-- friends:
import HsDecls ( HsGroup )
-import HsBinds ( HsBinds(..), nullBinds )
-import HsPat ( Pat )
-import HsLit ( HsLit, HsOverLit )
-import HsTypes ( HsType, PostTcType, SyntaxName )
+import HsPat ( LPat )
+import HsLit ( HsLit(..), HsOverLit )
+import HsTypes ( LHsType, PostTcType )
import HsImpExp ( isOperator, pprHsVar )
+import HsBinds ( HsLocalBinds, DictBinds, ExprCoFn, isEmptyLocalBinds )
-- others:
-import ForeignCall ( Safety )
-import PprType ( pprParendType )
-import Type ( Type, TyThing )
+import Type ( Type, pprParendType )
import Var ( TyVar, Id )
import Name ( Name )
-import DataCon ( DataCon )
-import CStrings ( CLabelString, pprCLabelString )
-import BasicTypes ( IPName, Boxity, tupleParens, Fixity(..) )
-import SrcLoc ( SrcLoc )
+import BasicTypes ( IPName, Boxity, tupleParens, Arity, Fixity(..) )
+import SrcLoc ( Located(..), unLoc )
import Outputable
import FastString
\end{code}
+
%************************************************************************
%* *
\subsection{Expressions proper}
%************************************************************************
\begin{code}
+type LHsExpr id = Located (HsExpr id)
+
+-------------------------
+-- PostTcExpr is an evidence expression attached to the
+-- syntax tree by the type checker (c.f. postTcType)
+-- We use a PostTcTable where there are a bunch of pieces of
+-- evidence, more than is convenient to keep individually
+type PostTcExpr = HsExpr Id
+type PostTcTable = [(Name, Id)]
+
+noPostTcExpr :: PostTcExpr
+noPostTcExpr = HsLit (HsString FSLIT("noPostTcExpr"))
+
+noPostTcTable :: PostTcTable
+noPostTcTable = []
+
+-------------------------
+-- SyntaxExpr is like PostTcExpr, but it's filled in a little earlier,
+-- by the renamer. It's used for rebindable syntax.
+-- E.g. (>>=) is filled in before the renamer by the appropriate Name
+-- for (>>=), and then instantiated by the type checker with its
+-- type args tec
+
+type SyntaxExpr id = HsExpr id
+
+noSyntaxExpr :: SyntaxExpr id -- Before renaming, and sometimes after,
+ -- (if the syntax slot makes no sense)
+noSyntaxExpr = HsLit (HsString FSLIT("noSyntaxExpr"))
+
+
+type SyntaxTable id = [(Name, SyntaxExpr id)]
+-- *** Currently used only for CmdTop (sigh) ***
+-- * Before the renamer, this list is noSyntaxTable
+--
+-- * After the renamer, it takes the form [(std_name, HsVar actual_name)]
+-- For example, for the 'return' op of a monad
+-- normal case: (GHC.Base.return, HsVar GHC.Base.return)
+-- with rebindable syntax: (GHC.Base.return, return_22)
+-- where return_22 is whatever "return" is in scope
+--
+-- * After the type checker, it takes the form [(std_name, <expression>)]
+-- where <expression> is the evidence for the method
+
+noSyntaxTable :: SyntaxTable id
+noSyntaxTable = []
+
+
+-------------------------
data HsExpr id
= HsVar id -- variable
| HsIPVar (IPName id) -- implicit parameter
- | HsOverLit HsOverLit -- Overloaded literals; eliminated by type checker
+ | HsOverLit (HsOverLit id) -- Overloaded literals
| HsLit HsLit -- Simple (non-overloaded) literals
- | HsLam (Match id) -- lambda
- | HsApp (HsExpr id) -- application
- (HsExpr id)
+ | HsLam (MatchGroup id) -- Currently always a single match
+
+ | HsApp (LHsExpr id) -- Application
+ (LHsExpr id)
-- Operator applications:
-- NB Bracketed ops such as (+) come out as Vars.
-- NB We need an expr for the operator in an OpApp/Section since
-- the typechecker may need to apply the operator to a few types.
- | OpApp (HsExpr id) -- left operand
- (HsExpr id) -- operator
- Fixity -- Renamer adds fixity; bottom until then
- (HsExpr id) -- right operand
-
- -- We preserve prefix negation and parenthesis for the precedence parser.
- -- They are eventually removed by the type checker.
