#include "HsVersions.h"
-- friends:
-import HsBinds ( HsBinds(..), nullBinds )
-import HsTypes ( PostTcType )
-import HsLit ( HsLit, HsOverLit )
-import BasicTypes ( Fixity(..) )
-import HsTypes ( HsType )
-import HsImpExp ( isOperator )
+import HsDecls ( HsGroup )
+import HsPat ( LPat )
+import HsLit ( HsLit(..), HsOverLit )
+import HsTypes ( LHsType, PostTcType, SyntaxName )
+import HsImpExp ( isOperator, pprHsVar )
+import HsBinds ( HsBindGroup )
-- others:
+import Type ( Type, pprParendType )
+import Var ( TyVar, Id )
import Name ( Name )
-import ForeignCall ( Safety )
-import Outputable
-import PprType ( pprParendType )
-import Type ( Type )
-import Var ( TyVar )
import DataCon ( DataCon )
-import CStrings ( CLabelString, pprCLabelString )
-import BasicTypes ( Boxity, tupleParens )
-import SrcLoc ( SrcLoc )
+import BasicTypes ( IPName, Boxity, tupleParens, Fixity(..) )
+import SrcLoc ( Located(..), unLoc )
+import Outputable
+import FastString
\end{code}
+
%************************************************************************
%* *
\subsection{Expressions proper}
%************************************************************************
\begin{code}
-data HsExpr id pat
+type LHsExpr id = Located (HsExpr id)
+
+data HsExpr id
= HsVar id -- variable
- | HsIPVar id -- implicit parameter
+ | HsIPVar (IPName id) -- implicit parameter
| HsOverLit HsOverLit -- Overloaded literals; eliminated by type checker
| HsLit HsLit -- Simple (non-overloaded) literals
- | HsLam (Match id pat) -- lambda
- | HsApp (HsExpr id pat) -- application
- (HsExpr id pat)
+ | HsLam (LMatch id) -- lambda
+ | 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 pat) -- left operand
- (HsExpr id pat) -- operator
- Fixity -- Renamer adds fixity; bottom until then
- (HsExpr id pat) -- right operand
+ | OpApp (LHsExpr id) -- left operand
+ (LHsExpr id) -- operator
+ Fixity -- Renamer adds fixity; bottom until then
+ (LHsExpr id) -- right operand
-- We preserve prefix negation and parenthesis for the precedence parser.
-- They are eventually removed by the type checker.
- | NegApp (HsExpr id pat) -- negated expr
- Name -- Name of 'negate' (see RnEnv.lookupSyntaxName)
+ | NegApp (LHsExpr id) -- negated expr
+ SyntaxName -- Name of 'negate' (see RnEnv.lookupSyntaxName)
- | HsPar (HsExpr id pat) -- parenthesised expr
+ | HsPar (LHsExpr id) -- parenthesised expr
- | SectionL (HsExpr id pat) -- operand
- (HsExpr id pat) -- operator
- | SectionR (HsExpr id pat) -- operator
- (HsExpr id pat) -- operand
+ | SectionL (LHsExpr id) -- operand
+ (LHsExpr id) -- operator
+ | SectionR (LHsExpr id) -- operator
+ (LHsExpr id) -- operand
- | HsCase (HsExpr id pat)
- [Match id pat]
- SrcLoc
+ | HsCase (LHsExpr id)
+ [LMatch id]
- | HsIf (HsExpr id pat) -- predicate
- (HsExpr id pat) -- then part
- (HsExpr id pat) -- else part
- SrcLoc
-
- | HsLet (HsBinds id pat) -- let(rec)
- (HsExpr id pat)
+ | HsIf (LHsExpr id) -- predicate
+ (LHsExpr id) -- then part
+ (LHsExpr id) -- else part
- | HsWith (HsExpr id pat) -- implicit parameter binding
- [(id, HsExpr id pat)]
+ | HsLet [HsBindGroup id] -- let(rec)
+ (LHsExpr id)
- | HsDo HsDoContext
- [Stmt id pat] -- "do":one or more stmts
- SrcLoc
-
- | HsDoOut HsDoContext
- [Stmt id pat] -- "do":one or more stmts
- id -- id for return
- id -- id for >>=
- id -- id for fail
- Type -- Type of the whole expression
- SrcLoc
+ | HsDo (HsStmtContext Name) -- The parameterisation is unimportant
+ -- because in this context we never use
+ -- the PatGuard or ParStmt variant
