#include "HsVersions.h"
-- friends:
-import HsDecls ( HsDecl )
+import HsDecls ( HsGroup )
import HsBinds ( HsBinds(..), nullBinds )
-import HsPat ( Pat )
-import HsLit ( HsLit, HsOverLit )
-import HsTypes ( HsType, PostTcType, SyntaxName )
+import HsPat ( Pat(..), HsConDetails(..) )
+import HsLit ( HsLit(..), HsOverLit )
+import HsTypes ( HsType, PostTcType, SyntaxName, placeHolderType )
import HsImpExp ( isOperator, pprHsVar )
-- others:
-import ForeignCall ( Safety )
-import PprType ( pprParendType )
-import Type ( Type )
+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 SrcLoc ( SrcLoc, generatedSrcLoc )
import Outputable
import FastString
\end{code}
+
+%************************************************************************
+%* *
+ Some useful helpers for constructing expressions
+%* *
+%************************************************************************
+
+\begin{code}
+mkHsApps f xs = foldl HsApp (HsVar f) xs
+mkHsVarApps f xs = foldl HsApp (HsVar f) (map HsVar xs)
+
+mkHsIntLit n = HsLit (HsInt n)
+mkHsString s = HsString (mkFastString s)
+
+mkConPat con vars = ConPatIn con (PrefixCon (map VarPat vars))
+mkNullaryConPat con = ConPatIn con (PrefixCon [])
+
+mkSimpleHsAlt :: Pat id -> HsExpr id -> Match id
+-- A simple lambda with a single pattern, no binds, no guards; pre-typechecking
+mkSimpleHsAlt pat expr
+ = mkSimpleMatch [pat] expr placeHolderType generatedSrcLoc
+
+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)
+
+unguardedRHS :: HsExpr id -> SrcLoc -> [GRHS id]
+unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
+
+glueBindsOnGRHSs :: HsBinds id -> GRHSs id -> GRHSs id
+glueBindsOnGRHSs EmptyBinds grhss = grhss
+glueBindsOnGRHSs binds1 (GRHSs grhss binds2 ty)
+ = GRHSs grhss (binds1 `ThenBinds` binds2) ty
+\end{code}
+
+
%************************************************************************
%* *
\subsection{Expressions proper}
| OpApp (HsExpr id) -- left operand
(HsExpr id) -- operator
- Fixity -- Renamer adds fixity; bottom until then
+ Fixity -- Renamer adds fixity; bottom until then
(HsExpr id) -- right operand
-- We preserve prefix negation and parenthesis for the precedence parser.
| HsLet (HsBinds id) -- let(rec)
(HsExpr id)
- | HsWith (HsExpr id) -- implicit parameter binding
- [(IPName id, HsExpr id)]
- Bool -- True <=> this was a 'with' binding
- -- (tmp, until 'with' is removed)
-
- | HsDo HsStmtContext
- [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
+ | 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
+ (ReboundNames id) -- Ids for [return,fail,>>=,>>]
+ PostTcType -- Type of the whole expression
SrcLoc
| ExplicitList -- syntactic list
(HsExpr id) -- (typechecked, of course)
(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
-
| HsSCC FastString -- "set cost centre" (_scc_) annotation
(HsExpr id) -- expr whose cost is to be measured
+
+ | HsCoreAnn FastString -- hdaume: core annotation
+ (HsExpr id)
+ -----------------------------------------------------------
-- MetaHaskell Extensions
- | HsBracket (HsBracket id)
+ | HsBracket (HsBracket id) SrcLoc
| 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 ) -- $z or $(f 4)
+ | HsSplice id (HsExpr id) SrcLoc -- $z or $(f 4)
-- The id is just a unique name to
-- identify this splice point
+
+ -----------------------------------------------------------
+ -- Arrow notation extension
+
+ | HsProc (Pat id) -- arrow abstraction, proc
+ (HsCmdTop id) -- body of the abstraction
+ -- always has an empty stack
+ SrcLoc
+
+ ---------------------------------------
+ -- The following are commands, not expressions proper
+
+ | HsArrApp -- Arrow tail, or arrow application (f -< arg)
+ (HsExpr id) -- arrow expression, f
+ (HsExpr 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)
+ SrcLoc
+
+ | HsArrForm -- Command formation, (| e cmd1 .. cmdn |)
+ (HsExpr 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
+ [HsCmdTop id] -- argument commands
+ SrcLoc
+
\end{code}
-- 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, HsExpr 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
@ClassDictLam dictvars methods expr@ is, therefore:
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 match
ppr_expr expr@(HsApp e1 e2)
= let (fun, args) = collect_args expr [] in
- (ppr_expr fun) <+> (sep (map ppr_expr args))
+ (ppr_expr fun) <+> (sep (map pprParendExpr args))
where
collect_args (HsApp fun arg) args = collect_args fun (arg:args)
collect_args fun args = (fun, args)
pp_e2 = pprParendExpr e2
pp_prefixly
- = hang (pprExpr op) 4 (sep [pp_e1, pp_e2])
+ = hang (ppr_expr 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
-- special case: let ... in let ...
