Support for list literals in Lambdas

src/Eval.hs

@@ -75,6 +75,9 @@ elimLambda = go
     go (SLambda [f] (SLambda [g] (SLambda [x] body)))
       | body == SApp (SVar f) (SApp (SVar g) (SVar x)) = _B
     -- General elimination
+    go (SLambda [v] (SList xs))
+      = elimLambda (SLambda [v] (foldr wrapTLeaf TLeaf xs))
+        where wrapTLeaf m r = SApp (SApp TLeaf m) r
     go (SLambda (v:vs) body)
       | null vs                    = toSKI v (elimLambda body)
       | otherwise                  = elimLambda (SLambda [v] (SLambda vs body))

test/Spec.hs

@@ -341,6 +341,10 @@ lambdas = testGroup "Lambda Evaluation Tests"
    , testCase "Lambda with a list literal" $ do
         let input = "f = (\\x : x)\nf [t (t t)]"
         runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
+
+  , testCase "Lambda with list literal" $ do
+      let input = "(\\a : [(a)]) 1"
+      runTricu input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
   ]
 
 providedLibraries :: TestTree

tricu.cabal

@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           tricu
-version:        0.15.0
+version:        0.16.0
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co