+ | OpApp (LHsExpr id) -- left operand
+ (LHsExpr id) -- operator
+ Fixity -- Renamer adds fixity; bottom until then
+ (LHsExpr id) -- right operand
- | NegApp (HsExpr id) -- negated expr
- SyntaxName -- Name of 'negate' (see RnEnv.lookupSyntaxName)
+ | NegApp (LHsExpr id) -- negated expr
+ (SyntaxExpr id) -- Name of 'negate'
- | HsPar (HsExpr id) -- parenthesised expr
+ | HsPar (LHsExpr id) -- parenthesised expr
- | SectionL (HsExpr id) -- operand
- (HsExpr id) -- operator
- | SectionR (HsExpr id) -- operator
- (HsExpr id) -- operand
+ | SectionL (LHsExpr id) -- operand
+ (LHsExpr id) -- operator
+ | SectionR (LHsExpr id) -- operator
+ (LHsExpr id) -- operand
- | HsCase (HsExpr id)
- [Match id]
- SrcLoc
+ | HsCase (LHsExpr id)
+ (MatchGroup id)
- | HsIf (HsExpr id) -- predicate
- (HsExpr id) -- then part
- (HsExpr id) -- else part
- SrcLoc
+ | HsIf (LHsExpr id) -- predicate
+ (LHsExpr id) -- then part
+ (LHsExpr id) -- else part
- | HsLet (HsBinds id) -- let(rec)
- (HsExpr id)
+ | HsLet (HsLocalBinds id) -- let(rec)
+ (LHsExpr id)
| HsDo (HsStmtContext Name) -- The parameterisation is unimportant
-- because in this context we never use
-- the PatGuard or ParStmt variant
- [Stmt id] -- "do":one or more stmts
- [id] -- Ids for [return,fail,>>=,>>]
- -- Brutal but simple
- -- Before type checking, used for rebindable syntax
- PostTcType -- Type of the whole expression
- SrcLoc
+ [LStmt id] -- "do":one or more stmts
+ (LHsExpr id) -- The body; the last expression in the 'do'
+ -- of [ body | ... ] in a list comp
+ PostTcType -- Type of the whole expression
| ExplicitList -- syntactic list
PostTcType -- Gives type of components of list
- [HsExpr id]
+ [LHsExpr id]
| ExplicitPArr -- syntactic parallel array: [:e1, ..., en:]
PostTcType -- type of elements of the parallel array
- [HsExpr id]
+ [LHsExpr id]
| ExplicitTuple -- tuple
- [HsExpr id]
+ [LHsExpr id]
-- NB: Unit is ExplicitTuple []
-- for tuples, we can get the types
-- direct from the components
-- Record construction
- | RecordCon id -- The constructor
+ | RecordCon (Located id) -- The constructor. After type checking
+ -- it's the dataConWrapId of the constructor
+ PostTcExpr -- Data con Id applied to type args
(HsRecordBinds id)
- | RecordConOut DataCon
- (HsExpr id) -- Data con Id applied to type args
- (HsRecordBinds id)
-
-
-- Record update
- | RecordUpd (HsExpr id)
+ | RecordUpd (LHsExpr id)
(HsRecordBinds id)
-
- | RecordUpdOut (HsExpr id) -- TRANSLATION
- Type -- Type of *input* record
- Type -- Type of *result* record (may differ from
+ PostTcType -- Type of *input* record
+ PostTcType -- Type of *result* record (may differ from
-- type of input record)
- (HsRecordBinds id)
- | ExprWithTySig -- signature binding
- (HsExpr id)
- (HsType id)
- | ArithSeqIn -- arithmetic sequence
- (ArithSeqInfo id)
- | ArithSeqOut
- (HsExpr id) -- (typechecked, of course)
- (ArithSeqInfo id)
- | PArrSeqIn -- arith. sequence for parallel array
- (ArithSeqInfo id) -- [:e1..e2:] or [:e1, e2..e3:]
- | PArrSeqOut
- (HsExpr id) -- (typechecked, of course)
+ | ExprWithTySig -- e :: type
+ (LHsExpr id)
+ (LHsType id)
+
+ | ExprWithTySigOut -- TRANSLATION
+ (LHsExpr id)
+ (LHsType Name) -- Retain the signature for round-tripping purposes
+
+ | ArithSeq -- arithmetic sequence
+ PostTcExpr
(ArithSeqInfo id)
- | HsCCall CLabelString -- call into the C world; string is
- [HsExpr id] -- the C function; exprs are the
- -- arguments to pass.
- Safety -- True <=> might cause Haskell
- -- garbage-collection (must generate
- -- more paranoid code)
- Bool -- True <=> it's really a "casm"
- -- NOTE: this CCall is the *boxed*
- -- version; the desugarer will convert
- -- it into the unboxed "ccall#".
- PostTcType -- The result type; will be *bottom*
- -- until the typechecker gets ahold of it
+ | PArrSeq -- arith. sequence for parallel array
+ PostTcExpr -- [:e1..e2:] or [:e1, e2..e3:]
+ (ArithSeqInfo id)
| HsSCC FastString -- "set cost centre" (_scc_) annotation
- (HsExpr id) -- expr whose cost is to be measured
+ (LHsExpr id) -- expr whose cost is to be measured
+
+ | HsCoreAnn FastString -- hdaume: core annotation
+ (LHsExpr id)
+ -----------------------------------------------------------
-- MetaHaskell Extensions
- | HsBracket (HsBracket id) SrcLoc
+ | HsBracket (HsBracket id)
| HsBracketOut (HsBracket Name) -- Output of the type checker is the *original*
[PendingSplice] -- renamed expression, plus *typechecked* splices
-- to be pasted back in by the desugarer
- | HsSplice id (HsExpr id) SrcLoc -- $z or $(f 4)
- -- The id is just a unique name to
- -- identify this splice point
-
- | HsReify (HsReify id) -- reifyType t, reifyDecl i, reifyFixity
+ | HsSpliceE (HsSplice id)
+
+ -----------------------------------------------------------
+ -- Arrow notation extension
+
+ | HsProc (LPat id) -- arrow abstraction, proc
+ (LHsCmdTop id) -- body of the abstraction
+ -- always has an empty stack
+
+ ---------------------------------------
+ -- The following are commands, not expressions proper
+
+ | HsArrApp -- Arrow tail, or arrow application (f -< arg)
+ (LHsExpr id) -- arrow expression, f
+ (LHsExpr id) -- input expression, arg
+ PostTcType -- type of the arrow expressions f,
+ -- of the form a t t', where arg :: t
+ HsArrAppType -- higher-order (-<<) or first-order (-<)
+ Bool -- True => right-to-left (f -< arg)
+ -- False => left-to-right (arg >- f)
+
+ | HsArrForm -- Command formation, (| e cmd1 .. cmdn |)
+ (LHsExpr id) -- the operator
+ -- after type-checking, a type abstraction to be
+ -- applied to the type of the local environment tuple
+ (Maybe Fixity) -- fixity (filled in by the renamer), for forms that
+ -- were converted from OpApp's by the renamer
+ [LHsCmdTop id] -- argument commands
\end{code}
\begin{code}
| EWildPat -- wildcard
- | EAsPat id -- as pattern
- (HsExpr id)
+ | EAsPat (Located id) -- as pattern
+ (LHsExpr id)
- | ELazyPat (HsExpr id) -- ~ pattern
+ | ELazyPat (LHsExpr id) -- ~ pattern
- | HsType (HsType id) -- Explicit type argument; e.g f {| Int |} x y
+ | HsType (LHsType id) -- Explicit type argument; e.g f {| Int |} x y
\end{code}
Everything from here on appears only in typechecker output.
