{-# LANGUAGE EmptyCase #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE PatternSynonyms #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE DerivingStrategies #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeFamilyDependencies #-} {-# LANGUAGE FlexibleContexts #-} {- (c) The University of Glasgow 2006-2012 (c) The GRASP Project, Glasgow University, 1992-1998 -} -- | This module defines classes and functions for pretty-printing. It also -- exports a number of helpful debugging and other utilities such as 'trace' and 'panic'. -- -- The interface to this module is very similar to the standard Hughes-PJ pretty printing -- module, except that it exports a number of additional functions that are rarely used, -- and works over the 'SDoc' type. module GHC.Utils.Outputable ( -- * Type classes Outputable(..), OutputableBndr(..), OutputableP(..), IsOutput(..), IsLine(..), IsDoc(..), HLine, HDoc, -- * Pretty printing combinators SDoc, runSDoc, PDoc(..), docToSDoc, interppSP, interpp'SP, interpp'SP', pprQuotedList, pprWithCommas, quotedListWithOr, quotedListWithNor, pprWithBars, spaceIfSingleQuote, isEmpty, nest, ptext, int, intWithCommas, integer, word, float, double, rational, doublePrec, parens, cparen, brackets, braces, quotes, quote, doubleQuotes, angleBrackets, semi, comma, colon, dcolon, space, equals, dot, vbar, arrow, lollipop, larrow, darrow, arrowt, larrowt, arrowtt, larrowtt, lambda, lparen, rparen, lbrack, rbrack, lbrace, rbrace, underscore, blankLine, forAllLit, bullet, ($+$), cat, fcat, hang, hangNotEmpty, punctuate, ppWhen, ppUnless, ppWhenOption, ppUnlessOption, speakNth, speakN, speakNOf, plural, singular, isOrAre, doOrDoes, itsOrTheir, thisOrThese, hasOrHave, unicodeSyntax, coloured, keyword, -- * Converting 'SDoc' into strings and outputting it printSDoc, printSDocLn, bufLeftRenderSDoc, pprCode, showSDocOneLine, showSDocUnsafe, showPprUnsafe, renderWithContext, pprDebugAndThen, pprInfixVar, pprPrefixVar, pprHsChar, pprHsString, pprHsBytes, primFloatSuffix, primCharSuffix, primDoubleSuffix, primInt8Suffix, primWord8Suffix, primInt16Suffix, primWord16Suffix, primInt32Suffix, primWord32Suffix, primInt64Suffix, primWord64Suffix, primIntSuffix, primWordSuffix, pprPrimChar, pprPrimInt, pprPrimWord, pprPrimInt8, pprPrimWord8, pprPrimInt16, pprPrimWord16, pprPrimInt32, pprPrimWord32, pprPrimInt64, pprPrimWord64, pprFastFilePath, pprFilePathString, pprModuleName, -- * Controlling the style in which output is printed BindingSite(..), PprStyle(..), NamePprCtx(..), QueryQualifyName, QueryQualifyModule, QueryQualifyPackage, QueryPromotionTick, PromotedItem(..), IsEmptyOrSingleton(..), isListEmptyOrSingleton, PromotionTickContext(..), reallyAlwaysQualify, reallyAlwaysQualifyNames, alwaysQualify, alwaysQualifyNames, alwaysQualifyModules, neverQualify, neverQualifyNames, neverQualifyModules, alwaysQualifyPackages, neverQualifyPackages, alwaysPrintPromTick, QualifyName(..), queryQual, sdocOption, updSDocContext, SDocContext (..), sdocWithContext, defaultSDocContext, traceSDocContext, getPprStyle, withPprStyle, setStyleColoured, pprDeeper, pprDeeperList, pprSetDepth, codeStyle, userStyle, dumpStyle, qualName, qualModule, qualPackage, promTick, mkErrStyle, defaultErrStyle, defaultDumpStyle, mkDumpStyle, defaultUserStyle, mkUserStyle, cmdlineParserStyle, Depth(..), withUserStyle, withErrStyle, ifPprDebug, whenPprDebug, getPprDebug, bPutHDoc ) where import Language.Haskell.Syntax.Module.Name ( ModuleName(..) ) import GHC.Prelude.Basic import {-# SOURCE #-} GHC.Unit.Types ( Unit, Module, moduleName ) import {-# SOURCE #-} GHC.Types.Name.Occurrence( OccName ) import GHC.Utils.BufHandle (BufHandle, bPutChar, bPutStr, bPutFS, bPutFZS) import GHC.Data.FastString import qualified GHC.Utils.Ppr as Pretty import qualified GHC.Utils.Ppr.Colour as Col import GHC.Utils.Ppr ( Doc, Mode(..) ) import GHC.Serialized import GHC.LanguageExtensions (Extension) import GHC.Utils.GlobalVars( unsafeHasPprDebug ) import GHC.Utils.Misc (lastMaybe) import Data.ByteString (ByteString) import qualified Data.ByteString as BS import Data.Char import qualified Data.Map as M import Data.Int import qualified Data.IntMap as IM import Data.Set (Set) import qualified Data.Set as Set import qualified Data.IntSet as IntSet import Data.String import Data.Word import System.IO ( Handle ) import System.FilePath import Text.Printf import Numeric (showFFloat) import Data.Graph (SCC(..)) import Data.List (intersperse) import Data.List.NonEmpty (NonEmpty (..)) import qualified Data.List.NonEmpty as NEL import Data.Time import Data.Time.Format.ISO8601 import Data.Void import GHC.Fingerprint import GHC.Show ( showMultiLineString ) import GHC.Utils.Exception import GHC.Exts (oneShot) {- ************************************************************************ * * \subsection{The @PprStyle@ data type} * * ************************************************************************ -} data PprStyle = PprUser NamePprCtx Depth Coloured -- Pretty-print in a way that will make sense to the -- ordinary user; must be very close to Haskell -- syntax, etc. -- Assumes printing tidied code: non-system names are -- printed without uniques. | PprDump NamePprCtx -- For -ddump-foo; less verbose than in ppr-debug mode, but more than PprUser -- Does not assume tidied code: non-external names -- are printed with uniques. | PprCode -- ^ Print code; either C or assembler data Depth = AllTheWay | PartWay Int -- ^ 0 => stop | DefaultDepth -- ^ Use 'sdocDefaultDepth' field as depth data Coloured = Uncoloured | Coloured -- ----------------------------------------------------------------------------- -- Printing original names -- | When printing code that contains original names, we need to map the -- original names back to something the user understands. This is the -- purpose of the triple of functions that gets passed around -- when rendering 'SDoc'. data NamePprCtx = QueryQualify { queryQualifyName :: QueryQualifyName, queryQualifyModule :: QueryQualifyModule, queryQualifyPackage :: QueryQualifyPackage, queryPromotionTick :: QueryPromotionTick } -- | Given a `Name`'s `Module` and `OccName`, decide whether and how to qualify -- it. type QueryQualifyName = Module -> OccName -> QualifyName -- | For a given module, we need to know whether to print it with -- a package name to disambiguate it. type QueryQualifyModule = Module -> Bool -- | For a given package, we need to know whether to print it with -- the component id to disambiguate it. type QueryQualifyPackage = Unit -> Bool -- | Given a promoted data constructor, -- decide whether to print a tick to disambiguate the namespace. type QueryPromotionTick = PromotedItem -> Bool -- | Flags that affect whether a promotion tick is printed. data PromotionTickContext = PromTickCtx { ptcListTuplePuns :: !Bool, ptcPrintRedundantPromTicks :: !Bool } data PromotedItem = PromotedItemListSyntax IsEmptyOrSingleton -- '[x] | PromotedItemTupleSyntax -- '(x, y) | PromotedItemDataCon OccName -- 'MkT newtype IsEmptyOrSingleton = IsEmptyOrSingleton Bool isListEmptyOrSingleton :: [a] -> IsEmptyOrSingleton isListEmptyOrSingleton xs = IsEmptyOrSingleton $ case xs of [] -> True [_] -> True _ -> False -- See Note [Printing original names] in GHC.Types.Name.Ppr data QualifyName -- Given P:M.T = NameUnqual -- It's in scope unqualified as "T" -- OR nothing called "T" is in scope | NameQual ModuleName -- It's in scope qualified as "X.T" | NameNotInScope1 -- It's not in scope at all, but M.T is not bound -- in the current scope, so we can refer to it as "M.T" | NameNotInScope2 -- It's not in scope at all, and M.T is already bound in -- the current scope, so we must refer to it as "P:M.T" instance Outputable QualifyName where ppr NameUnqual = text "NameUnqual" ppr (NameQual _mod) = text "NameQual" -- can't print the mod without module loops :( ppr NameNotInScope1 = text "NameNotInScope1" ppr NameNotInScope2 = text "NameNotInScope2" reallyAlwaysQualifyNames :: QueryQualifyName reallyAlwaysQualifyNames _ _ = NameNotInScope2 -- | NB: This won't ever show package IDs alwaysQualifyNames :: QueryQualifyName alwaysQualifyNames m _ = NameQual (moduleName m) neverQualifyNames :: QueryQualifyName neverQualifyNames _ _ = NameUnqual alwaysQualifyModules :: QueryQualifyModule alwaysQualifyModules _ = True neverQualifyModules :: QueryQualifyModule neverQualifyModules _ = False alwaysQualifyPackages :: QueryQualifyPackage alwaysQualifyPackages _ = True neverQualifyPackages :: QueryQualifyPackage neverQualifyPackages _ = False alwaysPrintPromTick :: QueryPromotionTick alwaysPrintPromTick _ = True reallyAlwaysQualify, alwaysQualify, neverQualify :: NamePprCtx reallyAlwaysQualify = QueryQualify reallyAlwaysQualifyNames alwaysQualifyModules alwaysQualifyPackages alwaysPrintPromTick alwaysQualify = QueryQualify alwaysQualifyNames alwaysQualifyModules alwaysQualifyPackages alwaysPrintPromTick neverQualify = QueryQualify neverQualifyNames neverQualifyModules neverQualifyPackages alwaysPrintPromTick defaultUserStyle :: PprStyle defaultUserStyle = mkUserStyle neverQualify AllTheWay defaultDumpStyle :: PprStyle -- Print without qualifiers to reduce verbosity, unless -dppr-debug defaultDumpStyle = PprDump neverQualify mkDumpStyle :: NamePprCtx -> PprStyle mkDumpStyle name_ppr_ctx = PprDump name_ppr_ctx -- | Default style for error messages, when we don't know NamePprCtx -- It's a bit of a hack because it doesn't take into account what's in scope -- Only used for desugarer warnings, and typechecker errors in interface sigs defaultErrStyle :: PprStyle defaultErrStyle = mkErrStyle neverQualify -- | Style for printing error messages mkErrStyle :: NamePprCtx -> PprStyle mkErrStyle name_ppr_ctx = mkUserStyle name_ppr_ctx DefaultDepth cmdlineParserStyle :: PprStyle cmdlineParserStyle = mkUserStyle alwaysQualify AllTheWay mkUserStyle :: NamePprCtx -> Depth -> PprStyle mkUserStyle name_ppr_ctx depth = PprUser name_ppr_ctx depth Uncoloured withUserStyle :: NamePprCtx -> Depth -> SDoc -> SDoc withUserStyle name_ppr_ctx depth doc = withPprStyle (PprUser name_ppr_ctx depth Uncoloured) doc withErrStyle :: NamePprCtx -> SDoc -> SDoc withErrStyle name_ppr_ctx doc = withPprStyle (mkErrStyle name_ppr_ctx) doc setStyleColoured :: Bool -> PprStyle -> PprStyle setStyleColoured col style = case style of PprUser q d _ -> PprUser q d c _ -> style where c | col = Coloured | otherwise = Uncoloured instance Outputable PprStyle where ppr (PprUser {}) = text "user-style" ppr (PprCode {}) = text "code-style" ppr (PprDump {}) = text "dump-style" {- Orthogonal to the above printing styles are (possibly) some command-line flags that affect printing (often carried with the style). The most likely ones are variations on how much type info is shown. The following test decides whether or not we are actually generating code (either C or assembly), or generating interface files. ************************************************************************ * * \subsection{The @SDoc@ data type} * * ************************************************************************ -} -- | Represents a pretty-printable document. -- -- To display an 'SDoc', use 'printSDoc', 'printSDocLn', 'bufLeftRenderSDoc', -- or 'renderWithContext'. Avoid calling 'runSDoc' directly as it breaks the -- abstraction layer. newtype SDoc = SDoc' (SDocContext -> Doc) -- See Note [The one-shot state monad trick] in GHC.Utils.Monad {-# COMPLETE SDoc #-} pattern SDoc :: (SDocContext -> Doc) -> SDoc pattern SDoc m <- SDoc' m where SDoc m = SDoc' (oneShot m) runSDoc :: SDoc -> (SDocContext -> Doc) runSDoc (SDoc m) = m data SDocContext = SDC { sdocStyle :: !PprStyle , sdocColScheme :: !Col.Scheme , sdocLastColour :: !Col.PprColour -- ^ The most recently used colour. -- This allows nesting colours. , sdocShouldUseColor :: !Bool , sdocDefaultDepth :: !Int , sdocLineLength :: !Int , sdocCanUseUnicode :: !Bool -- ^ True if Unicode encoding is supported -- and not disabled by GHC_NO_UNICODE environment variable , sdocHexWordLiterals :: !Bool , sdocPprDebug :: !Bool , sdocPrintUnicodeSyntax :: !Bool , sdocPrintCaseAsLet :: !Bool , sdocPrintTypecheckerElaboration :: !Bool , sdocPrintAxiomIncomps :: !Bool , sdocPrintExplicitKinds :: !Bool , sdocPrintExplicitCoercions :: !Bool , sdocPrintExplicitRuntimeReps :: !Bool , sdocPrintExplicitForalls :: !Bool , sdocPrintPotentialInstances :: !Bool , sdocPrintEqualityRelations :: !Bool , sdocSuppressTicks :: !Bool , sdocSuppressTypeSignatures :: !Bool , sdocSuppressTypeApplications :: !Bool , sdocSuppressIdInfo :: !Bool , sdocSuppressCoercions :: !Bool , sdocSuppressCoercionTypes :: !Bool , sdocSuppressUnfoldings :: !Bool , sdocSuppressVarKinds :: !Bool , sdocSuppressUniques :: !Bool , sdocSuppressModulePrefixes :: !Bool , sdocSuppressStgExts :: !Bool , sdocSuppressStgReps :: !Bool , sdocErrorSpans :: !Bool , sdocStarIsType :: !Bool , sdocLinearTypes :: !Bool , sdocListTuplePuns :: !Bool , sdocPrintTypeAbbreviations :: !Bool , sdocUnitIdForUser :: !(FastString -> SDoc) -- ^ Used to map UnitIds to more friendly "package-version:component" -- strings while pretty-printing. -- -- Use `GHC.Unit.State.pprWithUnitState` to set it. Users should never -- have to set it to pretty-print SDocs emitted by GHC, otherwise it's a -- bug. It's an internal field used to thread the UnitState so that the -- Outputable instance of UnitId can use it. -- -- See Note [Pretty-printing UnitId] in "GHC.Unit" for more details. -- -- Note that we use `FastString` instead of `UnitId` to avoid boring -- module inter-dependency issues. } instance IsString SDoc where fromString = text -- The lazy programmer's friend. instance Outputable SDoc where ppr = id -- | Default pretty-printing options defaultSDocContext :: SDocContext defaultSDocContext = SDC { sdocStyle = defaultDumpStyle , sdocColScheme = Col.defaultScheme , sdocLastColour = Col.colReset , sdocShouldUseColor = False , sdocDefaultDepth = 5 , sdocLineLength = 100 , sdocCanUseUnicode = False , sdocHexWordLiterals = False , sdocPprDebug = False , sdocPrintUnicodeSyntax = False , sdocPrintCaseAsLet = False , sdocPrintTypecheckerElaboration = False , sdocPrintAxiomIncomps = False , sdocPrintExplicitKinds = False , sdocPrintExplicitCoercions = False , sdocPrintExplicitRuntimeReps = False , sdocPrintExplicitForalls = False , sdocPrintPotentialInstances = False , sdocPrintEqualityRelations = False , sdocSuppressTicks = False , sdocSuppressTypeSignatures = False , sdocSuppressTypeApplications = False , sdocSuppressIdInfo = False , sdocSuppressCoercions = False , sdocSuppressCoercionTypes = False , sdocSuppressUnfoldings = False , sdocSuppressVarKinds = False , sdocSuppressUniques = False , sdocSuppressModulePrefixes = False , sdocSuppressStgExts = False , sdocSuppressStgReps = True , sdocErrorSpans = False , sdocStarIsType = False , sdocLinearTypes = False , sdocListTuplePuns = True , sdocPrintTypeAbbreviations = True , sdocUnitIdForUser = ftext } traceSDocContext :: SDocContext -- Used for pprTrace, when we want to see lots of info traceSDocContext = defaultSDocContext { sdocPprDebug = unsafeHasPprDebug , sdocPrintTypecheckerElaboration = True , sdocPrintExplicitKinds = True , sdocPrintExplicitCoercions = True , sdocPrintExplicitRuntimeReps = True , sdocPrintExplicitForalls = True , sdocPrintEqualityRelations = True } withPprStyle :: PprStyle -> SDoc -> SDoc {-# INLINE CONLIKE withPprStyle #-} withPprStyle sty d = SDoc $ \ctxt -> runSDoc d ctxt{sdocStyle=sty} pprDeeper :: SDoc -> SDoc pprDeeper d = SDoc $ \ctx -> case sdocStyle ctx of PprUser q depth