\begin{code}
module BasicTypes(
- Version, Arity,
- Unused, unused,
+ Version, bumpVersion, initialVersion,
+
+ Arity,
+
+ DeprecTxt,
+
Fixity(..), FixityDirection(..),
- defaultFixity, maxPrecedence, negateFixity, negatePrecedence,
- NewOrData(..),
- RecFlag(..), isRec, isNonRec,
- TopLevelFlag(..), isTopLevel, isNotTopLevel
+ defaultFixity, maxPrecedence,
+ negateFixity,
+ compareFixity,
+
+ IPName(..), ipNameName, mapIPName,
+
+ RecFlag(..), isRec, isNonRec, boolToRecFlag,
+
+ TopLevelFlag(..), isTopLevel, isNotTopLevel,
+
+ Boxity(..), isBoxed,
+
+ TupCon(..), tupleParens,
+
+ OccInfo(..), seqOccInfo, isFragileOcc, isOneOcc,
+ isDeadOcc, isLoopBreaker,
+
+ InsideLam, insideLam, notInsideLam,
+ OneBranch, oneBranch, notOneBranch,
+
+ EP(..),
+
+ StrictnessMark(..), isMarkedUnboxed, isMarkedStrict,
+
+ CompilerPhase,
+ Activation(..), isActive, isNeverActive, isAlwaysActive,
+
+ SuccessFlag(..), succeeded, failed, successIf
) where
#include "HsVersions.h"
+import FastString( FastString )
import Outputable
\end{code}
%************************************************************************
%* *
-\subsection[Unused]{Unused}
+\subsection[Arity]{Arity}
%* *
%************************************************************************
-Used as a placeholder in types.
-
\begin{code}
-type Unused = ()
-
-unused :: Unused
-unused = error "Unused is used!"
+type Arity = Int
\end{code}
%************************************************************************
%* *
-\subsection[Arity]{Arity}
+\subsection[Version]{Module and identifier version numbers}
%* *
%************************************************************************
\begin{code}
-type Arity = Int
+type Version = Int
+
+bumpVersion :: Version -> Version
+bumpVersion v = v+1
+
+initialVersion :: Version
+initialVersion = 1
\end{code}
+%************************************************************************
+%* *
+ Deprecations
+%* *
+%************************************************************************
+
+
+\begin{code}
+type DeprecTxt = FastString -- reason/explanation for deprecation
+\end{code}
%************************************************************************
%* *
-\subsection[Version]{Module and identifier version numbers}
+\subsection{Implicit parameter identity}
%* *
%************************************************************************
+The @IPName@ type is here because it is used in TypeRep (i.e. very
+early in the hierarchy), but also in HsSyn.
+
\begin{code}
-type Version = Int
+data IPName name
+ = Dupable name -- ?x: you can freely duplicate this implicit parameter
+ | Linear name -- %x: you must use the splitting function to duplicate it
+ deriving( Eq, Ord ) -- Ord is used in the IP name cache finite map
+ -- (used in HscTypes.OrigIParamCache)
+
+
+ipNameName :: IPName name -> name
+ipNameName (Dupable n) = n
+ipNameName (Linear n) = n
+
+mapIPName :: (a->b) -> IPName a -> IPName b
+mapIPName f (Dupable n) = Dupable (f n)
+mapIPName f (Linear n) = Linear (f n)
+
+instance Outputable name => Outputable (IPName name) where
+ ppr (Dupable n) = char '?' <> ppr n -- Ordinary implicit parameters
+ ppr (Linear n) = char '%' <> ppr n -- Splittable implicit parameters
\end{code}
%************************************************************************
\begin{code}
+------------------------
data Fixity = Fixity Int FixityDirection
-data FixityDirection = InfixL | InfixR | InfixN
- deriving(Eq)
instance Outputable Fixity where
ppr (Fixity prec dir) = hcat [ppr dir, space, int prec]
+instance Eq Fixity where -- Used to determine if two fixities conflict
+ (Fixity p1 dir1) == (Fixity p2 dir2) = p1==p2 && dir1 == dir2
+
+------------------------
+data FixityDirection = InfixL | InfixR | InfixN
+ deriving(Eq)
+
instance Outputable FixityDirection where
ppr InfixL = ptext SLIT("infixl")
ppr InfixR = ptext SLIT("infixr")
ppr InfixN = ptext SLIT("infix")
-instance Eq Fixity where -- Used to determine if two fixities conflict
- (Fixity p1 dir1) == (Fixity p2 dir2) = p1==p2 && dir1 == dir2
-
+------------------------
maxPrecedence = (9::Int)
defaultFixity = Fixity maxPrecedence InfixL
negatePrecedence = 6
\end{code}
+Consider
-%************************************************************************
-%* *
-\subsection[NewType/DataType]{NewType/DataType flag}
-%* *
-%************************************************************************
+\begin{verbatim}
+ a `op1` b `op2` c
+\end{verbatim}
+@(compareFixity op1 op2)@ tells which way to arrange appication, or
+whether there's an error.
\begin{code}
-data NewOrData
- = NewType -- "newtype Blah ..."