\begin{code}
| TyLam -- TRANSLATION
[TyVar]
- (HsExpr id)
+ (LHsExpr id)
| TyApp -- TRANSLATION
- (HsExpr id) -- generated by Spec
+ (LHsExpr id) -- generated by Spec
[Type]
-- DictLam and DictApp are "inverses"
| DictLam
[id]
- (HsExpr id)
+ (LHsExpr id)
| DictApp
- (HsExpr id)
+ (LHsExpr id)
[id]
-type PendingSplice = (Name, HsExpr Id) -- Typechecked splices, waiting to be
+ | HsCoerce ExprCoFn -- TRANSLATION
+ (HsExpr id)
+
+type PendingSplice = (Name, LHsExpr Id) -- Typechecked splices, waiting to be
-- pasted back in by the desugarer
\end{code}
-
A @Dictionary@, unless of length 0 or 1, becomes a tuple. A
@ClassDictLam dictvars methods expr@ is, therefore:
\begin{verbatim}
pprExpr :: OutputableBndr id => HsExpr id -> SDoc
pprExpr e = pprDeeper (ppr_expr e)
+
+pprBinds :: OutputableBndr id => HsLocalBinds id -> SDoc
pprBinds b = pprDeeper (ppr b)
+ppr_lexpr :: OutputableBndr id => LHsExpr id -> SDoc
+ppr_lexpr e = ppr_expr (unLoc e)
+
ppr_expr (HsVar v) = pprHsVar v
ppr_expr (HsIPVar v) = ppr v
ppr_expr (HsLit lit) = ppr lit
ppr_expr (HsOverLit lit) = ppr lit
-ppr_expr (HsLam match) = pprMatch LambdaExpr match
-
-ppr_expr expr@(HsApp e1 e2)
- = let (fun, args) = collect_args expr [] in
- (ppr_expr fun) <+> (sep (map ppr_expr args))
+ppr_expr (HsApp e1 e2)
+ = let (fun, args) = collect_args e1 [e2] in
+ (ppr_lexpr fun) <+> (sep (map pprParendExpr args))
where
- collect_args (HsApp fun arg) args = collect_args fun (arg:args)
- collect_args fun args = (fun, args)
+ collect_args (L _ (HsApp fun arg)) args = collect_args fun (arg:args)
+ collect_args fun args = (fun, args)
ppr_expr (OpApp e1 op fixity e2)
- = case op of
+ = case unLoc op of
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
pp_e2 = pprParendExpr e2
pp_prefixly
- = hang (pprExpr op) 4 (sep [pp_e1, pp_e2])
+ = hang (ppr op) 4 (sep [pp_e1, pp_e2])
pp_infixly v
- = sep [pp_e1, hsep [pp_v_op, pp_e2]]
- where
- ppr_v = ppr v
- pp_v_op | isOperator ppr_v = ppr_v
- | otherwise = char '`' <> ppr_v <> char '`'
- -- Put it in backquotes if it's not an operator already
+ = sep [pp_e1, hsep [pprInfix v, pp_e2]]
ppr_expr (NegApp e _) = char '-' <+> pprParendExpr e
-ppr_expr (HsPar e) = parens (ppr_expr e)
+ppr_expr (HsPar e) = parens (ppr_lexpr e)
ppr_expr (SectionL expr op)
- = case op of
+ = case unLoc op of
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
pp_prefixly = hang (hsep [text " \\ x_ ->", ppr op])
4 (hsep [pp_expr, ptext SLIT("x_ )")])
- pp_infixly v = parens (sep [pp_expr, ppr v])
+ pp_infixly v = parens (sep [pp_expr, pprInfix v])
ppr_expr (SectionR op expr)
- = case op of
+ = case unLoc op of
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
pp_prefixly = hang (hsep [text "( \\ x_ ->", ppr op, ptext SLIT("x_")])
4 ((<>) pp_expr rparen)
pp_infixly v
- = parens (sep [ppr v, pp_expr])
+ = parens (sep [pprInfix v, pp_expr])
-ppr_expr (HsCase expr matches _)
- = sep [ sep [ptext SLIT("case"), nest 4 (pprExpr expr), ptext SLIT("of")],
+ppr_expr (HsLam matches)
+ = pprMatches LambdaExpr matches
+
+ppr_expr (HsCase expr matches)
+ = sep [ sep [ptext SLIT("case"), nest 4 (ppr expr), ptext SLIT("of")],
nest 2 (pprMatches CaseAlt matches) ]
-ppr_expr (HsIf e1 e2 e3 _)
- = sep [hsep [ptext SLIT("if"), nest 2 (pprExpr e1), ptext SLIT("then")],
- nest 4 (pprExpr e2),
+ppr_expr (HsIf e1 e2 e3)
+ = sep [hsep [ptext SLIT("if"), nest 2 (ppr e1), ptext SLIT("then")],
+ nest 4 (ppr e2),
ptext SLIT("else"),
- nest 4 (pprExpr e3)]
+ nest 4 (ppr e3)]
-- special case: let ... in let ...