+ [LStmt id] -- "do":one or more stmts
+ (ReboundNames id) -- Ids for [return,fail,>>=,>>]
+ PostTcType -- Type of the whole expression
| ExplicitList -- syntactic list
PostTcType -- Gives type of components of list
- [HsExpr id pat]
+ [LHsExpr id]
+
+ | ExplicitPArr -- syntactic parallel array: [:e1, ..., en:]
+ PostTcType -- type of elements of the parallel array
+ [LHsExpr id]
| ExplicitTuple -- tuple
- [HsExpr id pat]
+ [LHsExpr id]
-- NB: Unit is ExplicitTuple []
-- for tuples, we can get the types
-- direct from the components
-- Record construction
- | RecordCon id -- The constructor
- (HsRecordBinds id pat)
+ | RecordCon (Located id) -- The constructor
+ (HsRecordBinds id)
| RecordConOut DataCon
- (HsExpr id pat) -- Data con Id applied to type args
- (HsRecordBinds id pat)
+ (LHsExpr id) -- Data con Id applied to type args
+ (HsRecordBinds id)
-- Record update
- | RecordUpd (HsExpr id pat)
- (HsRecordBinds id pat)
+ | RecordUpd (LHsExpr id)
+ (HsRecordBinds id)
- | RecordUpdOut (HsExpr id pat) -- TRANSLATION
+ | RecordUpdOut (LHsExpr id) -- TRANSLATION
Type -- Type of *input* record
Type -- Type of *result* record (may differ from
-- type of input record)
- [id] -- Dicts needed for construction
- (HsRecordBinds id pat)
+ (HsRecordBinds id)
| ExprWithTySig -- signature binding
- (HsExpr id pat)
- (HsType id)
+ (LHsExpr id)
+ (LHsType id)
| ArithSeqIn -- arithmetic sequence
- (ArithSeqInfo id pat)
+ (ArithSeqInfo id)
| ArithSeqOut
- (HsExpr id pat) -- (typechecked, of course)
- (ArithSeqInfo id pat)
-
- | HsCCall CLabelString -- call into the C world; string is
- [HsExpr id pat] -- 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
-
- | HsSCC FAST_STRING -- "set cost centre" (_scc_) annotation
- (HsExpr id pat) -- expr whose cost is to be measured
-
+ (LHsExpr id) -- (typechecked, of course)
+ (ArithSeqInfo id)
+ | PArrSeqIn -- arith. sequence for parallel array
+ (ArithSeqInfo id) -- [:e1..e2:] or [:e1, e2..e3:]
+ | PArrSeqOut
+ (LHsExpr id) -- (typechecked, of course)
+ (ArithSeqInfo id)
+
+ | HsSCC FastString -- "set cost centre" (_scc_) annotation
+ (LHsExpr id) -- expr whose cost is to be measured
+
+ | HsCoreAnn FastString -- hdaume: core annotation
+ (LHsExpr id)
+
+ -----------------------------------------------------------
+ -- MetaHaskell Extensions
+ | 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 (LHsExpr id) -- $z or $(f 4)
+ -- The id is just a unique name to
+ -- identify this splice point
+
+ -----------------------------------------------------------
+ -- 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}
+
These constructors only appear temporarily in the parser.
The renamer translates them into the Right Thing.
\begin{code}
| EWildPat -- wildcard
- | EAsPat id -- as pattern
- (HsExpr id pat)
+ | EAsPat (Located id) -- as pattern
+ (LHsExpr id)
- | ELazyPat (HsExpr id pat) -- ~ 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 pat)
+ (LHsExpr id)
| TyApp -- TRANSLATION
- (HsExpr id pat) -- generated by Spec
+ (LHsExpr id) -- generated by Spec
[Type]
-- DictLam and DictApp are "inverses"
| DictLam
[id]
- (HsExpr id pat)
+ (LHsExpr id)
| DictApp
- (HsExpr id pat)
+ (LHsExpr id)
[id]
-type HsRecordBinds id pat
- = [(id, HsExpr id pat, Bool)]
- -- True <=> source code used "punning",
- -- i.e. {op1, op2} rather than {op1=e1, op2=e2}
+type PendingSplice = (Name, LHsExpr Id) -- Typechecked splices, waiting to be
+ -- pasted back in by the desugarer
+\end{code}
+
+Table of bindings of names used in rebindable syntax.
+This gets filled in by the renamer.
