++ - showModMsg have_object mod location); - - -- Typecheck - (pcs_tc, maybe_tc_result) <- tcRnIface hsc_env pcs_ch old_iface ; - - case maybe_tc_result of { - Nothing -> return (HscFail pcs_tc); - Just new_details -> - - return (HscNoRecomp pcs_tc new_details old_iface) - }} +newHscEnv :: DynFlags -> IO HscEnv +newHscEnv dflags + = do { eps_var <- newIORef initExternalPackageState + ; us <- mkSplitUniqSupply 'r' + ; nc_var <- newIORef (initNameCache us knownKeyNames) + ; fc_var <- newIORef emptyModuleEnv + ; return (HscEnv { hsc_dflags = dflags, + hsc_targets = [], + hsc_mod_graph = [], + hsc_IC = emptyInteractiveContext, + hsc_HPT = emptyHomePackageTable, + hsc_EPS = eps_var, + hsc_NC = nc_var, + hsc_FC = fc_var } ) } + + +knownKeyNames :: [Name] -- Put here to avoid loops involving DsMeta, + -- where templateHaskellNames are defined +knownKeyNames = map getName wiredInThings + ++ basicKnownKeyNames +#ifdef GHCI + ++ templateHaskellNames +#endif +\end{code} + + +%************************************************************************ +%* * + The main compiler pipeline +%* * +%************************************************************************ -hscRecomp hsc_env pcs_ch have_object - mod location maybe_checked_iface - = do { - -- what target are we shooting for? - ; let one_shot = hsc_mode hsc_env == OneShot - ; let dflags = hsc_dflags hsc_env - ; let toInterp = dopt_HscLang dflags == HscInterpreted - ; let toCore = isJust (ml_hs_file location) && - isExtCore_file (fromJust (ml_hs_file location)) - - ; when (not one_shot && verbosity dflags >= 1) $ - hPutStrLn stderr ("Compiling " ++ - showModMsg (not toInterp) mod location); + -------------------------------- + The compilation proper + -------------------------------- + + +It's the task of the compilation proper to compile Haskell, hs-boot and +core files to either byte-code, hard-code (C, asm, Java, ect) or to +nothing at all (the module is still parsed and type-checked. This +feature is mostly used by IDE's and the likes). +Compilation can happen in either 'one-shot', 'make', or 'interactive' +mode. 'One-shot' mode targets hard-code, 'make' mode targets hard-code +and nothing, and 'interactive' mode targets byte-code. The modes are +kept separate because of their different types. +In 'one-shot' mode, we're only compiling a single file and can therefore +discard the new ModIface and ModDetails. This is also the reason it only +targets hard-code; compiling to byte-code or nothing doesn't make sense +when we discard the result. 'Make' mode is like 'one-shot' except that we +keep the resulting ModIface and ModDetails. 'Make' mode doesn't target +byte-code since that require us to return the newly compiled byte-code. +'Interactive' mode is similar to 'make' mode except that we return +the compiled byte-code together with the ModIface and ModDetails. +Trying to compile a hs-boot file to byte-code will result in a run-time +error. This is the only thing that isn't caught by the type-system. + +\begin{code} + +data HscChecked + = HscChecked + -- parsed + (Located (HsModule RdrName)) + -- renamed + (Maybe (HsGroup Name,[LImportDecl Name],Maybe [LIE Name])) + -- typechecked + (Maybe (LHsBinds Id, GlobalRdrEnv, ModDetails)) + + +-- Status of a compilation to hard-code or nothing. +data HscStatus + = HscNoRecomp + | HscRecomp Bool -- Has stub files. + -- This is a hack. We can't compile C files here + -- since it's done in DriverPipeline. For now we + -- just return True if we want the caller to compile + -- it for us. + +-- Status of a compilation to byte-code. +data InteractiveStatus + = InteractiveNoRecomp + | InteractiveRecomp Bool -- Same as HscStatus + CompiledByteCode + +type NoRecomp result = HscEnv -> ModSummary -> ModIface -> Maybe (Int,Int) -> IO result +type FrontEnd core = HscEnv -> ModSummary -> Maybe (Int,Int) -> IO (Maybe core) +type BackEnd core prepCore = HscEnv -> ModSummary -> Maybe ModIface -> core -> IO prepCore +type CodeGen prepCore result = HscEnv -> ModSummary -> prepCore -> IO result + +-- FIXME: The old interface and module index are only using in 'make' and +-- 'interactive' mode. They should be removed from 'oneshot' mode. +type Compiler result = HscEnv + -> ModSummary + -> Bool -- True <=> source unchanged + -> Maybe ModIface -- Old interface, if available + -> Maybe (Int,Int) -- Just (i,n) <=> module i of n (for msgs) + -> IO (Maybe result) + + +-- This functions checks if recompilation is necessary and +-- then combines the FrontEnd, BackEnd and CodeGen to a +-- working