- | DataType -- "data Blah ..."
- | EnumType -- Enumeration; all constructors are nullary
- deriving( Eq ) -- Needed because Demand derives Eq
+compareFixity :: Fixity -> Fixity
+ -> (Bool, -- Error please
+ Bool) -- Associate to the right: a op1 (b op2 c)
+compareFixity (Fixity prec1 dir1) (Fixity prec2 dir2)
+ = case prec1 `compare` prec2 of
+ GT -> left
+ LT -> right
+ EQ -> case (dir1, dir2) of
+ (InfixR, InfixR) -> right
+ (InfixL, InfixL) -> left
+ _ -> error_please
+ where
+ right = (False, True)
+ left = (False, False)
+ error_please = (True, False)
\end{code}
+
%************************************************************************
%* *
\subsection[Top-level/local]{Top-level/not-top level flag}
isTopLevel TopLevel = True
isTopLevel NotTopLevel = False
+
+instance Outputable TopLevelFlag where
+ ppr TopLevel = ptext SLIT("<TopLevel>")
+ ppr NotTopLevel = ptext SLIT("<NotTopLevel>")
\end{code}
+
+%************************************************************************
+%* *
+\subsection[Top-level/local]{Top-level/not-top level flag}
+%* *
+%************************************************************************
+
+\begin{code}
+data Boxity
+ = Boxed
+ | Unboxed
+ deriving( Eq )
+
+isBoxed :: Boxity -> Bool
+isBoxed Boxed = True
+isBoxed Unboxed = False
+\end{code}
+
+
%************************************************************************
%* *
\subsection[Recursive/Non-Recursive]{Recursive/Non-Recursive flag}
\begin{code}
data RecFlag = Recursive
| NonRecursive
+ deriving( Eq )
isRec :: RecFlag -> Bool
isRec Recursive = True
isNonRec :: RecFlag -> Bool
isNonRec Recursive = False
isNonRec NonRecursive = True
+
+boolToRecFlag :: Bool -> RecFlag
+boolToRecFlag True = Recursive
+boolToRecFlag False = NonRecursive
+
+instance Outputable RecFlag where
+ ppr Recursive = ptext SLIT("Recursive")
+ ppr NonRecursive = ptext SLIT("NonRecursive")
+\end{code}
+
+%************************************************************************
+%* *
+ Tuples
+%* *
+%************************************************************************
+
+\begin{code}
+data TupCon = TupCon Boxity Arity
+
+instance Eq TupCon where
+ (TupCon b1 a1) == (TupCon b2 a2) = b1==b2 && a1==a2
+
+tupleParens :: Boxity -> SDoc -> SDoc
+tupleParens Boxed p = parens p
+tupleParens Unboxed p = ptext SLIT("(#") <+> p <+> ptext SLIT("#)")
+\end{code}
+
+%************************************************************************
+%* *
+\subsection[Generic]{Generic flag}
+%* *
+%************************************************************************
+
+This is the "Embedding-Projection pair" datatype, it contains
+two pieces of code (normally either RenamedExpr's or Id's)
+If we have a such a pair (EP from to), the idea is that 'from' and 'to'
+represents functions of type
+
+ from :: T -> Tring
+ to :: Tring -> T
+
+And we should have
+
+ to (from x) = x
+
+T and Tring are arbitrary, but typically T is the 'main' type while
+Tring is the 'representation' type. (This just helps us remember
+whether to use 'from' or 'to'.
+
+\begin{code}
+data EP a = EP { fromEP :: a, -- :: T -> Tring
+ toEP :: a } -- :: Tring -> T
+\end{code}
+
+Embedding-projection pairs are used in several places:
+
+First of all, each type constructor has an EP associated with it, the
+code in EP converts (datatype T) from T to Tring and back again.
+
+Secondly, when we are filling in Generic methods (in the typechecker,
+tcMethodBinds), we are constructing bimaps by induction on the structure
+of the type of the method signature.
+
+
+%************************************************************************
+%* *
+\subsection{Occurrence information}
+%* *
+%************************************************************************
+
+This data type is used exclusively by the simplifier, but it appears in a
+SubstResult, which is currently defined in VarEnv, which is pretty near
+the base of the module hierarchy. So it seemed simpler to put the
+defn of OccInfo here, safely at the bottom
+
+\begin{code}
+data OccInfo
+ = NoOccInfo
+
+ | IAmDead -- Marks unused variables. Sometimes useful for
+ -- lambda and case-bound variables.