-ppr_expr (HsLet binds expr@(HsLet _ _))
+ppr_expr (HsLet binds expr@(L _ (HsLet _ _)))
= sep [hang (ptext SLIT("let")) 2 (hsep [pprBinds binds, ptext SLIT("in")]),
- pprExpr expr]
+ ppr_lexpr expr]
ppr_expr (HsLet binds expr)
= sep [hang (ptext SLIT("let")) 2 (pprBinds binds),
hang (ptext SLIT("in")) 2 (ppr expr)]
-ppr_expr (HsDo do_or_list_comp stmts _ _ _) = pprDo do_or_list_comp stmts
+ppr_expr (HsDo do_or_list_comp stmts body _) = pprDo do_or_list_comp stmts body
ppr_expr (ExplicitList _ exprs)
- = brackets (fsep (punctuate comma (map ppr_expr exprs)))
+ = brackets (fsep (punctuate comma (map ppr_lexpr exprs)))
ppr_expr (ExplicitPArr _ exprs)
- = pa_brackets (fsep (punctuate comma (map ppr_expr exprs)))
+ = pa_brackets (fsep (punctuate comma (map ppr_lexpr exprs)))
ppr_expr (ExplicitTuple exprs boxity)
- = tupleParens boxity (sep (punctuate comma (map ppr_expr exprs)))
+ = tupleParens boxity (sep (punctuate comma (map ppr_lexpr exprs)))
-ppr_expr (RecordCon con_id rbinds)
+ppr_expr (RecordCon con_id con_expr rbinds)
= pp_rbinds (ppr con_id) rbinds
-ppr_expr (RecordConOut data_con con rbinds)
- = pp_rbinds (ppr con) rbinds
-ppr_expr (RecordUpd aexp rbinds)
- = pp_rbinds (pprParendExpr aexp) rbinds
-ppr_expr (RecordUpdOut aexp _ _ rbinds)
+ppr_expr (RecordUpd aexp rbinds _ _)
= pp_rbinds (pprParendExpr aexp) rbinds
ppr_expr (ExprWithTySig expr sig)
- = hang (nest 2 (ppr_expr expr) <+> dcolon)
+ = hang (nest 2 (ppr_lexpr expr) <+> dcolon)
+ 4 (ppr sig)
+ppr_expr (ExprWithTySigOut expr sig)
+ = hang (nest 2 (ppr_lexpr expr) <+> dcolon)
4 (ppr sig)
-ppr_expr (ArithSeqIn info)
- = brackets (ppr info)
-ppr_expr (ArithSeqOut expr info)
- = brackets (ppr info)
-
-ppr_expr (PArrSeqIn info)
- = pa_brackets (ppr info)
-ppr_expr (PArrSeqOut expr info)
- = pa_brackets (ppr info)
+ppr_expr (ArithSeq expr info) = brackets (ppr info)
+ppr_expr (PArrSeq expr info) = pa_brackets (ppr info)
-ppr_expr EWildPat = char '_'
+ppr_expr EWildPat = char '_'
ppr_expr (ELazyPat e) = char '~' <> pprParendExpr e
ppr_expr (EAsPat v e) = ppr v <> char '@' <> pprParendExpr e
-ppr_expr (HsCCall fun args _ is_asm result_ty)
- = hang (if is_asm
- then ptext SLIT("_casm_ ``") <> pprCLabelString fun <> ptext SLIT("''")
- else ptext SLIT("_ccall_") <+> pprCLabelString fun)
- 4 (sep (map pprParendExpr args))
-
ppr_expr (HsSCC lbl expr)
= sep [ ptext SLIT("_scc_") <+> doubleQuotes (ftext lbl), pprParendExpr expr ]
= hang (hsep [ptext SLIT("/\\"),
hsep (map (pprBndr LambdaBind) tyvars),
ptext SLIT("->")])
- 4 (ppr_expr expr)
+ 4 (ppr_lexpr expr)
ppr_expr (TyApp expr [ty])
- = hang (ppr_expr expr) 4 (pprParendType ty)
+ = hang (ppr_lexpr expr) 4 (pprParendType ty)
ppr_expr (TyApp expr tys)
- = hang (ppr_expr expr)
+ = hang (ppr_lexpr expr)
4 (brackets (interpp'SP tys))
ppr_expr (DictLam dictvars expr)
= hang (hsep [ptext SLIT("\\{-dict-}"),
hsep (map (pprBndr LambdaBind) dictvars),
ptext SLIT("->")])
- 4 (ppr_expr expr)
+ 4 (ppr_lexpr expr)
ppr_expr (DictApp expr [dname])
- = hang (ppr_expr expr) 4 (ppr dname)
+ = hang (ppr_lexpr expr) 4 (ppr dname)
ppr_expr (DictApp expr dnames)
- = hang (ppr_expr expr)
+ = hang (ppr_lexpr expr)
4 (brackets (interpp'SP dnames))
+ppr_expr (HsCoerce co_fn e) = ppr_expr e
+
ppr_expr (HsType id) = ppr id
-ppr_expr (HsSplice n e _) = char '$' <> brackets (ppr n) <> pprParendExpr e
-ppr_expr (HsBracket b _) = pprHsBracket b
-ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("where") <+> ppr ps
-ppr_expr (HsReify r) = ppr r
+ppr_expr (HsSpliceE s) = pprSplice s
+ppr_expr (HsBracket b) = pprHsBracket b
+ppr_expr (HsBracketOut e []) = ppr e
+ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("pending") <+> ppr ps
+
+ppr_expr (HsProc pat (L _ (HsCmdTop cmd _ _ _)))
+ = hsep [ptext SLIT("proc"), ppr pat, ptext SLIT("->"), ppr cmd]
+
+ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp True)
+ = hsep [ppr_lexpr arrow, ptext SLIT("-<"), ppr_lexpr arg]
+ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp False)
+ = hsep [ppr_lexpr arg, ptext SLIT(">-"), ppr_lexpr arrow]
+ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp True)
+ = hsep [ppr_lexpr arrow, ptext SLIT("-<<"), ppr_lexpr arg]
+ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp False)
+ = hsep [ppr_lexpr arg, ptext SLIT(">>-"), ppr_lexpr arrow]
+
+ppr_expr (HsArrForm (L _ (HsVar v)) (Just _) [arg1, arg2])
+ = sep [pprCmdArg (unLoc arg1), hsep [pprInfix v, pprCmdArg (unLoc arg2)]]
+ppr_expr (HsArrForm op _ args)
+ = hang (ptext SLIT("(|") <> ppr_lexpr op)
+ 4 (sep (map (pprCmdArg.unLoc) args) <> ptext SLIT("|)"))
+
+pprCmdArg :: OutputableBndr id => HsCmdTop id -> SDoc
+pprCmdArg (HsCmdTop cmd@(L _ (HsArrForm _ Nothing [])) _ _ _)
+ = ppr_lexpr cmd
+pprCmdArg (HsCmdTop cmd _ _ _)
+ = parens (ppr_lexpr cmd)
+
+-- Put a var in backquotes if it's not an operator already
+pprInfix :: Outputable name => name -> SDoc
+pprInfix v | isOperator ppr_v = ppr_v
+ | otherwise = char '`' <> ppr_v <> char '`'
+ where
+ ppr_v = ppr v
-- add parallel array brackets around a document
--
Parenthesize unless very simple:
\begin{code}
-pprParendExpr :: OutputableBndr id => HsExpr id -> SDoc
-
+pprParendExpr :: OutputableBndr id => LHsExpr id -> SDoc
pprParendExpr expr
= let
- pp_as_was = pprExpr expr
+ pp_as_was = ppr_lexpr expr
+ -- Using ppr_expr here avoids the call to 'deeper'
+ -- Not sure if that's always right.