compiler. +hscMkCompiler :: NoRecomp result -- What to do when recompilation isn't required. + -> FrontEnd core + -> BackEnd core prepCore + -> CodeGen prepCore result + -> Compiler result +hscMkCompiler norecomp frontend backend codegen + hsc_env mod_summary source_unchanged + mbOldIface mbModIndex + = do (recomp_reqd, mbCheckedIface) + <- {-# SCC "checkOldIface" #-} + checkOldIface hsc_env mod_summary + source_unchanged mbOldIface + case mbCheckedIface of + Just iface | not recomp_reqd + -> do result <- norecomp hsc_env mod_summary iface mbModIndex + return (Just result) + _otherwise + -> do mbCore <- frontend hsc_env mod_summary mbModIndex + case mbCore of + Nothing + -> return Nothing + Just core + -> do prepCore <- backend hsc_env mod_summary + mbCheckedIface core + result <- codegen hsc_env mod_summary prepCore + return (Just result) + +-------------------------------------------------------------- +-- Compilers +-------------------------------------------------------------- + +-- Compile Haskell, boot and extCore in OneShot mode. +hscCompileOneShot :: Compiler HscStatus +hscCompileOneShot hsc_env mod_summary = + compiler hsc_env mod_summary + where mkComp = hscMkCompiler (norecompOneShot HscNoRecomp) + compiler + = case ms_hsc_src mod_summary of + ExtCoreFile + -> mkComp hscCoreFrontEnd hscNewBackEnd hscCodeGenOneShot +-- 1 2 3 4 5 6 7 8 9 + HsSrcFile + -> mkComp hscFileFrontEnd hscNewBackEnd hscCodeGenOneShot + HsBootFile + -> mkComp hscFileFrontEnd hscNewBootBackEnd + (hscCodeGenConst (HscRecomp False)) + +-- Compile Haskell, boot and extCore in --make mode. +hscCompileMake :: Compiler (HscStatus, ModIface, ModDetails) +hscCompileMake hsc_env mod_summary + = compiler hsc_env mod_summary + where mkComp = hscMkCompiler norecompMake + backend = case hscTarget (hsc_dflags hsc_env) of + HscNothing -> hscCodeGenNothing + _other -> hscCodeGenMake + compiler + = case ms_hsc_src mod_summary of + ExtCoreFile + -> mkComp hscCoreFrontEnd hscNewBackEnd backend + HsSrcFile + -> mkComp hscFileFrontEnd hscNewBackEnd backend + HsBootFile + -> mkComp hscFileFrontEnd hscNewBootBackEnd hscCodeGenIdentity + + +-- Compile Haskell, extCore to bytecode. +hscCompileInteractive :: Compiler (InteractiveStatus, ModIface, ModDetails) +hscCompileInteractive hsc_env mod_summary = + hscMkCompiler norecompInteractive frontend hscNewBackEnd hscCodeGenInteractive + hsc_env mod_summary + where frontend = case ms_hsc_src mod_summary of + ExtCoreFile -> hscCoreFrontEnd + HsSrcFile -> hscFileFrontEnd + HsBootFile -> panic bootErrorMsg + bootErrorMsg = "Compiling a HsBootFile to bytecode doesn't make sense. " ++ + "Use 'hscCompileMake' instead." + +-------------------------------------------------------------- +-- NoRecomp handlers +-------------------------------------------------------------- + +norecompOneShot :: a -> NoRecomp a +norecompOneShot a hsc_env mod_summary + old_iface + mb_mod_index + = do compilationProgressMsg (hsc_dflags hsc_env) $ + "compilation IS NOT required" + dumpIfaceStats hsc_env + return a + +norecompMake :: NoRecomp (HscStatus, ModIface, ModDetails) +norecompMake = norecompWorker HscNoRecomp False + +norecompInteractive :: NoRecomp (InteractiveStatus, ModIface, ModDetails) +norecompInteractive = norecompWorker InteractiveNoRecomp True + +norecompWorker :: a -> Bool -> NoRecomp (a, ModIface, ModDetails) +norecompWorker a isInterp hsc_env mod_summary + old_iface mb_mod_index + = do compilationProgressMsg (hsc_dflags hsc_env) $ + (showModuleIndex mb_mod_index ++ + "Skipping " ++ showModMsg isInterp mod_summary) + new_details <- {-# SCC "tcRnIface" #-} + initIfaceCheck hsc_env $ + typecheckIface old_iface + dumpIfaceStats hsc_env + return (a, old_iface, new_details) + +-------------------------------------------------------------- +-- FrontEnds +-------------------------------------------------------------- + +hscCoreFrontEnd :: FrontEnd ModGuts +hscCoreFrontEnd hsc_env mod_summary mb_mod_index = do { + ------------------- + -- PARSE + ------------------- + ; inp <- readFile (expectJust "hscCoreFrontEnd" (ms_hspp_file mod_summary)) + ; case parseCore inp 1 of + FailP s -> do errorMsg (hsc_dflags hsc_env) (text s{-ToDo: wrong-}) + return Nothing + OkP rdr_module -> do { + + ------------------- + -- RENAME and TYPECHECK + ------------------- + ; (tc_msgs, maybe_tc_result) <- {-# SCC "TypeCheck" #-} + tcRnExtCore hsc_env rdr_module + ; printErrorsAndWarnings (hsc_dflags hsc_env) tc_msgs + ; case maybe_tc_result of + Nothing -> return Nothing + Just