c -> let deeper 0 = Pretty.text "..." deeper n = runSDoc d ctx{sdocStyle = PprUser q (PartWay (n-1)) c} in case depth of DefaultDepth -> deeper (sdocDefaultDepth ctx) PartWay n -> deeper n AllTheWay -> runSDoc d ctx _ -> runSDoc d ctx -- | Truncate a list that is longer than the current depth. pprDeeperList :: ([SDoc] -> SDoc) -> [SDoc] -> SDoc pprDeeperList f ds | null ds = f [] | otherwise = SDoc work where work ctx@SDC{sdocStyle=PprUser q depth c} | DefaultDepth <- depth = work (ctx { sdocStyle = PprUser q (PartWay (sdocDefaultDepth ctx)) c }) | PartWay 0 <- depth = Pretty.text "..." | PartWay n <- depth = let go _ [] = [] go i (d:ds) | i >= n = [text "...."] | otherwise = d : go (i+1) ds in runSDoc (f (go 0 ds)) ctx{sdocStyle = PprUser q (PartWay (n-1)) c} work other_ctx = runSDoc (f ds) other_ctx pprSetDepth :: Depth -> SDoc -> SDoc pprSetDepth depth doc = SDoc $ \ctx -> case ctx of SDC{sdocStyle=PprUser q _ c} -> runSDoc doc ctx{sdocStyle = PprUser q depth c} _ -> runSDoc doc ctx getPprStyle :: (PprStyle -> SDoc) -> SDoc {-# INLINE CONLIKE getPprStyle #-} getPprStyle df = SDoc $ \ctx -> runSDoc (df (sdocStyle ctx)) ctx sdocWithContext :: (SDocContext -> SDoc) -> SDoc {-# INLINE CONLIKE sdocWithContext #-} sdocWithContext f = SDoc $ \ctx -> runSDoc (f ctx) ctx sdocOption :: (SDocContext -> a) -> (a -> SDoc) -> SDoc {-# INLINE CONLIKE sdocOption #-} sdocOption f g = sdocWithContext (g . f) updSDocContext :: (SDocContext -> SDocContext) -> SDoc -> SDoc {-# INLINE CONLIKE updSDocContext #-} updSDocContext upd doc = SDoc $ \ctx -> runSDoc doc (upd ctx) qualName :: PprStyle -> QueryQualifyName qualName (PprUser q _ _) mod occ = queryQualifyName q mod occ qualName (PprDump q) mod occ = queryQualifyName q mod occ qualName _other mod _ = NameQual (moduleName mod) qualModule :: PprStyle -> QueryQualifyModule qualModule (PprUser q _ _) m = queryQualifyModule q m qualModule (PprDump q) m = queryQualifyModule q m qualModule _other _m = True qualPackage :: PprStyle -> QueryQualifyPackage qualPackage (PprUser q _ _) m = queryQualifyPackage q m qualPackage (PprDump q) m = queryQualifyPackage q m qualPackage _other _m = True promTick :: PprStyle -> QueryPromotionTick promTick (PprUser q _ _) occ = queryPromotionTick q occ promTick (PprDump q) occ = queryPromotionTick q occ promTick _ _ = True queryQual :: PprStyle -> NamePprCtx queryQual s = QueryQualify (qualName s) (qualModule s) (qualPackage s) (promTick s) codeStyle :: PprStyle -> Bool codeStyle PprCode = True codeStyle _ = False dumpStyle :: PprStyle -> Bool dumpStyle (PprDump {}) = True dumpStyle _other = False userStyle :: PprStyle -> Bool userStyle (PprUser {}) = True userStyle _other = False -- | Indicate if -dppr-debug mode is enabled getPprDebug :: IsOutput doc => (Bool -> doc) -> doc {-# INLINE CONLIKE getPprDebug #-} getPprDebug d = docWithContext $ \ctx -> d (sdocPprDebug ctx) -- | Says what to do with and without -dppr-debug ifPprDebug :: IsOutput doc => doc -> doc -> doc {-# INLINE CONLIKE ifPprDebug #-} ifPprDebug yes no = getPprDebug $ \dbg -> if dbg then yes else no -- | Says what to do with -dppr-debug; without, return empty whenPprDebug :: IsOutput doc => doc -> doc -- Empty for non-debug style {-# INLINE CONLIKE whenPprDebug #-} whenPprDebug d = ifPprDebug d empty -- | The analog of 'Pretty.printDoc_' for 'SDoc', which tries to make sure the -- terminal doesn't get screwed up by the ANSI color codes if an exception -- is thrown during pretty-printing. printSDoc :: SDocContext -> Mode -> Handle -> SDoc -> IO () printSDoc ctx mode handle doc = Pretty.printDoc_ mode cols handle (runSDoc doc ctx) `finally` Pretty.printDoc_ mode cols handle (runSDoc (coloured Col.colReset empty) ctx) where cols = sdocLineLength ctx -- | Like 'printSDoc' but appends an extra newline. printSDocLn :: SDocContext -> Mode -> Handle -> SDoc -> IO () printSDocLn ctx mode handle doc = printSDoc ctx mode handle (doc $$ text "") -- | An efficient variant of 'printSDoc' specialized for 'LeftMode' that -- outputs to a 'BufHandle'. bufLeftRenderSDoc :: SDocContext -> BufHandle -> SDoc -> IO () bufLeftRenderSDoc ctx bufHandle doc = Pretty.bufLeftRender bufHandle (runSDoc doc ctx) pprCode :: SDoc -> SDoc {-# INLINE CONLIKE pprCode #-} pprCode d = withPprStyle PprCode d renderWithContext :: SDocContext -> SDoc -> String renderWithContext ctx sdoc = let s = Pretty.style{ Pretty.mode = PageMode False, Pretty.lineLength = sdocLineLength ctx } in Pretty.renderStyle s $ runSDoc sdoc ctx -- This shows an SDoc, but on one line only. It's cheaper than a full -- showSDoc, designed for when we're getting results like "Foo.bar" -- and "foo{uniq strictness}" so we don't want fancy layout anyway. showSDocOneLine :: SDocContext -> SDoc -> String showSDocOneLine ctx d = let s = Pretty.style{ Pretty.mode = OneLineMode, Pretty.lineLength = sdocLineLength ctx } in Pretty.renderStyle s $ runSDoc d ctx showSDocUnsafe :: SDoc -> String showSDocUnsafe sdoc = renderWithContext defaultSDocContext sdoc showPprUnsafe :: Outputable a => a -> String showPprUnsafe a = renderWithContext defaultSDocContext (ppr a) pprDebugAndThen :: SDocContext -> (String -> a) -> SDoc -> SDoc -> a pprDebugAndThen ctx cont heading pretty_msg = cont (renderWithContext ctx doc) where doc = withPprStyle defaultDumpStyle (sep [heading, nest 2 pretty_msg]) isEmpty :: SDocContext -> SDoc -> Bool isEmpty ctx sdoc = Pretty.isEmpty $ runSDoc sdoc (ctx {sdocPprDebug = True}) docToSDoc :: Doc -> SDoc docToSDoc d = SDoc (\_ -> d) ptext :: PtrString -> SDoc int :: IsLine doc => Int -> doc integer :: IsLine doc => Integer -> doc word :: Integer -> SDoc float :: IsLine doc => Float -> doc double :: IsLine doc => Double -> doc rational :: Rational -> SDoc {-# INLINE CONLIKE ptext #-} ptext s = docToSDoc $ Pretty.ptext s {-# INLINE CONLIKE int #-} int n = text $ show n {-# INLINE CONLIKE integer #-} integer n = text $ show n {-# INLINE CONLIKE float #-} float n = text $ show n {-# INLINE CONLIKE double #-} double n = text $ show n {-# INLINE CONLIKE rational #-} rational n = text $ show n -- See Note [Print Hexadecimal Literals] in GHC.Utils.Ppr {-# INLINE CONLIKE word #-} word n = sdocOption sdocHexWordLiterals $ \case True -> docToSDoc $ Pretty.hex n False -> docToSDoc $ Pretty.integer n -- | @doublePrec p n@ shows a floating point number @n@ with @p@ -- digits of precision after the decimal point. doublePrec :: Int -> Double -> SDoc doublePrec p n = text (showFFloat (Just p) n "") quotes, quote :: SDoc -> SDoc parens, brackets, braces, doubleQuotes, angleBrackets :: IsLine doc => doc -> doc {-# INLINE CONLIKE parens #-} parens d = char '(' <> d <> char ')' {-# INLINE CONLIKE braces #-} braces d = char '{' <> d <> char '}' {-# INLINE CONLIKE brackets #-} brackets d = char '[' <> d <> char ']' {-# INLINE CONLIKE quote #-} quote d = SDoc $ Pretty.quote . runSDoc d {-# INLINE CONLIKE doubleQuotes #-} doubleQuotes d = char '"' <> d <> char '"' {-# INLINE CONLIKE angleBrackets #-} angleBrackets d = char '<' <> d <> char '>' cparen :: Bool -> SDoc -> SDoc {-# INLINE CONLIKE cparen #-} cparen b d = SDoc $ Pretty.maybeParens b . runSDoc d -- 'quotes' encloses something in single quotes... -- but it omits them if the thing begins or ends in a single quote -- so that we don't get `foo''. Instead we just have foo'. quotes d = sdocOption sdocCanUseUnicode $ \case True -> char '‘' <> d <> char '’' False -> SDoc $ \sty -> let pp_d = runSDoc d sty str = show pp_d in case str of [] -> Pretty.quotes pp_d '\'' : _ -> pp_d _ | Just '\'' <- lastMaybe str -> pp_d | otherwise -> Pretty.quotes pp_d blankLine, dcolon, arrow, lollipop, larrow, darrow, arrowt, larrowt, arrowtt, larrowtt, lambda :: SDoc blankLine = docToSDoc Pretty.emptyText dcolon = unicodeSyntax (char '∷') (text "::") arrow = unicodeSyntax (char '→') (text "->") lollipop = unicodeSyntax (char '⊸') (text "%1 ->") larrow = unicodeSyntax (char '←') (text "<-") darrow = unicodeSyntax (char '⇒') (text "=>") arrowt = unicodeSyntax (char '⤚') (text ">-") larrowt = unicodeSyntax (char '⤙') (text "-<") arrowtt = unicodeSyntax (char '⤜') (text ">>-") larrowtt = unicodeSyntax (char '⤛') (text "-<<") lambda = unicodeSyntax (char 'λ') (char '\\') semi, comma, colon, equals, space, underscore, dot, vbar :: IsLine doc => doc lparen, rparen, lbrack, rbrack, lbrace, rbrace :: IsLine doc => doc semi = char ';' comma = char ',' colon = char ':' equals = char '=' space = char ' ' underscore = char '_' dot = char '.' vbar = char '|' lparen = char '(' rparen = char ')' lbrack = char '[' rbrack = char ']' lbrace = char '{' rbrace = char '}' forAllLit :: SDoc forAllLit = unicodeSyntax (char '∀') (text "forall") bullet :: SDoc bullet = unicode (char '•') (char '*') unicodeSyntax :: SDoc -> SDoc -> SDoc unicodeSyntax unicode plain = sdocOption sdocCanUseUnicode $ \can_use_unicode -> sdocOption sdocPrintUnicodeSyntax $ \print_unicode_syntax -> if can_use_unicode && print_unicode_syntax then unicode else plain unicode :: SDoc -> SDoc -> SDoc unicode unicode plain = sdocOption sdocCanUseUnicode $ \case True -> unicode False -> plain nest :: Int -> SDoc -> SDoc -- ^ Indent 'SDoc' some specified amount ($+$) :: SDoc -> SDoc -> SDoc -- ^ Join two 'SDoc' together vertically {-# INLINE CONLIKE nest #-} nest n d = SDoc $ Pretty.nest n . runSDoc d {-# INLINE CONLIKE ($+$) #-} ($+$) d1 d2 = SDoc $ \ctx -> (Pretty.$+$) (runSDoc d1 ctx) (runSDoc d2 ctx) cat :: [SDoc] -> SDoc -- ^ A paragraph-fill combinator. It's much like sep, only it -- keeps fitting things on one line until it can't fit any more. fcat :: [SDoc] -> SDoc -- ^ This behaves like 'fsep', but it uses '<>' for horizontal composition rather than '<+>' -- Inline all those wrappers to help ensure we create lists of Doc, not of SDoc -- later applied to the same SDocContext. It helps the worker/wrapper -- transformation extracting only the required fields from the SDocContext. {-# INLINE CONLIKE cat #-} cat ds = SDoc $ \ctx -> Pretty.cat [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE fcat #-} fcat ds = SDoc $ \ctx -> Pretty.fcat [runSDoc d ctx | d <- ds] hang :: SDoc -- ^ The header -> Int -- ^ Amount to indent the hung body -> SDoc -- ^ The hung body, indented and placed below the header -> SDoc {-# INLINE CONLIKE hang #-} hang d1 n d2 = SDoc $ \sty -> Pretty.hang (runSDoc d1 sty) n (runSDoc d2 sty) -- | This behaves like 'hang', but does not indent the second document -- when the header is empty. hangNotEmpty :: SDoc -> Int -> SDoc -> SDoc {-# INLINE CONLIKE hangNotEmpty #-} hangNotEmpty d1 n d2 = SDoc $ \ctx -> Pretty.hangNotEmpty (runSDoc d1 ctx) n (runSDoc d2 ctx) punctuate :: IsLine doc => doc -- ^ The punctuation -> [doc] -- ^ The list that will have punctuation added between every adjacent pair of elements -> [doc] -- ^ Punctuated list punctuate _ [] = [] punctuate p (d:ds) = go d ds where go d [] = [d] go d (e:es) = (d <> p) : go e es ppWhen, ppUnless :: IsOutput doc => Bool -> doc -> doc {-# INLINE CONLIKE ppWhen #-} ppWhen True doc = doc ppWhen False _ = empty {-# INLINE CONLIKE ppUnless #-} ppUnless True _ = empty ppUnless False doc = doc {-# INLINE CONLIKE ppWhenOption #-} ppWhenOption :: (SDocContext -> Bool) -> SDoc -> SDoc ppWhenOption f doc = sdocOption f $ \case True -> doc False -> empty {-# INLINE CONLIKE ppUnlessOption #-} ppUnlessOption :: IsLine doc => (SDocContext -> Bool) -> doc -> doc ppUnlessOption f doc = docWithContext $ \ctx -> if f ctx then empty else doc -- | Apply the given colour\/style for the argument. -- -- Only takes effect if colours are enabled. coloured :: Col.PprColour -> SDoc -> SDoc coloured col sdoc = sdocOption sdocShouldUseColor $ \case True -> SDoc $ \case ctx@SDC{ sdocLastColour = lastCol, sdocStyle = PprUser _ _ Coloured } -> let ctx' = ctx{ sdocLastColour = lastCol `mappend` col } in Pretty.zeroWidthText (Col.renderColour col) Pretty.<> runSDoc sdoc ctx' Pretty.<> Pretty.zeroWidthText (Col.renderColourAfresh lastCol) ctx -> runSDoc sdoc ctx False -> sdoc keyword :: SDoc -> SDoc keyword = coloured Col.colBold ----------------------------------------------------------------------- -- The @Outputable@ class ----------------------------------------------------------------------- -- | Class designating that some type has an 'SDoc' representation class Outputable a where ppr :: a -> SDoc -- There's no Outputable for Char; it's too easy to use Outputable -- on String and have ppr "hello" rendered as "h,e,l,l,o". instance Outputable Bool where ppr True = text "True" ppr False = text "False" instance Outputable Ordering where ppr LT = text "LT" ppr EQ = text "EQ" ppr GT = text "GT" instance Outputable Int32 where ppr n = integer $ fromIntegral n instance Outputable Int64 where ppr n = integer $ fromIntegral n instance Outputable Int where ppr n = int n instance Outputable Integer where ppr n = integer n instance Outputable Word16 where ppr n = integer $ fromIntegral n instance Outputable Word32 where ppr n = integer $ fromIntegral n instance Outputable Word64 where ppr n = integer $ fromIntegral n instance Outputable Word where ppr n = integer $ fromIntegral n instance Outputable Float where ppr f = float f instance Outputable Double where ppr f = double f instance Outputable () where ppr _ = text "()" instance Outputable UTCTime where ppr = text . formatShow iso8601Format instance (Outputable a) => Outputable [a] where ppr xs = brackets (pprWithCommas ppr xs) instance (Outputable a) => Outputable (NonEmpty a) where ppr = ppr . NEL.toList instance (Outputable a) => Outputable (Set a) where ppr s = braces (pprWithCommas ppr (Set.toList s)) instance Outputable IntSet.IntSet where ppr s = braces (pprWithCommas ppr (IntSet.toList s)) instance (Outputable a, Outputable b) => Outputable (a, b) where ppr (x,y) = parens (sep [ppr x <> comma, ppr y]) instance Outputable a => Outputable (Maybe a) where ppr Nothing = text "Nothing" ppr (Just x) = text "Just" <+> ppr x instance (Outputable a, Outputable b) => Outputable (Either a b) where ppr (Left x) = text "Left" <+> ppr x ppr (Right y) = text "Right" <+> ppr y -- ToDo: may not be used instance (Outputable a, Outputable b, Outputable c) => Outputable (a, b, c) where ppr (x,y,z) = parens (sep [ppr x <> comma, ppr y <> comma, ppr z ]) instance (Outputable a, Outputable b, Outputable c, Outputable d) => Outputable (a, b, c, d) where ppr (a,b,c,d) = parens (sep [ppr a <> comma, ppr b <> comma, ppr c <> comma, ppr d]) instance (Outputable a, Outputable b, Outputable c, Outputable d, Outputable e) => Outputable (a, b, c, d, e) where ppr (a,b,c,d,e) = parens (sep [ppr a <> comma, ppr b <> comma, ppr c <> comma, ppr d <> comma, ppr e]) instance (Outputable a, Outputable b, Outputable c, Outputable d, Outputable e, Outputable f) => Outputable (a, b, c, d, e, f) where ppr (a,b,c,d,e,f) = parens (sep [ppr a <> comma, ppr b <> comma, ppr c <> comma, ppr d <> comma, ppr e <> comma, ppr f]) instance (Outputable a, Outputable b, Outputable c, Outputable d, Outputable e, Outputable f, Outputable g) => Outputable (a, b, c, d, e, f, g) where ppr (a,b,c,d,e,f,g) = parens (sep [ppr a <> comma, ppr b <> comma, ppr c <> comma, ppr d <> comma, ppr e <> comma, ppr f <> comma, ppr g]) instance Outputable FastString where ppr fs = ftext fs -- Prints an unadorned string, -- no double quotes or anything deriving newtype instance Outputable NonDetFastString deriving newtype instance Outputable LexicalFastString instance (Outputable key, Outputable elt) => Outputable (M.Map key elt) where ppr m = ppr (M.toList m) instance (Outputable elt) => Outputable (IM.IntMap elt) where ppr m = ppr (IM.toList m) instance Outputable Fingerprint where ppr (Fingerprint w1 w2) = text (printf "%016x%016x" w1 w2) instance Outputable a => Outputable (SCC a) where ppr (AcyclicSCC v) = text "NONREC" $$ (nest 3 (ppr v)) ppr (CyclicSCC vs) = text "REC" $$ (nest 3 (vcat (map ppr vs))) instance Outputable Serialized where ppr (Serialized the_type bytes) = int (length bytes) <+> text "of type" <+> text (show the_type) instance Outputable Extension where ppr = text . show instance Outputable ModuleName where ppr = pprModuleName pprModuleName :: IsLine doc => ModuleName -> doc pprModuleName (ModuleName nm) = docWithContext $ \ctx -> if codeStyle (sdocStyle ctx) then ztext (zEncodeFS nm) else ftext nm {-# SPECIALIZE pprModuleName :: ModuleName -> SDoc #-} {-# SPECIALIZE pprModuleName :: ModuleName -> HLine #-} -- see Note [SPECIALIZE to HDoc] ----------------------------------------------------------------------- -- The @OutputableP@ class ----------------------------------------------------------------------- -- Note [The OutputableP class] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- -- SDoc has become the common type to -- * display messages in the terminal -- * dump outputs (Cmm, Asm, C, etc.) -- * return messages to ghc-api clients -- -- SDoc is a kind of state Monad: SDoc ~ State SDocContext Doc -- I.e. to render a SDoc, a SDocContext must be provided. -- -- SDocContext contains legit rendering options (e.g., line length, color and -- unicode settings). Sadly SDocContext ended up also being used to thread -- values that were considered bothersome to thread otherwise: -- * current HomeModule: to decide if module names must be printed qualified -- * current UnitState: to print unit-ids as "packagename-version:component" -- * target platform: to render labels, instructions, etc. -- * selected backend: to display CLabel as C labels or Asm labels -- -- In fact the whole compiler session state that is DynFlags was passed in -- SDocContext and these values were retrieved from it. -- -- The Outputable class makes SDoc creation easy for many values by providing -- the ppr method: -- -- class Outputable a where -- ppr :: a -> SDoc -- -- Almost every type is Outputable in the compiler and it seems great because it -- is similar to the Show class. But it's a fallacious simplicity because `SDoc` -- needs a `SDocContext` to be transformed into a renderable `Doc`: who is going -- to provide the SDocContext with the correct values in it? -- -- E.g. if a SDoc is returned in an exception, how could we know the home -- module at the time it was thrown? -- -- A workaround is to pass dummy values (no home module, empty UnitState) at SDoc -- rendering time and to hope that the code that produced the SDoc has updated -- the SDocContext with meaningful values (e.g. using withPprStyle or -- pprWithUnitState). If the context isn't correctly updated, a dummy value is -- used and the printed result isn't what we expected. Note that the compiler -- doesn't help us finding spots where we need to update the SDocContext. -- -- In some cases we can't pass a dummy value because we can't create one. For -- example, how can we create a dummy Platform value? In the old days, GHC only -- supported a single Platform set when it was built, so we could use it without -- any risk of mistake. But now GHC starts supporting several Platform in the -- same session so it becomes an issue. We could be tempted to use the -- workaround described above by using "undefined" as a dummy Platform value. -- However in this case, if we forget to update it we will get a runtime -- error/crash. We could use "Maybe Platform" and die with a better error -- message at places where we really really need to know if we are on Windows or -- not, or if we use 32- or 64-bit. Still the compiler would not help us in -- finding spots where to update the context with a valid Platform. -- -- So finally here comes the OutputableP class: -- -- class OutputableP env a where -- pdoc :: env -> a -> SDoc -- -- OutputableP forces us to thread an environment necessary to print a value. -- For now we only use it to thread a Platform environment, so we have several -- "Outputable Platform XYZ" instances. In the future we could imagine using a -- Has class to retrieve a value from a generic environment to make the code -- more composable. E.g.: -- -- instance Has Platform env => OutputableP env XYZ where -- pdoc env a = ... (getter env :: Platform) -- -- A drawback of this approach over Outputable is that we have to thread an -- environment explicitly to use "pdoc" and it's more cumbersome. But it's the -- price to pay to have some help from the compiler to ensure that we... thread -- an environment down to the places where we need it, i.e. where SDoc are -- created (not rendered). On the other hand, it makes life easier for SDoc -- renderers as they only have to deal with pretty-printing related options in -- SDocContext. -- -- TODO: -- -- 1) we could use OutputableP to thread a UnitState and replace the Outputable -- instance of UnitId with: -- -- instance OutputableP UnitState UnitId where ... -- -- This would allow the removal of the `sdocUnitIdForUser` field. -- -- Be warned: I've tried to do it, but there are A LOT of other Outputable -- instances depending on UnitId's one. In particular: -- UnitId <- Unit <- Module <- Name <- Var <- Core.{Type,Expr} <- ... -- -- 2) Use it to pass the HomeModule (but I fear it will be as difficult as for -- UnitId). -- -- -- | Outputable class with an additional environment value -- -- See Note [The OutputableP class] class OutputableP env a where pdoc :: env -> a -> SDoc -- | Wrapper for types having a Outputable instance when an OutputableP instance -- is required. newtype PDoc a = PDoc a instance Outputable a => OutputableP env (PDoc a) where pdoc _ (PDoc a) = ppr a instance OutputableP env a => OutputableP env [a] where pdoc env xs = ppr (fmap (pdoc env) xs) instance OutputableP env a => OutputableP env (Maybe a) where pdoc env xs = ppr (fmap (pdoc env) xs) instance (OutputableP env a, OutputableP env b) => OutputableP env (a, b) where pdoc env (a,b) = ppr (pdoc env a, pdoc env b) instance (OutputableP env a, OutputableP env b, OutputableP env c) => OutputableP env (a, b, c) where pdoc env (a,b,c) = ppr (pdoc env a, pdoc env b, pdoc env c) instance (OutputableP env key, OutputableP env elt) => OutputableP env (M.Map key elt) where pdoc env m = ppr $ fmap (\(x,y) -> (pdoc env x, pdoc env y)) $ M.toList m instance OutputableP env a => OutputableP env (SCC a) where pdoc env scc = ppr (fmap (pdoc env) scc) instance OutputableP env SDoc where pdoc _ x = x instance (OutputableP env a) => OutputableP env (Set a) where pdoc env s = braces (fsep (punctuate comma (map (pdoc env) (Set.toList s)))) instance OutputableP env Void where pdoc _ = \ case {- ************************************************************************ * * \subsection{The @OutputableBndr@ class} * * ************************************************************************ -} -- | 'BindingSite' is used to tell the thing that prints binder what -- language construct is binding the identifier. This can be used -- to decide how much info to print. -- Also see Note [Binding-site specific printing] in "GHC.Core.Ppr" data BindingSite = LambdaBind -- ^ The x in (\x. e) | CaseBind -- ^ The x in case scrut of x { (y,z) -> ... } | CasePatBind -- ^ The y,z in case scrut of x { (y,z) -> ... } | LetBind -- ^ The x in (let x = rhs in e) deriving Eq -- | When we print a binder, we often want to print its type too. -- The @OutputableBndr@ class encapsulates this idea. class Outputable a => OutputableBndr a where pprBndr :: BindingSite -> a -> SDoc pprBndr _b x = ppr x pprPrefixOcc, pprInfixOcc :: a -> SDoc -- Print an occurrence of the name, suitable either in the -- prefix position of an application, thus (f a b) or ((+) x) -- or infix position, thus (a `f` b) or (x + y) bndrIsJoin_maybe :: a -> Maybe Int bndrIsJoin_maybe _ = Nothing -- When pretty-printing we sometimes want to find -- whether the binder is a join point. You might think -- we could have a function of type (a->Var), but Var -- isn't available yet, alas {- ************************************************************************ * * \subsection{Random printing helpers} * * ************************************************************************ -} -- We have 31-bit Chars and will simply use Show instances of Char and String. -- | Special combinator for showing character literals. pprHsChar :: Char -> SDoc pprHsChar c | c > '\x10ffff' = char '\\' <> text (show (fromIntegral (ord c) :: Word32)) | otherwise = text (show c) -- | Special combinator for showing string literals. pprHsString :: FastString -> SDoc pprHsString fs = vcat (map text (showMultiLineString (unpackFS fs))) -- | Special combinator for showing bytestring literals. pprHsBytes :: ByteString -> SDoc pprHsBytes bs = let escaped = concatMap escape $ BS.unpack bs in vcat (map text (showMultiLineString escaped)) <> char '#' where escape :: Word8 -> String escape w = let c = chr (fromIntegral w) in if isAscii c then [c] else '\\' : show w -- Postfix modifiers for unboxed literals. -- See Note [Printing of literals in Core] in "GHC.Types.Literal". primCharSuffix, primFloatSuffix, primDoubleSuffix, primIntSuffix, primWordSuffix, primInt8Suffix, primWord8Suffix, primInt16Suffix, primWord16Suffix, primInt32Suffix, primWord32Suffix, primInt64Suffix, primWord64Suffix :: SDoc primCharSuffix = char '#' primFloatSuffix = char '#' primIntSuffix = char '#' primDoubleSuffix = text "##" primWordSuffix = text "##" primInt8Suffix = text "#Int8" primWord8Suffix = text "#Word8" primInt16Suffix = text "#Int16" primWord16Suffix = text "#Word16" primInt32Suffix = text "#Int32" primWord32Suffix = text "#Word32" primInt64Suffix = text "#Int64" primWord64Suffix = text "#Word64" -- | Special combinator for showing unboxed literals. pprPrimChar :: Char -> SDoc pprPrimInt, pprPrimWord, pprPrimInt8, pprPrimWord8, pprPrimInt16, pprPrimWord16, pprPrimInt32, pprPrimWord32, pprPrimInt64, pprPrimWord64 :: Integer -> SDoc pprPrimChar c = pprHsChar c <> primCharSuffix pprPrimInt i = integer i <> primIntSuffix pprPrimWord w = word w <> primWordSuffix pprPrimInt8 i = integer i <> primInt8Suffix pprPrimInt16 i = integer i <> primInt16Suffix pprPrimInt32 i = integer i <> primInt32Suffix pprPrimInt64 i = integer i <> primInt64Suffix pprPrimWord8 w = word w <> primWord8Suffix pprPrimWord16 w = word w <> primWord16Suffix pprPrimWord32 w = word w <> primWord32Suffix pprPrimWord64 w = word w <> primWord64Suffix --------------------- -- Put a name in parens if it's an operator pprPrefixVar :: Bool -> SDoc -> SDoc pprPrefixVar is_operator pp_v | is_operator = parens pp_v | otherwise = pp_v -- Put a name in backquotes if it's not an operator pprInfixVar :: Bool -> SDoc -> SDoc pprInfixVar is_operator pp_v | is_operator = pp_v | otherwise = char '`' <> pp_v <> char '`' --------------------- pprFastFilePath :: FastString -> SDoc pprFastFilePath path = text $ normalise $ unpackFS path -- | Normalise, escape and render a string representing a path -- -- e.g. "c:\\whatever" pprFilePathString :: IsLine doc => FilePath -> doc pprFilePathString path = doubleQuotes $ text (escape (normalise path)) where escape [] = [] escape ('\\':xs) = '\\':'\\':escape xs escape (x:xs) = x:escape xs {-# SPECIALIZE pprFilePathString :: FilePath -> SDoc #-} {-# SPECIALIZE pprFilePathString :: FilePath -> HLine #-} -- see Note [SPECIALIZE to HDoc] {- ************************************************************************ * * \subsection{Other helper functions} * * ************************************************************************ -} pprWithCommas :: (a -> SDoc) -- ^ The pretty printing function to use -> [a] -- ^ The things to be pretty printed -> SDoc -- ^ 'SDoc' where the things have been pretty printed, -- comma-separated and finally packed into a paragraph. pprWithCommas pp xs = fsep (punctuate comma (map pp xs)) pprWithBars :: (a -> SDoc) -- ^ The pretty printing function to use -> [a] -- ^ The things to be pretty printed -> SDoc -- ^ 'SDoc' where the things have been pretty printed, -- bar-separated and finally packed into a paragraph. pprWithBars pp xs = fsep (intersperse vbar (map pp xs)) -- Prefix the document with a space if it starts with a single quote. -- See Note [Printing promoted type constructors] in GHC.Iface.Type spaceIfSingleQuote :: SDoc -> SDoc spaceIfSingleQuote (SDoc m) = SDoc $ \ctx -> let (mHead, d) = Pretty.docHead (m ctx) in if mHead == Just '\'' then Pretty.space Pretty.<> d else d -- | Returns the separated concatenation of the pretty printed things. interppSP :: Outputable a => [a] -> SDoc interppSP xs = sep (map ppr xs) -- | Returns the comma-separated concatenation of the pretty printed things. interpp'SP :: Outputable a => [a] -> SDoc interpp'SP xs = interpp'SP' ppr xs interpp'SP' :: (a -> SDoc) -> [a] -> SDoc interpp'SP' f xs = sep (punctuate comma (map f xs)) -- | Returns the comma-separated concatenation of the quoted pretty printed things. -- -- > [x,y,z] ==> `x', `y', `z' pprQuotedList :: Outputable a => [a] -> SDoc pprQuotedList = quotedList . map ppr quotedList :: [SDoc] -> SDoc quotedList xs = fsep (punctuate comma (map quotes xs)) quotedListWithOr :: [SDoc] -> SDoc -- [x,y,z] ==> `x', `y' or `z' quotedListWithOr xs@(_:_:_) = quotedList (init xs) <+> text "or" <+> quotes (last xs) quotedListWithOr xs = quotedList xs quotedListWithNor :: [SDoc] -> SDoc -- [x,y,z] ==> `x', `y' nor `z' quotedListWithNor xs@(_:_:_) = quotedList (init xs) <+> text "nor" <+> quotes (last xs) quotedListWithNor xs = quotedList xs {- ************************************************************************ * * \subsection{Printing numbers verbally} * * ************************************************************************ -} intWithCommas :: Integral a => a -> SDoc -- Prints a big integer with commas, eg 345,821 intWithCommas n | n < 0 = char '-' <> intWithCommas (-n) | q == 0 = int (fromIntegral r) | otherwise = intWithCommas q <> comma <> zeroes <> int (fromIntegral r) where (q,r) = n `quotRem` 1000 zeroes | r >= 100 = empty | r >= 10 = char '0' | otherwise = text "00" -- | Converts an integer to a verbal index: -- -- > speakNth 1 = text "first" -- > speakNth 5 = text "fifth" -- > speakNth 21 = text "21st" speakNth :: Int -> SDoc speakNth 1 = text "first" speakNth 2 = text "second" speakNth 3 = text "third" speakNth 4 = text "fourth" speakNth 5 = text "fifth" speakNth 6 = text "sixth" speakNth n = hcat [ int n, text suffix ] where suffix | n <= 20 = "th" -- 11,12,13 are non-std | last_dig == 1 = "st" | last_dig == 2 = "nd" | last_dig == 3 = "rd" | otherwise = "th" last_dig = n `rem` 10 -- | Converts an integer to a verbal multiplicity: -- -- > speakN 0 = text "none" -- > speakN 5 = text "five" -- > speakN 10 = text "10" speakN :: Int -> SDoc speakN 0 = text "none" -- E.g. "they have none" speakN 1 = text "one" -- E.g. "they have one" speakN 2 = text "two" speakN 3 = text "three" speakN 4 = text "four" speakN 5 = text "five" speakN 6 = text "six" speakN n = int n -- | Converts an integer and object description to a statement about the -- multiplicity of those objects: -- -- > speakNOf 0 (text "melon") = text "no melons" -- > speakNOf 1 (text "melon") = text "one melon" -- > speakNOf 3 (text "melon") = text "three melons" speakNOf :: Int -> SDoc -> SDoc speakNOf 0 d = text "no" <+> d <> char 's' speakNOf 1 d = text "one" <+> d -- E.g. "one argument" speakNOf n d = speakN n <+> d <> char 's' -- E.g. "three arguments" -- | Determines the pluralisation suffix appropriate for the length of a list: -- -- > plural [] = char 's' -- > plural ["Hello"] = empty -- > plural ["Hello", "World"] = char 's' plural :: [a] -> SDoc plural [_] = empty -- a bit frightening, but there you are plural _ = char 's' -- | Determines the singular verb suffix appropriate for the length of a list: -- -- > singular [] = empty -- > singular["Hello"] = char 's' -- > singular ["Hello", "World"] = empty singular :: [a] -> SDoc singular [_] = char 's' singular _ = empty -- | Determines the form of to be appropriate for the length of a list: -- -- > isOrAre [] = text "are" -- > isOrAre ["Hello"] = text "is" -- > isOrAre ["Hello", "World"] = text "are" isOrAre :: [a] -> SDoc isOrAre [_] = text "is" isOrAre _ = text "are" -- | Determines the form of to do appropriate for the length of a list: -- -- > doOrDoes [] = text "do" -- > doOrDoes ["Hello"] = text "does" -- > doOrDoes ["Hello", "World"] = text "do" doOrDoes :: [a] -> SDoc doOrDoes [_] = text "does" doOrDoes _ = text "do" -- | Determines the form of possessive appropriate for the length of a list: -- -- > itsOrTheir [x] = text "its" -- > itsOrTheir [x,y] = text "their" -- > itsOrTheir [] = text "their" -- probably avoid this itsOrTheir :: [a] -> SDoc itsOrTheir [_] = text "its" itsOrTheir _ = text "their" -- | Determines the form of subject appropriate for the length of a list: -- -- > thisOrThese [x] = text "This" -- > thisOrThese [x,y] = text "These" -- > thisOrThese [] = text "These" -- probably avoid this thisOrThese :: [a] -> SDoc thisOrThese [_] = text "This" thisOrThese _ = text "These" -- | @"has"@ or @"have"@ depending on the length of a list. hasOrHave :: [a] -> SDoc hasOrHave [_] = text "has" hasOrHave _ = text "have" {- Note [SDoc versus HDoc] ~~~~~~~~~~~~~~~~~~~~~~~~~~ The SDoc type is used pervasively throughout the compiler to represent pretty- printable output. Almost all text written by GHC, from the Haskell types and expressions included in error messages to debug dumps, is assembled using SDoc. SDoc is nice because it handles multiline layout in a semi-automatic fashion, enabling printed expressions to wrap to fit a given line width while correctly indenting the following lines to preserve alignment. SDoc’s niceties necessarily have some performance cost, but this is normally okay, as printing output is rarely a performance bottleneck. However, one notable exception to this is code generation: GHC must sometimes write megabytes’ worth of generated assembly when compiling a single module, in which case the overhead of SDoc has a significant cost (see #21853 for some numbers). Moreover, generated assembly does not have the complex layout requirements of pretty-printed Haskell code, so using SDoc does not buy us much, anyway. Nevertheless, we do still want to be able to share some logic between writing assembly and pretty-printing. For example, the logic for printing basic block labels (GHC.Cmm.CLabel.pprCLabel) is nontrivial, so we want to have a single implementation that can be used both when generating code and when generating Cmm dumps. This is where HDoc comes in: HDoc provides a subset of the SDoc interface, but it is implemented in a far more efficient way, writing directly to a `Handle` (via a `BufHandle`) without building any intermediate structures. We can then use typeclasses to parameterize functions like `pprCLabel` over the printing implementation. One might imagine this would result in one IsDoc typeclass, and two instances, one for SDoc and one for HDoc. However, in fact, we need two *variants* of HDoc, as described in Note [HLine versus HDoc], and this gives rise to a small typeclass hierarchy consisting of IsOutput, IsLine, and IsDoc; see Note [The outputable class hierarchy] for details. Note [HLine versus HDoc] ~~~~~~~~~~~~~~~~~~~~~~~~ As described in Note [SDoc versus HDoc], HDoc does not support any of the layout niceties of SDoc for efficiency. However, this presents a small problem if we want to be compatible with the SDoc API, as expressions like text "foo" <+> (text "bar" $$ text "baz") are expected to produce foo bar baz which requires tracking line widths to know how far to indent the second line. We can’t throw out vertical composition altogether, as we need to be able to construct multiline HDocs, but we *can* restrict vertical composition to concatenating whole lines at a time, as this is all that is necessary to generate assembly in the code generator. To implement this restriction, we provide two distinct types: HLine and HDoc. As their names suggests, an HLine represents a single line of output, while an HDoc represents a multiline document. Atoms formed from `char` and `text` begin their lives as HLines, which can be horizontally (but not vertically) composed: char :: Char -> HLine text :: String -> HLine (<+>) :: HLine -> HLine -> HLine Once a line has been fully assembled, it can be “locked up” into a single-line HDoc via `line`, and HDocs can be vertically (but not horizontally) composed: line :: HLine -> HDoc ($$) :: HLine -> HLine -> HLine Note that, at runtime, HLine and HDoc use exactly the same representation. This distinction only exists in the type system to rule out the cases we don’t want to have to handle. Note [The outputable class hierarchy] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As described in Note [SDoc versus HDoc], we want to be able to parameterize over the choice of printing implementation when implementing common bits of printing logic. However, as described in Note [HLine versus HDoc], we also want to distinguish code that does single-line printing from code that does multi-line printing. Therefore, code that is parameterized over the choice of printer must respect this single- versus multi-line distinction. This naturally leads to two typeclasses: class IsLine doc where char :: Char -> doc text :: String -> doc (<>) :: doc -> doc -> doc ... class IsLine (Line doc) => IsDoc doc where type Line doc = r | r -> doc line :: Line doc -> doc ($$) :: doc -> doc -> doc ... These classes support the following instances: instance IsLine SDoc instance IsLine SDoc where type Line SDoc = SDoc instance IsLine HLine instance IsDoc HDoc where type Line HDoc = HLine However, we run into a new problem: we provide many useful combinators on docs that don’t care at all about the single-/multi-line distinction. For example, ppWhen and ppUnless provide conditional logic, and docWithContext provides access to the ambient SDocContext. Given the above classes, we would need two variants of each of these combinators: ppWhenL :: IsLine doc => Bool -> doc -> doc ppWhenL c d = if c then d else emptyL ppWhenD :: IsDoc doc => Bool -> doc -> doc ppWhenD c d = if c then d else emptyD This is a needlessly annoying distinction, so we introduce a common superclass, IsOutput, that allows these combinators to be generic over both variants: class IsOutput doc where empty :: doc docWithContext :: (SDocContext -> doc) -> doc class IsOutput doc => IsLine doc class (IsOutput doc, IsLine (Line doc)) => IsDoc doc In practice, IsOutput isn’t used explicitly very often, but it makes code that uses the combinators derived from it significantly less noisy. Note [SPECIALIZE to HDoc] ~~~~~~~~~~~~~~~~~~~~~~~~~ The IsLine and IsDoc classes are useful to share printing logic between code that uses SDoc and code that uses HDoc, but we must take some care when doing so. Much HDoc’s efficiency comes from GHC’s ability to optimize code that uses it to eliminate unnecessary indirection, but the HDoc primitives must be inlined before these opportunities can be exposed. Therefore, we want to explicitly request that GHC generate HDoc (or HLine) specializations of any polymorphic printing functions used by the code generator. In code generators (CmmToAsm.