in
- case expr of
- HsLit l -> ppr l
- HsOverLit l -> ppr l
-
- HsVar _ -> pp_as_was
- HsIPVar _ -> pp_as_was
- ExplicitList _ _ -> pp_as_was
- ExplicitPArr _ _ -> pp_as_was
- ExplicitTuple _ _ -> pp_as_was
- HsPar _ -> pp_as_was
-
- _ -> parens pp_as_was
+ case unLoc expr of
+ HsLit l -> ppr l
+ HsOverLit l -> ppr l
+
+ HsVar _ -> pp_as_was
+ HsIPVar _ -> pp_as_was
+ ExplicitList _ _ -> pp_as_was
+ ExplicitPArr _ _ -> pp_as_was
+ ExplicitTuple _ _ -> pp_as_was
+ HsPar _ -> pp_as_was
+ HsBracket _ -> pp_as_was
+ HsBracketOut _ [] -> pp_as_was
+
+ _ -> parens pp_as_was
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Commands (in arrow abstractions)}
+%* *
+%************************************************************************
+
+We re-use HsExpr to represent these.
+
+\begin{code}
+type HsCmd id = HsExpr id
+
+type LHsCmd id = LHsExpr id
+
+data HsArrAppType = HsHigherOrderApp | HsFirstOrderApp
+\end{code}
+
+The legal constructors for commands are:
+
+ = HsArrApp ... -- as above
+
+ | HsArrForm ... -- as above
+
+ | HsApp (HsCmd id)
+ (HsExpr id)
+
+ | HsLam (Match id) -- kappa
+
+ -- the renamer turns this one into HsArrForm
+ | OpApp (HsExpr id) -- left operand
+ (HsCmd id) -- operator
+ Fixity -- Renamer adds fixity; bottom until then
+ (HsCmd id) -- right operand
+
+ | HsPar (HsCmd id) -- parenthesised command
+
+ | HsCase (HsExpr id)
+ [Match id] -- bodies are HsCmd's
+ SrcLoc
+
+ | HsIf (HsExpr id) -- predicate
+ (HsCmd id) -- then part
+ (HsCmd id) -- else part
+ SrcLoc
+
+ | HsLet (HsLocalBinds id) -- let(rec)
+ (HsCmd id)
+
+ | HsDo (HsStmtContext Name) -- The parameterisation is unimportant
+ -- because in this context we never use
+ -- the PatGuard or ParStmt variant
+ [Stmt id] -- HsExpr's are really HsCmd's
+ PostTcType -- Type of the whole expression
+ SrcLoc
+
+Top-level command, introducing a new arrow.
+This may occur inside a proc (where the stack is empty) or as an
+argument of a command-forming operator.
+
+\begin{code}
+type LHsCmdTop id = Located (HsCmdTop id)
+
+data HsCmdTop id
+ = HsCmdTop (LHsCmd id)
+ [PostTcType] -- types of inputs on the command's stack
+ PostTcType -- return type of the command
+ (SyntaxTable id)
+ -- after type checking:
+ -- names used in the command's desugaring
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-type HsRecordBinds id = [(id, HsExpr id)]
+type HsRecordBinds id = [(Located id, LHsExpr id)]
recBindFields :: HsRecordBinds id -> [id]
-recBindFields rbinds = [field | (field,_) <- rbinds]
+recBindFields rbinds = [unLoc field | (field,_) <- rbinds]
pp_rbinds :: OutputableBndr id => SDoc -> HsRecordBinds id -> SDoc
-
pp_rbinds thing rbinds
= hang thing
4 (braces (sep (punctuate comma (map (pp_rbind) rbinds))))
where
- pp_rbind (v, e) = hsep [pprBndr LetBind v, char '=', ppr e]
+ pp_rbind (v, e) = hsep [pprBndr LetBind (unLoc v), char '=', ppr e]
\end{code}
patterns in each equation.
\begin{code}
+data MatchGroup id
+ = MatchGroup
+ [LMatch id] -- The alternatives
+ PostTcType -- The type is the type of the entire group
+ -- t1 -> ... -> tn -> tr
+ -- where there are n patterns
+
+type LMatch id = Located (Match id)
+
data Match id
= Match
- [Pat id] -- The patterns
- (Maybe (HsType id)) -- A type signature for the result of the match
+ [LPat id] -- The patterns
+ (Maybe (LHsType id)) -- A type signature for the result of the match
-- Nothing after typechecking
-
(GRHSs id)
--- GRHSs are used both for pattern bindings and for Matches
-data GRHSs id
- = GRHSs [GRHS id] -- Guarded RHSs
- (HsBinds id) -- The where clause
- PostTcType -- Type of RHS (after type checking)
-
-data GRHS id
- = GRHS [Stmt id] -- The RHS is the final ResultStmt
- SrcLoc
+matchGroupArity :: MatchGroup id -> Arity
+matchGroupArity (MatchGroup (match:matches) _)
+ = ASSERT( all ((== n_pats) . length . hsLMatchPats) matches )
+ -- Assertion just checks that all the matches have the same number of pats
+ n_pats
+ where
+ n_pats = length (hsLMatchPats match)
-mkSimpleMatch :: [Pat id] -> HsExpr id -> Type -> SrcLoc -> Match id
-mkSimpleMatch pats rhs rhs_ty locn
- = Match pats Nothing (GRHSs (unguardedRHS rhs locn) EmptyBinds rhs_ty)
+hsLMatchPats :: LMatch id -> [LPat id]
+hsLMatchPats (L _ (Match pats _ _)) = pats
-unguardedRHS :: HsExpr id -> SrcLoc -> [GRHS id]
-unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
-\end{code}
+-- GRHSs are used both for pattern bindings and for Matches
+data GRHSs id
+ = GRHSs [LGRHS id] -- Guarded RHSs
+ (HsLocalBinds id) -- The where clause
-@getMatchLoc@ takes a @Match@ and returns the
-source-location gotten from the GRHS inside.