mod_guts -> return (Just mod_guts) -- No desugaring to do! + }} + + +hscFileFrontEnd :: FrontEnd ModGuts +hscFileFrontEnd hsc_env mod_summary mb_mod_index = do { +-- FIXME: Move 'DISPLAY PROGRESS MESSAGE' out of the frontend. + ------------------- + -- DISPLAY PROGRESS MESSAGE + ------------------- + ; let dflags = hsc_dflags hsc_env + one_shot = isOneShot (ghcMode dflags) + toInterp = hscTarget dflags == HscInterpreted + ; when (not one_shot) $ + compilationProgressMsg dflags $ + (showModuleIndex mb_mod_index ++ + "Compiling " ++ showModMsg (not toInterp) mod_summary) - ; front_res <- if toCore then - hscCoreFrontEnd hsc_env pcs_ch location - else - hscFrontEnd hsc_env pcs_ch location + ------------------- + -- PARSE + ------------------- + ; let hspp_file = expectJust "hscFileFrontEnd" (ms_hspp_file mod_summary) + hspp_buf = ms_hspp_buf mod_summary + + ; maybe_parsed <- myParseModule dflags hspp_file hspp_buf + + ; case maybe_parsed of { + Left err -> do { printBagOfErrors dflags (unitBag err) + ; return Nothing } ; + Right rdr_module -> do { + + ------------------- + -- RENAME and TYPECHECK + ------------------- + (tc_msgs, maybe_tc_result) + <- {-# SCC "Typecheck-Rename" #-} + tcRnModule hsc_env (ms_hsc_src mod_summary) False rdr_module + + ; printErrorsAndWarnings dflags tc_msgs + ; case maybe_tc_result of { + Nothing -> return Nothing ; + Just tc_result -> do { + + ------------------- + -- DESUGAR + ------------------- + ; (warns, maybe_ds_result) <- {-# SCC "DeSugar" #-} + deSugar hsc_env tc_result + ; printBagOfWarnings dflags warns + ; return maybe_ds_result + }}}}} + +-------------------------------------------------------------- +-- BackEnds +-------------------------------------------------------------- + +-- FIXME: Rename backend to simplifier, and codegen to backend. - ; case front_res of - Left flure -> return flure; - Right (pcs_tc, ds_result) -> do { +hscNewBootBackEnd :: BackEnd ModGuts (HscStatus, ModIface, ModDetails) +hscNewBootBackEnd hsc_env mod_summary maybe_old_iface ds_result + = do details <- mkBootModDetails hsc_env ds_result + (new_iface, no_change) + <- {-# SCC "MkFinalIface" #-} + mkIface hsc_env maybe_old_iface ds_result details + writeIfaceFile hsc_env (ms_location mod_summary) new_iface no_change + -- And the answer is ... + dumpIfaceStats hsc_env + return (HscRecomp False, new_iface, details) +hscNewBackEnd :: BackEnd ModGuts (ModIface, ModDetails, CgGuts) +hscNewBackEnd hsc_env mod_summary maybe_old_iface ds_result + = do { -- OMITTED: + -- ; seqList imported_modules (return ()) - -- OMITTED: - -- ; seqList imported_modules (return ()) + let dflags = hsc_dflags hsc_env ------------------- -- FLATTENING ------------------- - ; flat_result <- _scc_ "Flattening" - flatten hsc_env pcs_tc ds_result - - ; let pcs_middle = pcs_tc - -{- Again, omit this because it loses the usage info - which is needed in mkIface. Maybe we should compute - usage info earlier. - - ; pcs_middle - <- _scc_ "pcs_middle" - if one_shot then - do init_pcs <- initPersistentCompilerState - init_prs <- initPersistentRenamerState - let - rules = pcs_rules pcs_tc - orig_tc = prsOrig (pcs_PRS pcs_tc) - new_prs = init_prs{ prsOrig=orig_tc } - - orig_tc `seq` rules `seq` new_prs `seq` - return init_pcs{ pcs_PRS = new_prs, - pcs_rules = rules } - else return pcs_tc --} + ; flat_result <- {-# SCC "Flattening" #-} + flatten hsc_env ds_result + + +{- TEMP: need to review space-leak fixing here + NB: even the code generator can force one of the + thunks for constructor arguments, for newtypes in particular + + ; let -- Rule-base accumulated from imported packages + pkg_rule_base = eps_rule_base (hsc_EPS hsc_env) --- Should we remove bits of flat_result at this point? --- ; flat_result <- case flat_result of --- ModResult { md_binds = binds } -> --- return ModDetails { md_binds = binds, --- md_rules = [], --- md_types = emptyTypeEnv, --- md_insts = [] } + -- In one-shot mode, ZAP the external package state at + -- this point, because we aren't going to need it from + -- now on. We keep the name cache, however, because + -- tidyCore needs it. + pcs_middle + | one_shot = pcs_tc{ pcs_EPS = error "pcs_EPS missing" } + | otherwise = pcs_tc + + ; pkg_rule_base `seq` pcs_middle `seq` return () +-} -- alive at this point: -- pcs_middle -- flat_result + -- pkg_rule_base ------------------- -- SIMPLIFY ------------------- - ; simpl_result <- _scc_ "Core2Core" - core2core hsc_env pcs_middle flat_result + ; simpl_result <- {-# SCC "Core2Core" #-} + core2core hsc_env