{AArch64,PPC,X86}.Ppr) we add a specialize pragma just to the entry point pprNatCmmDecl, to avoid cluttering the entire module. Because specialization is transitive, this makes sure that other functions in that module are specialized too. Note [dualLine and dualDoc] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The IsLine and IsDoc classes provide the dualLine and dualDoc methods, respectively, which have the following types: dualLine :: IsLine doc => SDoc -> HLine -> doc dualDoc :: IsDoc doc => SDoc -> HDoc -> doc These are effectively a form of type-`case`, selecting between each of their two arguments depending on the type they are instantiated at. They serve as a “nuclear option” for code that is, for some reason or another, unreasonably difficult to make completely equivalent under both printer implementations. These operations should generally be avoided, as they can result in surprising changes in behavior when the printer implementation is changed. However, in certain cases, the alternative is even worse. For example, we use dualLine in the implementation of pprUnitId, as the hack we use for printing unit ids (see Note [Pretty-printing UnitId] in GHC.Unit) is difficult to adapt to HLine and is not necessary for code paths that use it, anyway. Use these operations wisely. -} -- | Represents a single line of output that can be efficiently printed directly -- to a 'System.IO.Handle' (actually a 'BufHandle'). -- See Note [SDoc versus HDoc] and Note [HLine versus HDoc] for more details. newtype HLine = HLine' { runHLine :: SDocContext -> BufHandle -> IO () } -- | Represents a (possibly empty) sequence of lines that can be efficiently -- printed directly to a 'System.IO.Handle' (actually a 'BufHandle'). -- See Note [SDoc versus HDoc] and Note [HLine versus HDoc] for more details. newtype HDoc = HDoc' { runHDoc :: SDocContext -> BufHandle -> IO () } -- See Note [The one-shot state monad trick] in GHC.Utils.Monad pattern HLine :: (SDocContext -> BufHandle -> IO ()) -> HLine pattern HLine f <- HLine' f where HLine f = HLine' (oneShot (\ctx -> oneShot (\h -> f ctx h))) {-# COMPLETE HLine #-} -- See Note [The one-shot state monad trick] in GHC.Utils.Monad pattern HDoc :: (SDocContext -> BufHandle -> IO ()) -> HDoc pattern HDoc f <- HDoc' f where HDoc f = HDoc' (oneShot (\ctx -> oneShot (\h -> f ctx h))) {-# COMPLETE HDoc #-} bPutHDoc :: BufHandle -> SDocContext -> HDoc -> IO () bPutHDoc h ctx (HDoc f) = f ctx h -- | A superclass for 'IsLine' and 'IsDoc' that provides an identity, 'empty', -- as well as access to the shared 'SDocContext'. -- -- See Note [The outputable class hierarchy] for more details. class IsOutput doc where empty :: doc docWithContext :: (SDocContext -> doc) -> doc -- | A class of types that represent a single logical line of text, with support -- for horizontal composition. -- -- See Note [HLine versus HDoc] and Note [The outputable class hierarchy] for -- more details. class IsOutput doc => IsLine doc where char :: Char -> doc text :: String -> doc ftext :: FastString -> doc ztext :: FastZString -> doc -- | Join two @doc@s together horizontally without a gap. (<>) :: doc -> doc -> doc -- | Join two @doc@s together horizontally with a gap between them. (<+>) :: doc -> doc -> doc -- | Separate: is either like 'hsep' or like 'vcat', depending on what fits. sep :: [doc] -> doc -- | A paragraph-fill combinator. It's much like 'sep', only it keeps fitting -- things on one line until it can't fit any more. fsep :: [doc] -> doc -- | Concatenate @doc@s horizontally without gaps. hcat :: [doc] -> doc hcat docs = foldr (<>) empty docs {-# INLINE CONLIKE hcat #-} -- | Concatenate @doc@s horizontally with a space between each one. hsep :: [doc] -> doc hsep docs = foldr (<+>) empty docs {-# INLINE CONLIKE hsep #-} -- | Prints as either the given 'SDoc' or the given 'HLine', depending on -- which type the result is instantiated to. This should generally be avoided; -- see Note [dualLine and dualDoc] for details. dualLine :: SDoc -> HLine -> doc -- | A class of types that represent a multiline document, with support for -- vertical composition. -- -- See Note [HLine versus HDoc] and Note [The outputable class hierarchy] for -- more details. class (IsOutput doc, IsLine (Line doc)) => IsDoc doc where type Line doc = r | r -> doc line :: Line doc -> doc -- | Join two @doc@s together vertically. If there is no vertical overlap it -- "dovetails" the two onto one line. ($$) :: doc -> doc -> doc lines_ :: [Line doc] -> doc lines_ = vcat . map line {-# INLINE CONLIKE lines_ #-} -- | Concatenate @doc@s vertically with dovetailing. vcat :: [doc] -> doc vcat ls = foldr ($$) empty ls {-# INLINE CONLIKE vcat #-} -- | Prints as either the given 'SDoc' or the given 'HDoc', depending on -- which type the result is instantiated to. This should generally be avoided; -- see Note [dualLine and dualDoc] for details. dualDoc :: SDoc -> HDoc -> doc instance IsOutput SDoc where empty = docToSDoc $ Pretty.empty {-# INLINE CONLIKE empty #-} docWithContext = sdocWithContext {-# INLINE docWithContext #-} instance IsLine SDoc where char c = docToSDoc $ Pretty.char c {-# INLINE CONLIKE char #-} text s = docToSDoc $ Pretty.text s {-# INLINE CONLIKE text #-} -- Inline so that the RULE Pretty.text will fire ftext s = docToSDoc $ Pretty.ftext s {-# INLINE CONLIKE ftext #-} ztext s = docToSDoc $ Pretty.ztext s {-# INLINE CONLIKE ztext #-} (<>) d1 d2 = SDoc $ \ctx -> (Pretty.<>) (runSDoc d1 ctx) (runSDoc d2 ctx) {-# INLINE CONLIKE (<>) #-} (<+>) d1 d2 = SDoc $ \ctx -> (Pretty.<+>) (runSDoc d1 ctx) (runSDoc d2 ctx) {-# INLINE CONLIKE (<+>) #-} hcat ds = SDoc $ \ctx -> Pretty.hcat [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE hcat #-} hsep ds = SDoc $ \ctx -> Pretty.hsep [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE hsep #-} sep ds = SDoc $ \ctx -> Pretty.sep [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE sep #-} fsep ds = SDoc $ \ctx -> Pretty.fsep [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE fsep #-} dualLine s _ = s {-# INLINE CONLIKE dualLine #-} instance IsDoc SDoc where type Line SDoc = SDoc line = id {-# INLINE line #-} lines_ = vcat {-# INLINE lines_ #-} ($$) d1 d2 = SDoc $ \ctx -> (Pretty.$$) (runSDoc d1 ctx) (runSDoc d2 ctx) {-# INLINE CONLIKE ($$) #-} vcat ds = SDoc $ \ctx -> Pretty.vcat [runSDoc d ctx | d <- ds] {-# INLINE CONLIKE vcat #-} dualDoc s _ = s {-# INLINE CONLIKE dualDoc #-} instance IsOutput HLine where empty = HLine (\_ _ -> pure ()) {-# INLINE empty #-} docWithContext f = HLine $ \ctx h -> runHLine (f ctx) ctx h {-# INLINE CONLIKE docWithContext #-} instance IsOutput HDoc where empty = HDoc (\_ _ -> pure ()) {-# INLINE empty #-} docWithContext f = HDoc $ \ctx h -> runHDoc (f ctx) ctx h {-# INLINE CONLIKE docWithContext #-} instance IsLine HLine where char c = HLine (\_ h -> bPutChar h c) {-# INLINE CONLIKE char #-} text str = HLine (\_ h -> bPutStr h str) {-# INLINE CONLIKE text #-} ftext fstr = HLine (\_ h -> bPutFS h fstr) {-# INLINE CONLIKE ftext #-} ztext fstr = HLine (\_ h -> bPutFZS h fstr) {-# INLINE CONLIKE ztext #-} HLine f <> HLine g = HLine (\ctx h -> f ctx h *> g ctx h) {-# INLINE CONLIKE (<>) #-} f <+> g = f <> char ' ' <> g {-# INLINE CONLIKE (<+>) #-} sep = hsep {-# INLINE sep #-} fsep = hsep {-# INLINE fsep #-} dualLine _ h = h {-# INLINE CONLIKE dualLine #-} instance IsDoc HDoc where type Line HDoc = HLine line (HLine f) = HDoc (\ctx h -> f ctx h *> bPutChar h '\n') {-# INLINE CONLIKE line #-} HDoc f $$ HDoc g = HDoc (\ctx h -> f ctx h *> g ctx h) {-# INLINE CONLIKE ($$) #-} dualDoc _ h = h {-# INLINE CONLIKE dualDoc #-}