-THis is something of a nuisance, but no more.
+type LGRHS id = Located (GRHS id)
-\begin{code}
-getMatchLoc :: Match id -> SrcLoc
-getMatchLoc (Match _ _ (GRHSs (GRHS _ loc : _) _ _)) = loc
+data GRHS id = GRHS [LStmt id] -- Guards
+ (LHsExpr id) -- Right hand side
\end{code}
We know the list must have at least one @Match@ in it.
\begin{code}
-pprMatches :: (OutputableBndr id) => HsMatchContext id -> [Match id] -> SDoc
-pprMatches ctxt matches = vcat (map (pprMatch ctxt) matches)
+pprMatches :: (OutputableBndr id) => HsMatchContext id -> MatchGroup id -> SDoc
+pprMatches ctxt (MatchGroup matches _) = vcat (map (pprMatch ctxt) (map unLoc matches))
-- Exported to HsBinds, which can't see the defn of HsMatchContext
-pprFunBind :: (OutputableBndr id) => id -> [Match id] -> SDoc
+pprFunBind :: (OutputableBndr id) => id -> MatchGroup id -> SDoc
pprFunBind fun matches = pprMatches (FunRhs fun) matches
-- Exported to HsBinds, which can't see the defn of HsMatchContext
-pprPatBind :: (OutputableBndr id)
- => Pat id -> GRHSs id -> SDoc
+pprPatBind :: (OutputableBndr bndr, OutputableBndr id)
+ => LPat bndr -> GRHSs id -> SDoc
pprPatBind pat grhss = sep [ppr pat, nest 4 (pprGRHSs PatBindRhs grhss)]
pprMatch :: OutputableBndr id => HsMatchContext id -> Match id -> SDoc
pprMatch ctxt (Match pats maybe_ty grhss)
= pp_name ctxt <+> sep [sep (map ppr pats),
- ppr_maybe_ty,
+ ppr_maybe_ty,
nest 2 (pprGRHSs ctxt grhss)]
where
pp_name (FunRhs fun) = ppr fun -- Not pprBndr; the AbsBinds will
pprGRHSs :: OutputableBndr id => HsMatchContext id -> GRHSs id -> SDoc
-pprGRHSs ctxt (GRHSs grhss binds ty)
- = vcat (map (pprGRHS ctxt) grhss)
+pprGRHSs ctxt (GRHSs grhss binds)
+ = vcat (map (pprGRHS ctxt . unLoc) grhss)
$$
- (if nullBinds binds then empty
- else text "where" $$ nest 4 (pprDeeper (ppr binds)))
-
+ (if isEmptyLocalBinds binds then empty
+ else text "where" $$ nest 4 (pprBinds binds))
pprGRHS :: OutputableBndr id => HsMatchContext id -> GRHS id -> SDoc
-pprGRHS ctxt (GRHS [ResultStmt expr _] locn)
+pprGRHS ctxt (GRHS [] expr)
= pp_rhs ctxt expr
-pprGRHS ctxt (GRHS guarded locn)
+pprGRHS ctxt (GRHS guards expr)
= sep [char '|' <+> interpp'SP guards, pp_rhs ctxt expr]
- where
- ResultStmt expr _ = last guarded -- Last stmt should be a ResultStmt for guards
- guards = init guarded
pp_rhs ctxt rhs = matchSeparator ctxt <+> pprDeeper (ppr rhs)
\end{code}
-
-
%************************************************************************
%* *
\subsection{Do stmts and list comprehensions}
%************************************************************************
\begin{code}
+type LStmt id = Located (Stmt id)
+
+-- The SyntaxExprs in here are used *only* for do-notation, which
+-- has rebindable syntax. Otherwise they are unused.
data Stmt id
- = BindStmt (Pat id) (HsExpr id) SrcLoc
- | LetStmt (HsBinds id)
- | ResultStmt (HsExpr id) SrcLoc -- See notes that follow
- | ExprStmt (HsExpr id) PostTcType SrcLoc -- See notes that follow
- -- The type is the *element type* of the expression
+ = BindStmt (LPat id)
+ (LHsExpr id)
+ (SyntaxExpr id) -- The (>>=) operator
+ (SyntaxExpr id) -- The fail operator
+ -- The fail operator is noSyntaxExpr
+ -- if the pattern match can't fail
+
+ | ExprStmt (LHsExpr id)
+ (SyntaxExpr id) -- The (>>) operator
+ PostTcType -- Element type of the RHS (used for arrows)
+
+ | LetStmt (HsLocalBinds id)
-- ParStmts only occur in a list comprehension
- | ParStmt [[Stmt id]] -- List comp only: parallel set of quals
- | ParStmtOut [([id], [Stmt id])] -- PLC after renaming; the ids are the binders
- -- bound by the stmts
-
- -- mdo-notation (only exists after renamer)
- -- The ids are a subset of the variables bound by the stmts that
- -- either (a) are used before they are bound in the stmts
- -- or (b) are used in stmts that follow the RecStmt
- | RecStmt [id]
- [Stmt id]
- [HsExpr id] -- Post type-checking only; these expressions correspond
- -- 1-to-1 with the [id], and are the expresions that should
- -- be returned by the recursion. They may not quite be the
- -- Ids themselves, because the Id may be polymorphic, but
- -- the returned thing has to be monomorphic.
+ | ParStmt [([LStmt id], [id])] -- After renaming, the ids are the binders
+ -- bound by the stmts and used subsequently
+
+ -- Recursive statement (see Note [RecStmt] below)
+ | RecStmt [LStmt id]
+ --- The next two fields are only valid after renaming
+ [id] -- The ids are a subset of the variables bound by the stmts
+ -- that are used in stmts that follow the RecStmt
+
+ [id] -- Ditto, but these variables are the "recursive" ones, that
+ -- are used before they are bound in the stmts of the RecStmt
+ -- From a type-checking point of view, these ones have to be monomorphic
+
+ --- These fields are only valid after typechecking
+ [PostTcExpr] -- These expressions correspond
+ -- 1-to-1 with the "recursive" [id], and are the expresions that
+ -- should be returned by the recursion. They may not quite be the
+ -- Ids themselves, because the Id may be *polymorphic*, but
+ -- the returned thing has to be *monomorphic*.