flat_result ------------------- -- TIDY ------------------- - ; cg_info_ref <- newIORef Nothing ; - ; let cg_info :: CgInfoEnv - cg_info = unsafePerformIO $ do { - maybe_cg_env <- readIORef cg_info_ref ; - case maybe_cg_env of - Just env -> return env - Nothing -> do { printError "Urk! Looked at CgInfo too early!"; - return emptyNameEnv } } - -- cg_info_ref will be filled in just after restOfCodeGeneration - -- Meanwhile, tidyCorePgm is careful not to look at cg_info! - - ; (pcs_simpl, tidy_result) - <- _scc_ "CoreTidy" - tidyCorePgm dflags pcs_middle cg_info simpl_result - --- Space-saving ploy doesn't work so well now --- because mkIface needs the populated PIT to --- generate usage info. Maybe we should re-visit this. --- ; pcs_final <- if one_shot then initPersistentCompilerState --- else return pcs_simpl - ; let pcs_final = pcs_simpl + ; (cg_guts, details) <- {-# SCC "CoreTidy" #-} + tidyProgram hsc_env simpl_result -- Alive at this point: -- tidy_result, pcs_final - - ------------------- - -- PREPARE FOR CODE GENERATION - -- Do saturation and convert to A-normal form - ; prepd_result <- _scc_ "CorePrep" - corePrepPgm dflags tidy_result - - ------------------- - -- CONVERT TO STG and COMPLETE CODE GENERATION - ; (stub_h_exists, stub_c_exists, maybe_bcos) - <- hscBackEnd dflags cg_info_ref prepd_result + -- hsc_env ------------------- -- BUILD THE NEW ModIface and ModDetails @@ -289,133 +458,200 @@ hscRecomp hsc_env pcs_ch have_object -- This has to happen *after* code gen so that the back-end -- info has been set. Not yet clear if it matters waiting -- until after code output - ; final_iface <- _scc_ "MkFinalIface" - mkIface hsc_env location - maybe_checked_iface tidy_result - ; let final_details = ModDetails { md_types = mg_types tidy_result, - md_insts = mg_insts tidy_result, - md_rules = mg_rules tidy_result } - ; emitExternalCore dflags tidy_result - - -- and the answer is ... - ; return (HscRecomp pcs_final - final_details - final_iface - stub_h_exists stub_c_exists - maybe_bcos) - }} - -hscCoreFrontEnd hsc_env pcs_ch location = do { - ------------------- - -- PARSE - ------------------- - ; inp <- readFile (expectJust "hscCoreFrontEnd:hspp" (ml_hspp_file location)) - ; case parseCore inp 1 of - FailP s -> hPutStrLn stderr s >> return (Left (HscFail pcs_ch)); - OkP rdr_module -> do { - - ------------------- - -- RENAME and TYPECHECK + ; (new_iface, no_change) + <- {-# SCC "MkFinalIface" #-} + mkIface hsc_env maybe_old_iface simpl_result details + + ; writeIfaceFile hsc_env (ms_location mod_summary) new_iface no_change + + -- Emit external core + ; emitExternalCore dflags cg_guts + ------------------- - ; (pcs_tc, maybe_tc_result) <- _scc_ "TypeCheck" - tcRnExtCore hsc_env pcs_ch rdr_module - ; case maybe_tc_result of { - Nothing -> return (Left (HscFail pcs_tc)); - Just mod_guts -> return (Right (pcs_tc, mod_guts)) - -- No desugaring to do! - }}} - + -- Return the prepared code. + ; return (new_iface, details, cg_guts) + } + +-------------------------------------------------------------- +-- Code generators +-------------------------------------------------------------- + +-- Don't output any code. +hscCodeGenNothing :: CodeGen (ModIface, ModDetails, CgGuts) (HscStatus, ModIface, ModDetails) +hscCodeGenNothing hsc_env mod_summary (iface, details, cgguts) + = return (HscRecomp False, iface, details) + +-- Generate code and return both the new ModIface and the ModDetails. +hscCodeGenMake :: CodeGen (ModIface, ModDetails, CgGuts) (HscStatus, ModIface, ModDetails) +hscCodeGenMake hsc_env mod_summary (iface, details, cgguts) + = do hasStub <- hscCodeGenCompile hsc_env mod_summary cgguts + return (HscRecomp hasStub, iface, details) + +-- Here we don't need the ModIface and ModDetails anymore. +hscCodeGenOneShot :: CodeGen (ModIface, ModDetails, CgGuts) HscStatus +hscCodeGenOneShot hsc_env mod_summary (_, _, cgguts) + = do hasStub <- hscCodeGenCompile hsc_env mod_summary cgguts + return (HscRecomp hasStub) + +hscCodeGenCompile :: CodeGen CgGuts Bool +hscCodeGenCompile hsc_env mod_summary cgguts + = do let CgGuts{ -- This is the last use of the ModGuts in a compilation. + -- From now on, we just use the bits we need. + cg_module = this_mod, + cg_binds = core_binds, + cg_tycons = tycons, + cg_dir_imps = dir_imps, + cg_foreign = foreign_stubs, + cg_home_mods = home_mods, + cg_dep_pkgs = dependencies } = cgguts + dflags = hsc_dflags hsc_env + location = ms_location mod_summary + data_tycons = filter isDataTyCon tycons + -- cg_tycons includes