-(* calculate the free WeakVar's in a WeakExpr *)
-Fixpoint getWeakExprFreeVars (me:WeakExpr) : list WeakExprVar :=
- match me with
- | WELit _ => nil
- | WEVar cv => cv::nil
- | WECast e co => getWeakExprFreeVars e
- | WENote n e => getWeakExprFreeVars e
- | WETyApp e t => getWeakExprFreeVars e
- | WECoApp e co => getWeakExprFreeVars e
- | WEBrak ec e _ => getWeakExprFreeVars e
- | WEEsc ec e _ => getWeakExprFreeVars e
- | WELet cv e1 e2 => mergeDistinctLists (getWeakExprFreeVars e1) (removeFromDistinctList cv (getWeakExprFreeVars e2))
- | WEApp e1 e2 => mergeDistinctLists (getWeakExprFreeVars e1) (getWeakExprFreeVars e2)
- | WELam cv e => @removeFromDistinctList _ WeakExprVarEqDecidable cv (getWeakExprFreeVars e)
- | WETyLam cv e => getWeakExprFreeVars e
- | WECoLam cv e => getWeakExprFreeVars e
-
- (* the messy fixpoints below are required by Coq's termination conditions; trust me, I tried to get rid of them *)
- | WECase scrutinee tbranches tc type_params alts =>
- mergeDistinctLists (getWeakExprFreeVars scrutinee) (
- ((fix getWeakExprFreeVarsAlts (alts:Tree ??(AltCon*list WeakTypeVar*list WeakCoerVar*list WeakExprVar*WeakExpr))
- {struct alts} : list WeakExprVar :=
- match alts with
- | T_Leaf None => nil
- | T_Leaf (Some (DEFAULT,_,_,_,e)) => getWeakExprFreeVars e
- | T_Leaf (Some (LitAlt lit,_,_,_,e)) => getWeakExprFreeVars e
- | T_Leaf (Some ((DataAlt dc), tvars, cvars, evars,e)) => removeFromDistinctList' evars (getWeakExprFreeVars e)
- | T_Branch b1 b2 => mergeDistinctLists (getWeakExprFreeVarsAlts b1) (getWeakExprFreeVarsAlts b2)
- end) alts))
- | WELetRec mlr e => (fix removeVarsLetRec (mlr:Tree ??(WeakExprVar * WeakExpr))(cvl:list WeakExprVar) :=
- match mlr with
- | T_Leaf None => cvl
- | T_Leaf (Some (cv,e)) => removeFromDistinctList cv cvl
- | T_Branch b1 b2 => removeVarsLetRec b1 (removeVarsLetRec b2 cvl)
- end) mlr (mergeDistinctLists (getWeakExprFreeVars e)
- ((fix getWeakExprFreeVarsLetRec (mlr:Tree ??(WeakExprVar * WeakExpr)) :=
- match mlr with
- | T_Leaf None => nil
- | T_Leaf (Some (cv,e)) => getWeakExprFreeVars e
- | T_Branch b1 b2 => mergeDistinctLists (getWeakExprFreeVarsLetRec b1) (getWeakExprFreeVarsLetRec b2)
- end) mlr))
- end.
-
-(* wrap lambdas around an expression until it has no free expression variables *)
-Definition makeClosedExpression : WeakExpr -> WeakExpr :=
- fun me => (fix closeExpression (me:WeakExpr)(cvl:list WeakExprVar) :=
- match cvl with
- | nil => me
- | cv::cvl' => WELam cv (closeExpression me cvl')
- end) me (getWeakExprFreeVars me).
-