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definition:
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binding2SMT :: Bool -> (Int,TAExpr) -> TransStateM SMT.Term
binding2SMT demanded (resvar,exp) =
case simpExpr exp of
AVar _ i -> return $ if resvar==i then true
else tvar resvar =% tvar i
ALit _ l -> return (tvar resvar =% lit2SMT l)
AComb rtype ct (qf,_) args -> do
(bs,nargs) <- normalizeArgs args
isStrict <- lift $ getOption optStrict
-- TODO: select from 'bindexps' only demanded argument positions
bindexps <- mapM (binding2SMT $ isPrimOp qf || isStrict) bs
comb2bool qf rtype ct nargs bs bindexps
ALet _ bs e -> do
bindexps <- mapM (binding2SMT False)
(map (\ ((i,_),ae) -> (i,ae)) bs)
bexp <- binding2SMT demanded (resvar,e)
return (tand (bindexps ++ [bexp]))
AOr _ e1 e2 -> do
bexp1 <- binding2SMT demanded (resvar,e1)
bexp2 <- binding2SMT demanded (resvar,e2)
return (tor [bexp1, bexp2])
ACase _ _ e brs -> do
freshvar <- getFreshVar
addVarTypes [(freshvar, annExpr e)]
argbexp <- binding2SMT demanded (freshvar,e)
bbrs <- mapM branch2bool (map (\b->(freshvar,b)) brs)
return (tand [argbexp, tor bbrs])
ATyped _ e _ -> binding2SMT demanded (resvar,e)
AFree _ _ _ -> error "Free variables not yet supported!"
where
comb2bool qf rtype ct nargs bs bindexps
| qf == pre "otherwise"
-- specific handling for the moment since the front end inserts it
-- as the last alternative of guarded rules...
= return (tvar resvar =% true)
| ct == ConsCall
= return (tand (bindexps ++
[tvar resvar =%
(SMT.TComb (cons2SMT (null nargs) False qf rtype)
(map arg2bool nargs))]))
| qf == pre "apply"
= -- cannot translate h.o. apply: ignore it
return true
| isPrimOp qf
= return (tand (bindexps ++
[tvar resvar =%
(SMT.TComb (cons2SMT True False qf rtype)
(map arg2bool nargs))]))
| otherwise -- non-primitive operation: add contract only if demanded
= do let targs = zip (map fst bs) (map annExpr nargs)
precond <- preCondExpOf qf targs
postcond <- postCondExpOf qf (targs ++ [(resvar,rtype)])
isCon <- lift $ getOption optConFail
return (tand (bindexps ++
if demanded && isCon
then [precond,postcond]
else []))
branch2bool (cvar, ABranch p e) = do
branchbexp <- binding2SMT demanded (resvar,e)
addVarTypes patvars
return (tand [ tvar cvar =% pat2SMT p, branchbexp])
where
patvars = if isConsPattern p
then patArgs p
else []
arg2bool e = case e of AVar _ i -> tvar i
ALit _ l -> lit2SMT l
_ -> error $ "Not normalized: " ++ show e
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documentation:
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---------------------------------------------------------------------------
-- Translates a FlatCurry expression to a Boolean formula representing
-- the binding of a variable (represented by its index in the first
-- component) to the translated expression (second component).
-- The translated expression is normalized when necessary.
-- For this purpose, a "fresh variable index" is passed as a state.
-- Moreover, the returned state contains also the types of all fresh variables.
-- If the first argument is `False`, the expression is not strictly demanded,
-- i.e., possible contracts of it (if it is a function call) are ignored.
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