newtypes, for the benefit of External Core, + -- but we don't generate any code for newtypes + + ------------------- + -- PREPARE FOR CODE GENERATION + -- Do saturation and convert to A-normal form + prepd_binds <- {-# SCC "CorePrep" #-} + corePrepPgm dflags core_binds data_tycons ; + ----------------- Convert to STG ------------------ + (stg_binds, cost_centre_info) + <- {-# SCC "CoreToStg" #-} + myCoreToStg dflags home_mods this_mod prepd_binds + ------------------ Code generation ------------------ + abstractC <- {-# SCC "CodeGen" #-} + codeGen dflags home_mods this_mod data_tycons + foreign_stubs dir_imps cost_centre_info + stg_binds + ------------------ Code output ----------------------- + (stub_h_exists,stub_c_exists) + <- codeOutput dflags this_mod location foreign_stubs + dependencies abstractC + return stub_c_exists + +hscCodeGenIdentity :: CodeGen a a +hscCodeGenIdentity hsc_env mod_summary a = return a + +hscCodeGenConst :: b -> CodeGen a b +hscCodeGenConst b hsc_env mod_summary a = return b + +hscCodeGenInteractive :: CodeGen (ModIface, ModDetails, CgGuts) + (InteractiveStatus, ModIface, ModDetails) +hscCodeGenInteractive hsc_env mod_summary (iface, details, cgguts) +#ifdef GHCI + = do let CgGuts{ -- This is the last use of the ModGuts in a compilation. + -- From now on, we just use the bits we need. + cg_module = this_mod, + cg_binds = core_binds, + cg_tycons = tycons, + cg_foreign = foreign_stubs, + cg_home_mods = home_mods, + cg_dep_pkgs = dependencies } = cgguts + dflags = hsc_dflags hsc_env + location = ms_location mod_summary + data_tycons = filter isDataTyCon tycons + -- cg_tycons includes newtypes, for the benefit of External Core, + -- but we don't generate any code for newtypes + + ------------------- + -- PREPARE FOR CODE GENERATION + -- Do saturation and convert to A-normal form + prepd_binds <- {-# SCC "CorePrep" #-} + corePrepPgm dflags core_binds data_tycons ; + ----------------- Generate byte code ------------------ + comp_bc <- byteCodeGen dflags prepd_binds data_tycons + ------------------ Create f-x-dynamic C-side stuff --- + (istub_h_exists, istub_c_exists) + <- outputForeignStubs dflags this_mod location foreign_stubs + return (InteractiveRecomp istub_c_exists comp_bc, iface, details) +#else + = panic "GHC not compiled with interpreter" +#endif + + +------------------------------ -hscFrontEnd hsc_env pcs_ch location = do { +hscFileCheck :: HscEnv -> ModSummary -> IO (Maybe HscChecked) +hscFileCheck hsc_env mod_summary = do { ------------------- -- PARSE ------------------- - ; maybe_parsed <- myParseModule (hsc_dflags hsc_env) - (expectJust "hscFrontEnd:hspp" (ml_hspp_file location)) + ; let dflags = hsc_dflags hsc_env + hspp_file = expectJust "hscFileFrontEnd" (ms_hspp_file mod_summary) + hspp_buf = ms_hspp_buf mod_summary + + ; maybe_parsed <- myParseModule dflags hspp_file hspp_buf ; case maybe_parsed of { - Nothing -> return (Left (HscFail pcs_ch)); - Just rdr_module -> do { - + Left err -> do { printBagOfErrors dflags (unitBag err) + ; return Nothing } ; + Right rdr_module -> do { + ------------------- -- RENAME and TYPECHECK ------------------- - ; (pcs_tc, maybe_tc_result) <- _scc_ "Typecheck and Rename" - tcRnModule hsc_env pcs_ch rdr_module + (tc_msgs, maybe_tc_result) + <- _scc_ "Typecheck-Rename" + tcRnModule hsc_env (ms_hsc_src mod_summary) + True{-save renamed syntax-} + rdr_module + + ; printErrorsAndWarnings dflags tc_msgs ; case maybe_tc_result of { - Nothing -> return (Left (HscFail pcs_ch)); - Just tc_result -> do { + Nothing -> return (Just (HscChecked rdr_module Nothing Nothing)); + Just tc_result -> do + let md = ModDetails { + md_types = tcg_type_env tc_result, + md_exports = tcg_exports tc_result, + md_insts = tcg_insts tc_result, + md_rules = [panic "no rules"] } + -- Rules are CoreRules, not the + -- RuleDecls we get out of the typechecker + rnInfo = do decl <- tcg_rn_decls tc_result + imports <- tcg_rn_imports tc_result + let exports = tcg_rn_exports tc_result + return (decl,imports,exports) + return (Just (HscChecked rdr_module + rnInfo + (Just (tcg_binds tc_result, + tcg_rdr_env tc_result, + md)))) + }}}} + + +hscCmmFile :: DynFlags -> FilePath -> IO Bool +hscCmmFile dflags filename = do + maybe_cmm <- parseCmmFile dflags (mkHomeModules []) filename + case maybe_cmm of + Nothing -> return False + Just cmm -> do + codeOutput dflags no_mod no_loc NoStubs [] [cmm] + return True + where + no_mod = panic "hscCmmFile: no_mod" + no_loc = ModLocation{ ml_hs_file = Just filename, + ml_hi_file = panic "hscCmmFile: no hi file", + ml_obj_file = panic "hscCmmFile: no obj file" } - ------------------- - -- DESUGAR - ------------------- - ; ds_result <- _scc_ "DeSugar" - deSugar hsc_env pcs_tc tc_result - ; return (Right (pcs_tc, ds_result)) - }}}}} +myParseModule dflags src_filename maybe_src_buf + = -------------------------- Parser ---------------- + showPass dflags "Parser" >> + {-# SCC "Parser" #-} do -hscBackEnd dflags cg_info_ref prepd_result - = case dopt_HscLang dflags of - HscNothing -> return (False, False, Nothing) + -- sometimes we already have the buffer in memory, perhaps + -- because we needed to parse the imports out of it, or get the + -- module name. + buf <- case maybe_src_buf of + Just b -> return b + Nothing -> hGetStringBuffer src_filename - HscInterpreted -> -#ifdef GHCI - do ----------------- Generate byte code ------------------ - comp_bc <- byteCodeGen dflags prepd_result - - -- Fill in the code-gen info - writeIORef cg_info_ref (Just emptyNameEnv) - - ------------------ Create f-x-dynamic C-side stuff --- - (istub_h_exists, istub_c_exists) - <- outputForeignStubs dflags (mg_foreign prepd_result) - - return ( istub_h_exists, istub_c_exists, - Just comp_bc ) -#else - panic "GHC not compiled with interpreter" -#endif + let loc = mkSrcLoc (mkFastString src_filename) 1 0 - other -> - do - ----------------- Convert to STG ------------------ - (stg_binds, cost_centre_info, stg_back_end_info) - <- _scc_ "CoreToStg" - myCoreToStg dflags prepd_result - - -- Fill in the code-gen info for the earlier tidyCorePgm - writeIORef cg_info_ref (Just stg_back_end_info) - - ------------------ Code generation ------------------ - abstractC <- _scc_ "CodeGen" - codeGen dflags prepd_result - cost_centre_info stg_binds - - ------------------ Code output ----------------------- - (stub_h_exists, stub_c_exists) - <- codeOutput dflags prepd_result abstractC - - return (stub_h_exists, stub_c_exists, Nothing) - - -myParseModule dflags src_filename - = do -------------------------- Parser ---------------- - showPass dflags "Parser" - _scc_ "Parser" do - buf <- hGetStringBuffer src_filename - - let exts = ExtFlags {glasgowExtsEF = dopt Opt_GlasgowExts dflags, - ffiEF = dopt Opt_FFI dflags, - withEF = dopt Opt_With dflags, - parrEF = dopt Opt_PArr dflags} - loc = mkSrcLoc (mkFastString src_filename) 1 - - case parseModule buf (mkPState loc exts) of { - - PFailed err -> do { hPutStrLn stderr (showSDoc err); - freeStringBuffer buf; - return Nothing }; + case unP parseModule (mkPState buf loc dflags) of { + + PFailed span err -> return (Left (mkPlainErrMsg span err)); POk _ rdr_module -> do { @@ -424,35 +660,20 @@ myParseModule dflags src_filename dumpIfSet_dyn dflags Opt_D_source_stats "Source Statistics" (ppSourceStats False rdr_module) ; - return (Just rdr_module) + return (Right rdr_module) -- ToDo: free the string buffer later. }} -myCoreToStg dflags (ModGuts {mg_module = this_mod, mg_binds = tidy_binds}) +myCoreToStg dflags home_mods this_mod prepd_binds = do - () <- coreBindsSize tidy_binds `seq` return () - -- TEMP: the above call zaps some space usage allocated by the - -- simplifier, which for reasons I don't understand, persists - -- thoroughout code generation -- JRS - -- - -- This is still necessary. -- SDM (10 Dec 2001) - - stg_binds <- _scc_ "Core2Stg" - coreToStg dflags tidy_binds - - (stg_binds2, cost_centre_info) <- _scc_ "Core2Stg" - stg2stg dflags this_mod stg_binds - - let env_rhs :: CgInfoEnv - env_rhs = mkNameEnv [ caf_info `seq` (idName bndr, CgInfo caf_info) - | (bind,_) <- stg_binds2, - let caf_info - | stgBindHasCafRefs bind = MayHaveCafRefs - | otherwise = NoCafRefs, - bndr <- stgBinders bind ] - - return (stg_binds2, cost_centre_info, env_rhs) + stg_binds <- {-# SCC "Core2Stg" #-} + coreToStg home_mods prepd_binds + + (stg_binds2, cost_centre_info) <- {-# SCC "Stg2Stg" #-} + stg2stg dflags home_mods this_mod stg_binds + + return (stg_binds2, cost_centre_info) \end{code} @@ -492,136 +713,103 @@ A naked expression returns a singleton Name [it]. #ifdef GHCI hscStmt -- Compile a stmt all the way to an HValue, but don't run it :: HscEnv - -> PersistentCompilerState -- IN: persistent compiler state - -> InteractiveContext -- Context for compiling -> String -- The statement - -> IO ( PersistentCompilerState, - Maybe (InteractiveContext, [Name], HValue) ) + -> IO (Maybe (HscEnv, [Name], HValue)) -hscStmt hsc_env pcs icontext stmt +hscStmt hsc_env stmt = do { maybe_stmt <- hscParseStmt (hsc_dflags hsc_env) stmt ; case maybe_stmt