From 18ea7b6804e09b1ae604b7fb9eadd542677f172d Mon Sep 17 00:00:00 2001 From: Tom Smeding Date: Sat, 23 May 2020 11:41:50 +0200 Subject: Only rewrite _free_ variables in rewall --- src/Haskell/AST.hs | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'src/Haskell') diff --git a/src/Haskell/AST.hs b/src/Haskell/AST.hs index 072fd97..2238b6d 100644 --- a/src/Haskell/AST.hs +++ b/src/Haskell/AST.hs @@ -1,6 +1,7 @@ module Haskell.AST where import Data.List +import qualified Data.Set as Set import Pretty @@ -134,3 +135,21 @@ instance AllRefs Expr where instance AllRefs Inst where allRefs (Inst _ _ ds) = nub $ concatMap allRefs ds + + +boundVars :: Pat -> Set.Set Name +boundVars PatAny = mempty +boundVars (PatVar n) = Set.singleton n +boundVars (PatCon _ ps) = Set.unions (map boundVars ps) +boundVars (PatTup ps) = Set.unions (map boundVars ps) + +freeVariables :: Expr -> Set.Set Name +freeVariables (App e es) = freeVariables e <> Set.unions (map freeVariables es) +freeVariables (Ref n) = Set.singleton n +freeVariables (Con _) = mempty +freeVariables (Num _) = mempty +freeVariables (Tup es) = Set.unions (map freeVariables es) +freeVariables (Lam ns e) = freeVariables e Set.\\ Set.fromList ns +freeVariables (Case e pairs) = + freeVariables e <> Set.unions [freeVariables e' Set.\\ boundVars p + | (p, e') <- pairs] -- cgit v1.2.3-70-g09d2