ppr_expr (HsLet binds expr@(HsLet _ _))
= sep [hang (ptext SLIT("let")) 2 (hsep [pprBinds binds, ptext SLIT("in")]),
- pprExpr expr]
+ ppr_expr 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 is_with)
- = sep [hang (ptext SLIT("let")) 2 (pp_ipbinds binds),
- hang (ptext SLIT("in")) 2 (ppr expr)]
-
ppr_expr (HsDo do_or_list_comp stmts _ _ _) = pprDo do_or_list_comp stmts
ppr_expr (ExplicitList _ exprs)
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 ]
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 (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 (HsProc pat (HsCmdTop cmd _ _ _) _)
+ = hsep [ptext SLIT("proc"), ppr pat, ptext SLIT("->"), pprExpr cmd]
+
+ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp True _)
+ = hsep [ppr_expr arrow, ptext SLIT("-<"), ppr_expr arg]
+ppr_expr (HsArrApp arrow arg _ HsFirstOrderApp False _)
+ = hsep [ppr_expr arg, ptext SLIT(">-"), ppr_expr arrow]
+ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp True _)
+ = hsep [ppr_expr arrow, ptext SLIT("-<<"), ppr_expr arg]
+ppr_expr (HsArrApp arrow arg _ HsHigherOrderApp False _)
+ = hsep [ppr_expr arg, ptext SLIT(">>-"), ppr_expr arrow]
+
+ppr_expr (HsArrForm (HsVar v) (Just _) [arg1, arg2] _)
+ = sep [pprCmdArg arg1, hsep [pprInfix v, pprCmdArg arg2]]
+ppr_expr (HsArrForm op _ args _)
+ = hang (ptext SLIT("(|") <> ppr_expr op)
+ 4 (sep (map pprCmdArg args) <> ptext SLIT("|)"))
+
+pprCmdArg :: OutputableBndr id => HsCmdTop id -> SDoc
+pprCmdArg (HsCmdTop cmd@(HsArrForm _ Nothing [] _) _ _ _) = ppr_expr cmd
+pprCmdArg (HsCmdTop cmd _ _ _) = parens (ppr_expr 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
pprParendExpr expr
= let
- pp_as_was = pprExpr expr
+ pp_as_was = ppr_expr 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
+ 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)}
+%* *
+%************************************************************************
+
+We re-use HsExpr to represent these.
+
+\begin{code}
+type HsCmd id = HsExpr 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)
- HsVar _ -> pp_as_was
- HsIPVar _ -> pp_as_was
- ExplicitList _ _ -> pp_as_was
- ExplicitPArr _ _ -> pp_as_was
- ExplicitTuple _ _ -> pp_as_was
- HsPar _ -> pp_as_was
+ | 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
- _ -> parens pp_as_was
+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}
+data HsCmdTop id
+ = HsCmdTop (HsCmd 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}
%************************************************************************
pp_rbind (v, e) = hsep [pprBndr LetBind v, char '=', ppr e]
\end{code}
-\begin{code}
-pp_ipbinds :: OutputableBndr id => [(IPName id, HsExpr id)] -> SDoc
-pp_ipbinds pairs = hsep (punctuate semi (map pp_item pairs))
- where
- pp_item (id,rhs) = pprBndr LetBind id <+> equals <+> ppr_expr rhs
-\end{code}
%************************************************************************
data GRHS id
= GRHS [Stmt id] -- The RHS is the final ResultStmt
SrcLoc
-
-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)
-
-unguardedRHS :: HsExpr id -> SrcLoc -> [GRHS id]
-unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
\end{code}
@getMatchLoc@ takes a @Match@ and returns the
where
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
-- The type is the *element type* of the expression
-- 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]
+ | ParStmt [([Stmt id], [id])] -- After remaing, the ids are the binders
+ -- bound by the stmts and used subsequently
+
+ -- Recursive statement
+ | RecStmt [Stmt 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
+ [HsExpr 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
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 -> [Stmt id] -> SDoc
+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 :: 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
%************************************************************************
\begin{code}
-data HsBracket id = ExpBr (HsExpr id)
- | PatBr (Pat id)
- | DecBr [HsDecl id]
- | TypBr (HsType id)
+data HsBracket id = ExpBr (HsExpr id) -- [| expr |]
+ | PatBr (Pat id) -- [p| pat |]
+ | DecBr (HsGroup id) -- [d| decls |]
+ | TypBr (HsType 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') (vcat (map ppr d))
+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("|]")
%************************************************************************
\begin{code}
-data HsMatchContext id -- Context of a Match or Stmt
- = StmtCtxt HsStmtContext -- 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 HsStmtContext
- = ListComp
- | DoExpr
- | MDoExpr -- recursive do-expression
- | PArrComp -- parallel array comprehension
- | PatGuard -- Never occurs in an HsDo expression, of course
+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 :: HsStmtContext id -> Bool
isDoExpr DoExpr = True
isDoExpr MDoExpr = True
isDoExpr other = False
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 "When is this used?"
+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 (StmtCtxt ctxt) = pprStmtCtxt ctxt
-
-pprStmtCtxt PatGuard = ptext SLIT("In a pattern guard")
-pprStmtCtxt DoExpr = ptext SLIT("In a 'do' expression pattern binding")
-pprStmtCtxt MDoExpr = ptext SLIT("In an 'mdo' expression pattern binding")
-pprStmtCtxt ListComp = ptext SLIT("In a 'list comprehension' pattern binding")
-pprStmtCtxt PArrComp = ptext SLIT("In an 'array 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 (StmtCtxt PatGuard) = "pattern gaurd"
-matchContextErrString (StmtCtxt DoExpr) = "'do' expression"
-matchContextErrString (StmtCtxt MDoExpr) = "'mdo' expression"
-matchContextErrString (StmtCtxt ListComp) = "list comprehension"
-matchContextErrString (StmtCtxt PArrComp) = "array 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}
projects / ghc-hetmet.git / blobdiff