of { - Nothing -> return (pcs, Nothing) ; - Just parsed_stmt -> do { + Nothing -> return Nothing ; -- Parse error + Just Nothing -> return Nothing ; -- Empty line + Just (Just parsed_stmt) -> do { -- The real stuff -- Rename and typecheck it - (pcs1, maybe_tc_result) - <- tcRnStmt hsc_env pcs icontext parsed_stmt + let icontext = hsc_IC hsc_env + ; maybe_tc_result <- tcRnStmt hsc_env icontext parsed_stmt ; case maybe_tc_result of { - Nothing -> return (pcs1, Nothing) ; + Nothing -> return Nothing ; Just (new_ic, bound_names, tc_expr) -> do { -- Then desugar, code gen, and link it - ; hval <- compileExpr hsc_env pcs1 iNTERACTIVE + ; hval <- compileExpr hsc_env iNTERACTIVE (ic_rn_gbl_env new_ic) (ic_type_env new_ic) tc_expr - ; return (pcs1, Just (new_ic, bound_names, hval)) + ; return (Just (hsc_env{ hsc_IC=new_ic }, bound_names, hval)) }}}}} hscTcExpr -- Typecheck an expression (but don't run it) :: HscEnv - -> PersistentCompilerState -- IN: persistent compiler state - -> InteractiveContext -- Context for compiling -> String -- The expression - -> IO (PersistentCompilerState, Maybe Type) + -> IO (Maybe Type) -hscTcExpr hsc_env pcs icontext expr +hscTcExpr hsc_env expr = do { maybe_stmt <- hscParseStmt (hsc_dflags hsc_env) expr + ; let icontext = hsc_IC hsc_env ; case maybe_stmt of { - Just (ExprStmt expr _ _) - -> tcRnExpr hsc_env pcs icontext expr ; - Just other -> do { hPutStrLn stderr ("not an expression: `" ++ expr ++ "'") ; - return (pcs, Nothing) } ; - Nothing -> return (pcs, Nothing) } } + Nothing -> return Nothing ; -- Parse error + Just (Just (L _ (ExprStmt expr _ _))) + -> tcRnExpr hsc_env icontext expr ; + Just other -> do { errorMsg (hsc_dflags hsc_env) (text "not an expression:" <+> quotes (text expr)) ; + return Nothing } ; + } } + +hscKcType -- Find the kind of a type + :: HscEnv + -> String -- The type + -> IO (Maybe Kind) + +hscKcType hsc_env str + = do { maybe_type <- hscParseType (hsc_dflags hsc_env) str + ; let icontext = hsc_IC hsc_env + ; case maybe_type of { + Just ty -> tcRnType hsc_env icontext ty ; + Just other -> do { errorMsg (hsc_dflags hsc_env) (text "not an type:" <+> quotes (text str)) ; + return Nothing } ; + Nothing -> return Nothing } } +#endif \end{code} \begin{code} -hscParseStmt :: DynFlags -> String -> IO (Maybe RdrNameStmt) -hscParseStmt dflags str - = do showPass dflags "Parser" - _scc_ "Parser" do +#ifdef GHCI +hscParseStmt :: DynFlags -> String -> IO (Maybe (Maybe (LStmt RdrName))) +hscParseStmt = hscParseThing parseStmt - buf <- stringToStringBuffer str +hscParseType :: DynFlags -> String -> IO (Maybe (LHsType RdrName)) +hscParseType = hscParseThing parseType +#endif + +hscParseIdentifier :: DynFlags -> String -> IO (Maybe (Located RdrName)) +hscParseIdentifier = hscParseThing parseIdentifier + +hscParseThing :: Outputable thing + => Lexer.P thing + -> DynFlags -> String + -> IO (Maybe thing) + -- Nothing => Parse error (message already printed) + -- Just x => success +hscParseThing parser dflags str + = showPass dflags "Parser" >> + {-# SCC "Parser" #-} do - let exts = ExtFlags {glasgowExtsEF = dopt Opt_GlasgowExts dflags, - ffiEF = dopt Opt_FFI dflags, - withEF = dopt Opt_With dflags, - parrEF = dopt Opt_PArr dflags} - loc = mkSrcLoc FSLIT("") 1 + buf <- stringToStringBuffer str - case parseStmt buf (mkPState loc exts) of { + let loc = mkSrcLoc FSLIT("") 1 0 - PFailed err -> do { hPutStrLn stderr (showSDoc err); --- Not yet implemented in <4.11 freeStringBuffer buf; - return Nothing }; + case unP parser (mkPState buf loc dflags) of { - -- no stmt: the line consisted of just space or comments - POk _ Nothing -> return Nothing; + PFailed span err -> do { printError span err; + return Nothing }; - POk _ (Just rdr_stmt) -> do { + POk _ thing -> do { --ToDo: can't free the string buffer until we've finished this -- compilation sweep and all the identifiers have gone away. - --freeStringBuffer buf; - dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" (ppr rdr_stmt); - return (Just rdr_stmt) + dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" (ppr thing); + return (Just thing) }} -#endif -\end{code} - -%************************************************************************ -%* * -\subsection{Getting information about an identifer} -%* * -%************************************************************************ - -\begin{code} -#ifdef GHCI -hscThing -- like hscStmt, but deals with a single identifier - :: HscEnv - -> PersistentCompilerState -- IN: persistent compiler state - -> InteractiveContext -- Context for compiling - -> String -- The identifier - -> IO ( PersistentCompilerState, - [TyThing] ) - -hscThing hsc_env pcs0 ic str - = do let dflags = hsc_dflags hsc_env - - maybe_rdr_name <- myParseIdentifier dflags str - case maybe_rdr_name of { - Nothing -> return (pcs0, []); - Just rdr_name -> do - - (pcs1, maybe_tc_result) <- - tcRnThing hsc_env pcs0 ic rdr_name - - case maybe_tc_result of { - Nothing -> return (pcs1, []) ; - Just things -> return (pcs1, things) - }} - -myParseIdentifier dflags str - = do buf <- stringToStringBuffer str - - let exts = ExtFlags {glasgowExtsEF = dopt Opt_GlasgowExts dflags, - ffiEF = dopt Opt_FFI dflags, - withEF = dopt Opt_With dflags, - parrEF = dopt Opt_PArr dflags} - loc = mkSrcLoc FSLIT("") 1 - - case parseIdentifier buf (mkPState loc exts) of - - PFailed err -> do { hPutStrLn stderr (showSDoc err); - freeStringBuffer buf; - return Nothing } - - POk _ rdr_name -> do { --should, but can't: freeStringBuffer buf; - return (Just rdr_name) } -#endif \end{code} %************************************************************************ @@ -633,26 +821,25 @@ myParseIdentifier dflags str \begin{code} #ifdef GHCI compileExpr :: HscEnv - -> PersistentCompilerState -> Module -> GlobalRdrEnv -> TypeEnv - -> TypecheckedHsExpr + -> LHsExpr Id -> IO HValue -compileExpr hsc_env pcs this_mod rdr_env type_env tc_expr +compileExpr hsc_env this_mod rdr_env type_env tc_expr = do { let { dflags = hsc_dflags hsc_env ; lint_on = dopt Opt_DoCoreLinting dflags } -- Desugar it - ; ds_expr <- deSugarExpr hsc_env pcs this_mod rdr_env type_env tc_expr + ; ds_expr <- deSugarExpr hsc_env this_mod rdr_env type_env tc_expr -- Flatten it - ; flat_expr <- flattenExpr hsc_env pcs ds_expr + ; flat_expr <- flattenExpr hsc_env ds_expr -- Simplify it ; simpl_expr <- simplifyExpr dflags flat_expr -- Tidy it (temporary, until coreSat does cloning) - ; tidy_expr <- tidyCoreExpr simpl_expr + ; let tidy_expr = tidyExpr emptyTidyEnv simpl_expr -- Prepare for codegen ; prepd_expr <- corePrepExpr dflags tidy_expr @@ -670,7 +857,7 @@ compileExpr hsc_env pcs this_mod rdr_env type_env tc_expr ; bcos <- coreExprToBCOs dflags prepd_expr -- link it - ; hval <- linkExpr hsc_env pcs bcos + ; hval <- linkExpr hsc_env bcos ; return hval } @@ -680,47 +867,35 @@ compileExpr hsc_env pcs this_mod rdr_env type_env tc_expr %************************************************************************ %* * -\subsection{Initial persistent state} + Statistics on reading interfaces %* * %************************************************************************ \begin{code} -initPersistentCompilerState :: IO PersistentCompilerState -initPersistentCompilerState - = do nc <- initNameCache - return ( - PCS { pcs_EPS = initExternalPackageState, - pcs_nc = nc }) - -initNameCache :: IO NameCache - = do us <- mkSplitUniqSupply 'r' - return (NameCache { nsUniqs = us, - nsNames = initOrigNames, - nsIPs = emptyFM }) - -initExternalPackageState :: ExternalPackageState -initExternalPackageState - = EPS { - eps_decls = (emptyNameEnv, 0), - eps_insts = (emptyBag, 0), - eps_inst_gates = emptyNameSet, - eps_rules = foldr add_rule (emptyBag, 0) builtinRules, - - eps_PIT = emptyPackageIfaceTable, - eps_PTE = wiredInThingEnv, - eps_inst_env = emptyInstEnv, - eps_rule_base = emptyRuleBase } - +dumpIfaceStats :: HscEnv -> IO () +dumpIfaceStats hsc_env + = do { eps <- readIORef (hsc_EPS hsc_env) + ; dumpIfSet (dump_if_trace || dump_rn_stats) + "Interface statistics" + (ifaceStats eps) } where - add_rule (name,rule) (rules, n_slurped) - = (gated_decl `consBag` rules, n_slurped) - where - gated_decl = (gate_fn, (mod, IfaceRuleOut rdr_name rule)) - mod = nameModule name - rdr_name = nameRdrName name -- Seems a bit of a hack to go back - -- to the RdrName - gate_fn vis_fn = vis_fn name -- Load the rule whenever name is visible - -initOrigNames :: OrigNameCache -initOrigNames = foldl extendOrigNameCache emptyModuleEnv knownKeyNames + dflags = hsc_dflags hsc_env + dump_rn_stats = dopt Opt_D_dump_rn_stats dflags + dump_if_trace = dopt Opt_D_dump_if_trace dflags \end{code} + +%************************************************************************ +%* * + Progress Messages: Module i of n +%* * +%************************************************************************ + +\begin{code} +showModuleIndex Nothing = "" +showModuleIndex (Just (i,n)) = "[" ++ padded ++ " of " ++ n_str ++ "] " + where + n_str = show n + i_str = show i + padded = replicate (length n_str - length i_str) ' ' ++ i_str +\end{code} +