+
+\begin{code}
+type ReboundNames id = [(Name, LHsExpr id)]
+-- * Before the renamer, this list is empty
+--
+-- * 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
\end{code}
A @Dictionary@, unless of length 0 or 1, becomes a tuple. A
\end{verbatim}
\begin{code}
-instance (Outputable id, Outputable pat) =>
- Outputable (HsExpr id pat) where
+instance OutputableBndr id => Outputable (HsExpr id) where
ppr expr = pprExpr expr
\end{code}
\begin{code}
-pprExpr :: (Outputable id, Outputable pat)
- => HsExpr id pat -> SDoc
+pprExpr :: OutputableBndr id => HsExpr id -> SDoc
+
+pprExpr e = pprDeeper (ppr_expr e)
-pprExpr e = pprDeeper (ppr_expr e)
-pprBinds b = pprDeeper (ppr b)
+pprBinds :: OutputableBndr id => [HsBindGroup id] -> SDoc
+pprBinds b = pprDeeper (vcat (map ppr b))
-ppr_expr (HsVar v)
- -- Put it in parens if it's an operator
- | isOperator v = parens (ppr v)
- | otherwise = ppr v
+ppr_lexpr :: OutputableBndr id => LHsExpr id -> SDoc
+ppr_lexpr e = ppr_expr (unLoc e)
-ppr_expr (HsIPVar v) = char '?' <> ppr v
+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)
- = hsep [char '\\', nest 2 (pprMatch LambdaExpr match)]
+ppr_expr (HsLam match) = pprMatch LambdaExpr (unLoc 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
- pp_v_op | isOperator 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_infixly v = parens (sep [pp_expr, ppr v])
ppr_expr (SectionR op expr)
- = case op of
+ = case unLoc op of
HsVar v -> pp_infixly v
_ -> pp_prefixly
where
pp_infixly v
= parens (sep [ppr v, pp_expr])
-ppr_expr (HsCase expr matches _)
- = sep [ sep [ptext SLIT("case"), nest 4 (pprExpr expr), ptext SLIT("of")],
+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 (HsWith expr binds)
- = hsep [ppr expr, ptext SLIT("with"), ppr binds]
-
-ppr_expr (HsDo do_or_list_comp stmts _) = pprDo do_or_list_comp stmts
-ppr_expr (HsDoOut do_or_list_comp stmts _ _ _ _ _) = pprDo do_or_list_comp stmts
+ppr_expr (HsDo do_or_list_comp stmts _ _) = pprDo do_or_list_comp stmts
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_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)
= pp_rbinds (ppr con_id) rbinds
ppr_expr (RecordUpd aexp rbinds)
= pp_rbinds (pprParendExpr aexp) rbinds
-ppr_expr (RecordUpdOut aexp _ _ _ rbinds)
+ppr_expr (RecordUpdOut 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 (ArithSeqIn 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 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 (ptext lbl), pprParendExpr expr ]
+ = sep [ ptext SLIT("_scc_") <+> doubleQuotes (ftext lbl), pprParendExpr expr ]
ppr_expr (TyLam tyvars expr)
- = hang (hsep [ptext SLIT("/\\"), interppSP tyvars, ptext SLIT("->")])
- 4 (ppr_expr expr)
+ = hang (hsep [ptext SLIT("/\\"),
+ hsep (map (pprBndr LambdaBind) tyvars),
+ ptext SLIT("->")])
+ 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-}"), interppSP dictvars, ptext SLIT("->")])
- 4 (ppr_expr expr)
+ = hang (hsep [ptext SLIT("\\{-dict-}"),
+ hsep (map (pprBndr LambdaBind) dictvars),
+ ptext SLIT("->")])
+ 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 (HsType id) = ppr id
-
+
+ppr_expr (HsSplice n e) = char '$' <> brackets (ppr n) <> pprParendExpr e
+ppr_expr (HsBracket b) = ppr b
+ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("where") <+> 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
+--
+pa_brackets :: SDoc -> SDoc
+pa_brackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]")
\end{code}
Parenthesize unless very simple:
\begin{code}
-pprParendExpr :: (Outputable id, Outputable pat)
- => HsExpr id pat -> 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
+ 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
+
+ _ -> parens pp_as_was
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Commands (in arrow abstractions)}
+%* *
+%************************************************************************
- HsVar _ -> pp_as_was
- HsIPVar _ -> pp_as_was
- ExplicitList _ _ -> pp_as_was
- ExplicitTuple _ _ -> pp_as_was
- HsPar _ -> pp_as_was
+We re-use HsExpr to represent these.