+ (DictBinds id) -- Method bindings of Ids bound by the RecStmt,
+ -- and used afterwards
\end{code}
-ExprStmts and ResultStmts are a bit tricky, because what they mean
+ExprStmts are a bit tricky, because what they mean
depends on the context. Consider the following contexts:
A do expression of type (m res_ty)
E :: m any_ty
Translation: E >> ...
- * ResultStmt E: do { ....; E }
- E :: m res_ty
- Translation: E
-
A list comprehensions of type [elt_ty]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ExprStmt E Bool: [ .. | .... E ]
E :: Bool
Translation: if E then fail else ...
- * ResultStmt E: [ E | ... ]
- E :: elt_ty
- Translation: return E
-
A guard list, guarding a RHS of type rhs_ty
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ExprStmt E Bool: f x | ..., E, ... = ...rhs...
E :: Bool
Translation: if E then fail else ...
- * ResultStmt E: f x | ...guards... = E
- E :: rhs_ty
- Translation: E
-
Array comprehensions are handled like list comprehensions -=chak
-\begin{code}
-consLetStmt :: HsBinds id -> [Stmt id] -> [Stmt id]
-consLetStmt EmptyBinds stmts = stmts
-consLetStmt binds stmts = LetStmt binds : stmts
-\end{code}
+Note [RecStmt]
+~~~~~~~~~~~~~~
+Example:
+ HsDo [ BindStmt x ex
+
+ , RecStmt [a::forall a. a -> a, b]
+ [a::Int -> Int, c]
+ [ BindStmt b (return x)
+ , LetStmt a = ea
+ , BindStmt c ec ]
+
+ , return (a b) ]
+
+Here, the RecStmt binds a,b,c; but
+ - Only a,b are used in the stmts *following* the RecStmt,
+ This 'a' is *polymorphic'
+ - Only a,c are used in the stmts *inside* the RecStmt
+ *before* their bindings
+ This 'a' is monomorphic
+
+Nota Bene: the two a's have different types, even though they
+have the same Name.
+
\begin{code}
instance OutputableBndr id => Outputable (Stmt id) where
ppr stmt = pprStmt stmt
-pprStmt (BindStmt pat expr _) = hsep [ppr pat, ptext SLIT("<-"), ppr expr]
-pprStmt (LetStmt binds) = hsep [ptext SLIT("let"), pprBinds binds]
-pprStmt (ExprStmt expr _ _) = ppr expr
-pprStmt (ResultStmt expr _) = ppr expr
-pprStmt (ParStmt stmtss)
- = hsep (map (\stmts -> ptext SLIT("| ") <> ppr stmts) stmtss)
-pprStmt (ParStmtOut stmtss)
- = hsep (map (\stmts -> ptext SLIT("| ") <> ppr stmts) stmtss)
-pprStmt (RecStmt _ segment _) = vcat (map ppr segment)
-
-pprDo :: OutputableBndr id => HsStmtContext any -> [Stmt id] -> SDoc
-pprDo DoExpr stmts = hang (ptext SLIT("do")) 2 (vcat (map ppr stmts))
-pprDo MDoExpr stmts = hang (ptext SLIT("mdo")) 3 (vcat (map ppr stmts))
-pprDo ListComp stmts = pprComp brackets stmts
-pprDo PArrComp stmts = pprComp pa_brackets stmts
-
-pprComp :: OutputableBndr id => (SDoc -> SDoc) -> [Stmt id] -> SDoc
-pprComp brack stmts = brack $
- hang (pprExpr expr <+> char '|')
- 4 (interpp'SP quals)
- where
- ResultStmt expr _ = last stmts -- Last stmt should
- quals = init stmts -- be an ResultStmt
+pprStmt (BindStmt pat expr _ _) = hsep [ppr pat, ptext SLIT("<-"), ppr expr]
+pprStmt (LetStmt binds) = hsep [ptext SLIT("let"), pprBinds binds]
+pprStmt (ExprStmt expr _ _) = ppr expr
+pprStmt (ParStmt stmtss) = hsep (map (\stmts -> ptext SLIT("| ") <> ppr stmts) stmtss)
+pprStmt (RecStmt segment _ _ _ _) = ptext SLIT("rec") <+> braces (vcat (map ppr segment))
+
+pprDo :: OutputableBndr id => HsStmtContext any -> [LStmt id] -> LHsExpr id -> SDoc
+pprDo DoExpr stmts body = hang (ptext SLIT("do")) 2 (vcat (map ppr stmts) $$ ppr body)
+pprDo (MDoExpr _) stmts body = hang (ptext SLIT("mdo")) 3 (vcat (map ppr stmts) $$ ppr body)
+pprDo ListComp stmts body = pprComp brackets stmts body
+pprDo PArrComp stmts body = pprComp pa_brackets stmts body
+
+pprComp :: OutputableBndr id => (SDoc -> SDoc) -> [LStmt id] -> LHsExpr id -> SDoc
+pprComp brack quals body
+ = brack $
+ hang (ppr body <+> char '|')
+ 4 (interpp'SP quals)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-data HsBracket id = ExpBr (HsExpr id)
- | PatBr (Pat id)
- | DecBr (HsGroup id)
- | TypBr (HsType id)
+data HsSplice id = HsSplice -- $z or $(f 4)
+ id -- The id is just a unique name to
+ (LHsExpr id) -- identify this splice point
+
+instance OutputableBndr id => Outputable (HsSplice id) where
+ ppr = pprSplice
+
+pprSplice :: OutputableBndr id => HsSplice id -> SDoc
+pprSplice (HsSplice n e) = char '$' <> brackets (ppr n) <> pprParendExpr e
+
+
+data HsBracket id = ExpBr (LHsExpr id) -- [| expr |]
+ | PatBr (LPat id) -- [p| pat |]
+ | DecBr (HsGroup id) -- [d| decls |]
+ | TypBr (LHsType id) -- [t| type |]
+ | VarBr id -- 'x, ''T
instance OutputableBndr id => Outputable (HsBracket id) where
ppr = pprHsBracket
pprHsBracket (PatBr p) = thBrackets (char 'p') (ppr p)
pprHsBracket (DecBr d) = thBrackets (char 'd') (ppr d)