+
+ | OneOcc InsideLam
+
+ OneBranch
+
+ | IAmALoopBreaker -- Used by the occurrence analyser to mark loop-breakers
+ -- in a group of recursive definitions
+
+seqOccInfo :: OccInfo -> ()
+seqOccInfo (OneOcc in_lam once) = in_lam `seq` once `seq` ()
+seqOccInfo occ = ()
+
+type InsideLam = Bool -- True <=> Occurs inside a non-linear lambda
+ -- Substituting a redex for this occurrence is
+ -- dangerous because it might duplicate work.
+insideLam = True
+notInsideLam = False
+
+type OneBranch = Bool -- True <=> Occurs in only one case branch
+ -- so no code-duplication issue to worry about
+oneBranch = True
+notOneBranch = False
+
+isLoopBreaker :: OccInfo -> Bool
+isLoopBreaker IAmALoopBreaker = True
+isLoopBreaker other = False
+
+isDeadOcc :: OccInfo -> Bool
+isDeadOcc IAmDead = True
+isDeadOcc other = False
+
+isOneOcc (OneOcc _ _) = True
+isOneOcc other = False
+
+isFragileOcc :: OccInfo -> Bool
+isFragileOcc (OneOcc _ _) = True
+isFragileOcc other = False
+\end{code}
+
+\begin{code}
+instance Outputable OccInfo where
+ -- only used for debugging; never parsed. KSW 1999-07
+ ppr NoOccInfo = empty
+ ppr IAmALoopBreaker = ptext SLIT("LoopBreaker")
+ ppr IAmDead = ptext SLIT("Dead")
+ ppr (OneOcc inside_lam one_branch) | inside_lam = ptext SLIT("OnceInLam")
+ | one_branch = ptext SLIT("Once")
+ | otherwise = ptext SLIT("OnceEachBranch")
+
+instance Show OccInfo where
+ showsPrec p occ = showsPrecSDoc p (ppr occ)
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Strictness indication}
+%* *
+%************************************************************************
+
+The strictness annotations on types in data type declarations
+e.g. data T = MkT !Int !(Bool,Bool)
+
+\begin{code}
+data StrictnessMark -- Used in interface decls only
+ = MarkedStrict
+ | MarkedUnboxed
+ | NotMarkedStrict
+ deriving( Eq )
+
+isMarkedUnboxed MarkedUnboxed = True
+isMarkedUnboxed other = False
+
+isMarkedStrict NotMarkedStrict = False
+isMarkedStrict other = True -- All others are strict
+
+instance Outputable StrictnessMark where
+ ppr MarkedStrict = ptext SLIT("!")
+ ppr MarkedUnboxed = ptext SLIT("!!")
+ ppr NotMarkedStrict = ptext SLIT("_")
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Success flag}
+%* *
+%************************************************************************
+
+\begin{code}
+data SuccessFlag = Succeeded | Failed
+
+successIf :: Bool -> SuccessFlag
+successIf True = Succeeded
+successIf False = Failed
+
+succeeded, failed :: SuccessFlag -> Bool
+succeeded Succeeded = True
+succeeded Failed = False
+
+failed Succeeded = False
+failed Failed = True
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Activation}
+%* *
+%************************************************************************
+
+When a rule or inlining is active
+
+\begin{code}
+type CompilerPhase = Int -- Compilation phase
+ -- Phases decrease towards zero
+ -- Zero is the last phase
+
+data Activation = NeverActive
+ | AlwaysActive
+ | ActiveBefore CompilerPhase -- Active only *before* this phase
+ | ActiveAfter CompilerPhase -- Active in this phase and later
+ deriving( Eq ) -- Eq used in comparing rules in HsDecls
+
+instance Outputable Activation where
+ ppr AlwaysActive = empty -- The default
+ ppr (ActiveBefore n) = brackets (char '~' <> int n)
+ ppr (ActiveAfter n) = brackets (int n)
+ ppr NeverActive = ptext SLIT("NEVER")
+
+isActive :: CompilerPhase -> Activation -> Bool
+isActive p NeverActive = False
+isActive p AlwaysActive = True
+isActive p (ActiveAfter n) = p <= n
+isActive p (ActiveBefore n) = p > n
+
+isNeverActive, isAlwaysActive :: Activation -> Bool
+isNeverActive NeverActive = True
+isNeverActive act = False
+
+isAlwaysActive AlwaysActive = True
+isAlwaysActive other = False
+\end{code}
+
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