- _ -> parens pp_as_was
+\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 (HsBinds 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
+ (ReboundNames id)
+ 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
+ (ReboundNames id)
+ -- after type checking:
+ -- names used in the command's desugaring
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-pp_rbinds :: (Outputable id, Outputable pat)
- => SDoc
- -> HsRecordBinds id pat -> SDoc
+type HsRecordBinds id = [(Located id, LHsExpr id)]
+
+recBindFields :: HsRecordBinds id -> [id]
+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, pun_flag)
- = getPprStyle $ \ sty ->
- if pun_flag && userStyle sty then
- ppr v
- else
- hsep [ppr 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 Match id pat
+type LMatch id = Located (Match id)
+
+data Match id
= Match
- [id] -- Tyvars wrt which this match is universally quantified
- -- empty after typechecking
- [pat] -- 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 pat)
+ (GRHSs id)
-- GRHSs are used both for pattern bindings and for Matches
-data GRHSs id pat
- = GRHSs [GRHS id pat] -- Guarded RHSs
- (HsBinds id pat) -- The where clause
+data GRHSs id
+ = GRHSs [LGRHS id] -- Guarded RHSs
+ [HsBindGroup id] -- The where clause
PostTcType -- Type of RHS (after type checking)
-data GRHS id pat
- = GRHS [Stmt id pat] -- The RHS is the final ResultStmt
- -- I considered using a RetunStmt, but
- -- it printed 'wrong' in error messages
- SrcLoc
-
-mkSimpleMatch :: [pat] -> HsExpr id pat -> Type -> SrcLoc -> Match id pat
-mkSimpleMatch pats rhs rhs_ty locn
- = Match [] pats Nothing (GRHSs (unguardedRHS rhs locn) EmptyBinds rhs_ty)
+type LGRHS id = Located (GRHS id)
-unguardedRHS :: HsExpr id pat -> SrcLoc -> [GRHS id pat]
-unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
-\end{code}
-
-@getMatchLoc@ takes a @Match@ and returns the
-source-location gotten from the GRHS inside.
-THis is something of a nuisance, but no more.
-
-\begin{code}
-getMatchLoc :: Match id pat -> SrcLoc
-getMatchLoc (Match _ _ _ (GRHSs (GRHS _ loc : _) _ _)) = loc
+data GRHS id
+ = GRHS [LStmt id] -- The RHS is the final ResultStmt
\end{code}
We know the list must have at least one @Match@ in it.
\begin{code}
-pprMatches :: (Outputable id, Outputable pat)
- => HsMatchContext id -> [Match id pat] -> SDoc
-pprMatches ctxt matches = vcat (map (pprMatch ctxt) matches)
+pprMatches :: (OutputableBndr id) => HsMatchContext id -> [LMatch id] -> SDoc
+pprMatches ctxt matches = vcat (map (pprMatch ctxt) (map unLoc matches))
-- Exported to HsBinds, which can't see the defn of HsMatchContext
-pprFunBind :: (Outputable id, Outputable pat)
- => id -> [Match id pat] -> SDoc
+pprFunBind :: (OutputableBndr id) => id -> [LMatch id] -> SDoc
pprFunBind fun matches = pprMatches (FunRhs fun) matches
-- Exported to HsBinds, which can't see the defn of HsMatchContext
-pprPatBind :: (Outputable id, Outputable pat)
- => pat -> GRHSs id pat -> SDoc
+pprPatBind :: (OutputableBndr id)
+ => LPat id -> GRHSs id -> SDoc
pprPatBind pat grhss = sep [ppr pat, nest 4 (pprGRHSs PatBindRhs grhss)]
-pprMatch :: (Outputable id, Outputable pat)
- => HsMatchContext id -> Match id pat -> SDoc
-pprMatch ctxt (Match _ pats maybe_ty 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,
nest 2 (pprGRHSs ctxt grhss)]
where
- pp_name (FunRhs fun) = ppr fun
+ pp_name (FunRhs fun) = ppr fun -- Not pprBndr; the AbsBinds will
+ -- have printed the signature
+ pp_name LambdaExpr = char '\\'
pp_name other = empty
+
ppr_maybe_ty = case maybe_ty of
Just ty -> dcolon <+> ppr ty
Nothing -> empty
-pprGRHSs :: (Outputable id, Outputable pat)
- => HsMatchContext id -> GRHSs id pat -> SDoc
+pprGRHSs :: OutputableBndr id => HsMatchContext id -> GRHSs id -> SDoc
pprGRHSs ctxt (GRHSs grhss binds ty)
- = vcat (map (pprGRHS ctxt) grhss)
+ = vcat (map (pprGRHS ctxt . unLoc) grhss)