pprHsBracket (TypBr t) = thBrackets (char 't') (ppr t)
-
+pprHsBracket (VarBr n) = char '\'' <> ppr n
+ -- Infelicity: can't show ' vs '', because
+ -- we can't ask n what its OccName is, because the
+ -- pretty-printer for HsExpr doesn't ask for NamedThings
+ -- But the pretty-printer for names will show the OccName class
thBrackets pp_kind pp_body = char '[' <> pp_kind <> char '|' <+>
pp_body <+> ptext SLIT("|]")
-
-data HsReify id = Reify ReifyFlavour id -- Pre typechecking
- | ReifyOut ReifyFlavour Name -- Post typechecking
- -- The Name could be the name of
- -- an Id, TyCon, or Class
-
-data ReifyFlavour = ReifyDecl | ReifyType | ReifyFixity
-
-instance Outputable id => Outputable (HsReify id) where
- ppr (Reify flavour id) = ppr flavour <+> ppr id
- ppr (ReifyOut flavour thing) = ppr flavour <+> ppr thing
-
-instance Outputable ReifyFlavour where
- ppr ReifyDecl = ptext SLIT("reifyDecl")
- ppr ReifyType = ptext SLIT("reifyType")
- ppr ReifyFixity = ptext SLIT("reifyFixity")
\end{code}
%************************************************************************
\begin{code}
data ArithSeqInfo id
- = From (HsExpr id)
- | FromThen (HsExpr id)
- (HsExpr id)
- | FromTo (HsExpr id)
- (HsExpr id)
- | FromThenTo (HsExpr id)
- (HsExpr id)
- (HsExpr id)
+ = From (LHsExpr id)
+ | FromThen (LHsExpr id)
+ (LHsExpr id)
+ | FromTo (LHsExpr id)
+ (LHsExpr id)
+ | FromThenTo (LHsExpr id)
+ (LHsExpr id)
+ (LHsExpr id)
\end{code}
\begin{code}
= FunRhs id -- Function binding for f
| CaseAlt -- Guard on a case alternative
| LambdaExpr -- Pattern of a lambda
+ | ProcExpr -- Pattern of a proc
| PatBindRhs -- Pattern binding
| RecUpd -- Record update [used only in DsExpr to tell matchWrapper
-- what sort of runtime error message to generate]
data HsStmtContext id
= ListComp
| DoExpr
- | MDoExpr -- Recursive do-expression
+ | MDoExpr PostTcTable -- Recursive do-expression
+ -- (tiresomely, it needs table
+ -- of its return/bind ops)
| PArrComp -- Parallel array comprehension
| PatGuard (HsMatchContext id) -- Pattern guard for specified thing
| ParStmtCtxt (HsStmtContext id) -- A branch of a parallel stmt
\begin{code}
isDoExpr :: HsStmtContext id -> Bool
-isDoExpr DoExpr = True
-isDoExpr MDoExpr = True
-isDoExpr other = False
+isDoExpr DoExpr = True
+isDoExpr (MDoExpr _) = True
+isDoExpr other = False
\end{code}
\begin{code}
matchSeparator (FunRhs _) = ptext SLIT("=")
matchSeparator CaseAlt = ptext SLIT("->")
matchSeparator LambdaExpr = ptext SLIT("->")
+matchSeparator ProcExpr = ptext SLIT("->")
matchSeparator PatBindRhs = ptext SLIT("=")
matchSeparator (StmtCtxt _) = ptext SLIT("<-")
matchSeparator RecUpd = panic "unused"
pprMatchContext RecUpd = ptext SLIT("a record-update construct")
pprMatchContext PatBindRhs = ptext SLIT("a pattern binding")
pprMatchContext LambdaExpr = ptext SLIT("a lambda abstraction")
+pprMatchContext ProcExpr = ptext SLIT("an arrow abstraction")
pprMatchContext (StmtCtxt ctxt) = ptext SLIT("a pattern binding in") $$ pprStmtContext ctxt
pprMatchRhsContext (FunRhs fun) = ptext SLIT("a right-hand side of function") <+> quotes (ppr fun)
pprMatchRhsContext CaseAlt = ptext SLIT("the body of a case alternative")
pprMatchRhsContext PatBindRhs = ptext SLIT("the right-hand side of a pattern binding")
pprMatchRhsContext LambdaExpr = ptext SLIT("the body of a lambda")
+pprMatchRhsContext ProcExpr = ptext SLIT("the body of a proc")
pprMatchRhsContext RecUpd = panic "pprMatchRhsContext"
pprStmtContext (ParStmtCtxt c) = sep [ptext SLIT("a parallel branch of"), pprStmtContext c]
pprStmtContext (PatGuard ctxt) = ptext SLIT("a pattern guard for") $$ pprMatchContext ctxt
pprStmtContext DoExpr = ptext SLIT("a 'do' expression")
-pprStmtContext MDoExpr = ptext SLIT("an 'mdo' expression")
+pprStmtContext (MDoExpr _) = ptext SLIT("an 'mdo' expression")
pprStmtContext ListComp = ptext SLIT("a list comprehension")
pprStmtContext PArrComp = ptext SLIT("an array comprehension")
matchContextErrString PatBindRhs = "pattern binding"
matchContextErrString RecUpd = "record update"
matchContextErrString LambdaExpr = "lambda"
+matchContextErrString ProcExpr = "proc"
matchContextErrString (StmtCtxt (ParStmtCtxt c)) = matchContextErrString (StmtCtxt c)
matchContextErrString (StmtCtxt (PatGuard _)) = "pattern guard"
matchContextErrString (StmtCtxt DoExpr) = "'do' expression"
-matchContextErrString (StmtCtxt MDoExpr) = "'mdo' expression"
+matchContextErrString (StmtCtxt (MDoExpr _)) = "'mdo' expression"
matchContextErrString (StmtCtxt ListComp) = "list comprehension"
matchContextErrString (StmtCtxt PArrComp) = "array comprehension"
\end{code}
projects / ghc-hetmet.git / blobdiff