aboutsummaryrefslogtreecommitdiff
path: root/src/Haskell
diff options
context:
space:
mode:
authorTom Smeding <tom.smeding@gmail.com>2020-05-23 11:41:50 +0200
committerTom Smeding <tom.smeding@gmail.com>2020-05-23 11:50:45 +0200
commit18ea7b6804e09b1ae604b7fb9eadd542677f172d (patch)
treefba6e312c635ef0b14191011b65b56699e4532cf /src/Haskell
parent243f4f5b58014159be0c4dd7b0fc5c0a8021fd3c (diff)
Only rewrite _free_ variables in rewall
Diffstat (limited to 'src/Haskell')
-rw-r--r--src/Haskell/AST.hs19
1 files changed, 19 insertions, 0 deletions
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]