$$
- (if nullBinds binds then empty
- else text "where" $$ nest 4 (pprDeeper (ppr binds)))
-
+ (if null binds then empty
+ else text "where" $$ nest 4 (pprBinds binds))
-pprGRHS :: (Outputable id, Outputable pat)
- => HsMatchContext id -> GRHS id pat -> SDoc
+pprGRHS :: OutputableBndr id => HsMatchContext id -> GRHS id -> SDoc
-pprGRHS ctxt (GRHS [ResultStmt expr _] locn)
+pprGRHS ctxt (GRHS [L _ (ResultStmt expr)])
= pp_rhs ctxt expr
-pprGRHS ctxt (GRHS guarded locn)
+pprGRHS ctxt (GRHS guarded)
= 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
+ ResultStmt expr = unLoc (last guarded)
+ -- Last stmt should be a ResultStmt for guards
+ guards = init guarded
-pp_rhs ctxt rhs = ptext (matchSeparator ctxt) <+> pprDeeper (ppr rhs)
+pp_rhs ctxt rhs = matchSeparator ctxt <+> pprDeeper (ppr rhs)
\end{code}
-
-
%************************************************************************
%* *
\subsection{Do stmts and list comprehensions}
%************************************************************************
\begin{code}
-data Stmt id pat
- = BindStmt pat (HsExpr id pat) SrcLoc
- | LetStmt (HsBinds id pat)
- | ResultStmt (HsExpr id pat) SrcLoc -- See notes that follow
- | ExprStmt (HsExpr id pat) PostTcType SrcLoc -- See notes that follow
+type LStmt id = Located (Stmt id)
+
+data Stmt id
+ = BindStmt (LPat id) (LHsExpr id)
+ | LetStmt [HsBindGroup id]
+ | ResultStmt (LHsExpr id) -- See notes that follow
+ | ExprStmt (LHsExpr id) PostTcType -- See notes that follow
-- The type is the *element type* of the expression
- | ParStmt [[Stmt id pat]] -- List comp only: parallel set of quals
- | ParStmtOut [([id], [Stmt id pat])] -- PLC after renaming; the ids are the binders
- -- bound by the stmts
+
+ -- ParStmts only occur in a list comprehension
+ | ParStmt [([LStmt id], [id])] -- After remaing, the ids are the binders
+ -- bound by the stmts and used subsequently
+
+ -- Recursive statement
+ | 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
+
+ --- This field is only valid after typechecking
+ [LHsExpr id] -- 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*.
\end{code}
ExprStmts and ResultStmts are a bit tricky, because what they mean
E :: rhs_ty
Translation: E
+Array comprehensions are handled like list comprehensions -=chak
\begin{code}
-consLetStmt :: HsBinds id pat -> [Stmt id pat] -> [Stmt id pat]
-consLetStmt EmptyBinds stmts = stmts
-consLetStmt binds stmts = LetStmt binds : stmts
-\end{code}
-
-\begin{code}
-instance (Outputable id, Outputable pat) =>
- Outputable (Stmt id pat) where
+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 (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 (RecStmt segment _ _ _) = ptext SLIT("rec") <+> braces (vcat (map ppr segment))
-pprDo :: (Outputable id, Outputable pat) => HsDoContext -> [Stmt id pat] -> SDoc
+pprDo :: OutputableBndr id => HsStmtContext any -> [LStmt id] -> SDoc
pprDo DoExpr stmts = hang (ptext SLIT("do")) 2 (vcat (map ppr stmts))
-pprDo ListComp stmts = brackets $
- hang (pprExpr expr <+> char '|')
- 4 (interpp'SP quals)
- where
- ResultStmt expr _ = last stmts -- Last stmt should
- quals = init stmts -- be an ResultStmt
+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) -> [LStmt id] -> SDoc
+pprComp brack stmts
+ = brack $
+ hang (ppr expr <+> char '|')
+ 4 (interpp'SP quals)
+ where
+ ResultStmt expr = unLoc (last stmts) -- Last stmt should
+ quals = init stmts -- be an ResultStmt
+\end{code}
+
+%************************************************************************
+%* *
+ Template Haskell quotation brackets
+%* *
+%************************************************************************
+
+\begin{code}
+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 (ExpBr e) = thBrackets empty (ppr e)
+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("|]")
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-data ArithSeqInfo id pat
- = From (HsExpr id pat)
- | FromThen (HsExpr id pat)
- (HsExpr id pat)
- | FromTo (HsExpr id pat)
- (HsExpr id pat)
- | FromThenTo (HsExpr id pat)
- (HsExpr id pat)
- (HsExpr id pat)
+data ArithSeqInfo 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}
-instance (Outputable id, Outputable pat) =>
- Outputable (ArithSeqInfo id pat) where
+instance OutputableBndr id => Outputable (ArithSeqInfo id) where
ppr (From e1) = hcat [ppr e1, pp_dotdot]
ppr (FromThen e1 e2) = hcat [ppr e1, comma, space, ppr e2, pp_dotdot]
ppr (FromTo e1 e3) = hcat [ppr e1, pp_dotdot, ppr e3]
%************************************************************************
\begin{code}
-data HsMatchContext id -- Context of a Match or Stmt
- = DoCtxt HsDoContext -- Do-stmt or list comprehension
- | FunRhs id -- Function binding for f
- | CaseAlt -- Guard on a case alternative
- | LambdaExpr -- Lambda
- | PatBindRhs -- Pattern binding
- | RecUpd -- Record update
+data HsMatchContext id -- Context of a Match
+ = 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]
+ | StmtCtxt (HsStmtContext id) -- Pattern of a do-stmt or list comprehension
deriving ()
-data HsDoContext = ListComp | DoExpr
+data HsStmtContext id
+ = ListComp
+ | DoExpr
+ | MDoExpr -- Recursive do-expression
+ | PArrComp -- Parallel array comprehension
+ | PatGuard (HsMatchContext id) -- Pattern guard for specified thing
+ | ParStmtCtxt (HsStmtContext id) -- A branch of a parallel stmt
\end{code}
\begin{code}
-isDoExpr (DoCtxt DoExpr) = True
-isDoExpr other = False
+isDoExpr :: HsStmtContext id -> Bool
+isDoExpr DoExpr = True
+isDoExpr MDoExpr = True
+isDoExpr other = False
\end{code}
\begin{code}
-matchSeparator (FunRhs _) = SLIT("=")
-matchSeparator CaseAlt = SLIT("->")
-matchSeparator LambdaExpr = SLIT("->")
-matchSeparator PatBindRhs = SLIT("=")
-matchSeparator (DoCtxt _) = SLIT("<-")
-matchSeparator RecUpd = panic "When is this used?"
+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"
\end{code}
\begin{code}
-pprMatchContext (FunRhs fun) = ptext SLIT("In the definition of") <+> quotes (ppr fun)
-pprMatchContext CaseAlt = ptext SLIT("In a case alternative")
-pprMatchContext RecUpd = ptext SLIT("In a record-update construct")
-pprMatchContext PatBindRhs = ptext SLIT("In a pattern binding")
-pprMatchContext LambdaExpr = ptext SLIT("In a lambda abstraction")
-pprMatchContext (DoCtxt DoExpr) = ptext SLIT("In a 'do' expression pattern binding")
-pprMatchContext (DoCtxt ListComp) = ptext SLIT("In a 'list comprehension' pattern binding")
+pprMatchContext (FunRhs fun) = ptext SLIT("the definition of") <+> quotes (ppr fun)
+pprMatchContext CaseAlt = ptext SLIT("a case alternative")
+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 ListComp = ptext SLIT("a list comprehension")
+pprStmtContext PArrComp = ptext SLIT("an array comprehension")
+
+-- Used for the result statement of comprehension
+-- e.g. the 'e' in [ e | ... ]
+-- or the 'r' in f x = r
+pprStmtResultContext (PatGuard ctxt) = pprMatchRhsContext ctxt
+pprStmtResultContext other = ptext SLIT("the result of") <+> pprStmtContext other
+
-- Used to generate the string for a *runtime* error message
-matchContextErrString (FunRhs fun) = "function " ++ showSDoc (ppr fun)
-matchContextErrString CaseAlt = "case"
-matchContextErrString PatBindRhs = "pattern binding"
-matchContextErrString RecUpd = "record update"
-matchContextErrString LambdaExpr = "lambda"
-matchContextErrString (DoCtxt DoExpr) = "'do' expression"
-matchContextErrString (DoCtxt ListComp) = "list comprehension"
+matchContextErrString (FunRhs fun) = "function " ++ showSDoc (ppr fun)
+matchContextErrString CaseAlt = "case"
+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 ListComp) = "list comprehension"
+matchContextErrString (StmtCtxt PArrComp) = "array comprehension"
\end{code}