Updates to demos

Also removes some broken list library functions

.gitignore

@@ -9,3 +9,4 @@
 WD
 bin/
 dist*
+.tricu_history

README.md

@@ -11,12 +11,11 @@ tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)
 ## Features
 
 - Tree Calculus operator: `t`
-- Assignments: `x = t t`
-- Immutable definitions
-- Lambda abstraction syntax: `id = (\a : a)`
+- Immutable definitions: `x = t t`
+- Lambda abstraction: `id = (a : a)`
 - List, Number, and String literals: `[(2) ("Hello")]` 
 - Function application: `not (not false)`
-- Higher order/first-class functions: `map (\a : append a "!") [("Hello")]`
+- Higher order/first-class functions: `map (a : append a "!") [("Hello")]`
 - Intensionality blurs the distinction between functions and data (see REPL examples)
 - Simple module system for code organization
 
@@ -24,15 +23,15 @@ tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)
 
 ```
 tricu < -- Anything after `--` on a single line is a comment
-tricu < id = (\a : a) -- Lambda abstraction is eliminated to tree calculus terms
-tricu < head (map (\i : append i " world!") [("Hello, ")])
+tricu < id = (a : a) -- Lambda abstraction is eliminated to tree calculus terms
+tricu < head (map (i : append i " world!") [("Hello, ")])
 tricu > "Hello,  world!"
-tricu < id (head (map (\i : append i " world!") [("Hello, ")]))
+tricu < id (head (map (i : append i " world!") [("Hello, ")]))
 tricu > "Hello,  world!"
 
 tricu < -- Intensionality! We can inspect the structure of a function or data.
-tricu < triage = (\a b c : t (t a b) c)
-tricu < test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
+tricu < triage = (a b c : t (t a b) c)
+tricu < test = triage "Leaf" (z : "Stem") (a b : "Fork")
 tricu < test (t t)
 tricu > "Stem"
 tricu < -- We can even convert a term back to source code (/demos/toSource.tri)
@@ -41,13 +40,21 @@ tricu > "(t (t (t t) (t t t)) (t t (t t t)))"
 tricu < -- or calculate its size (/demos/size.tri)
 tricu < size not?
 tricu > 12
+
+tricu < -- REPL Commands:
+tricu < !definitions  -- Lists all available definitions
+tricu < !output       -- Change output format (Tree, FSL, AST, etc.)
+tricu < !import       -- Import definitions from a file
+tricu < !exit         -- Exit the REPL
+tricu < !clear        -- ANSI screen clear
+tricu < !save         -- Save all REPL definitions to a file that you can !import
+tricu < !reset        -- Clear all REPL definitions
+tricu < !version      -- Print tricu version
 ```
 
 ## Installation and Use
 
-[Releases are available for Linux.](https://git.eversole.co/James/tricu/releases)
-
-Or you can easily build and run this project using [Nix](https://nixos.org/download/).
+You can easily build and run this project using [Nix](https://nixos.org/download/).
 
 - Quick Start (REPL): 
   - `nix run git+https://git.eversole.co/James/tricu`
@@ -84,6 +91,12 @@ tricu decode [OPTIONS]
                     Defaults to stdin.
 ```
 
+## Collaborating
+
+I am happy to accept issue reports, pull requests, or questions about tricu [via email](mailto:james@eversole.co).
+
+If you want to collaborate but don't want to email back-and-forth, please reach out via email once to let me know and I will provision a git.eversole.co account for you.
+
 ## Acknowledgements 
 
 Tree Calculus was discovered by [Barry Jay](https://github.com/barry-jay-personal/blog). 

demos/equality.tri

@@ -1,4 +1,5 @@
-!import "lib/base.tri" !Local
+!import "../lib/base.tri" !Local
+!import "../lib/list.tri" !Local
 
 main = lambdaEqualsTC
 
@@ -10,20 +11,17 @@ demo_true  = t t
 not_TC?     = t (t (t t) (t t t)) (t t (t t t))
 
 -- /demos/toSource.tri contains an explanation of `triage`
-demo_triage = \a b c : t (t a b) c
-demo_matchBool = (\ot of : demo_triage
-  of
-  (\_ : ot)
-  (\_ _ : ot)
-)
+demo_triage = a b c : t (t a b) c
+demo_matchBool = a b : demo_triage b (_ : a) (_ _ : a)
+
 -- Lambda representation of the Boolean `not` function
 not_Lambda? = demo_matchBool demo_false demo_true
 
--- Since tricu eliminates Lambda terms to SKI combinators, the tree form of many
+-- As tricu eliminates Lambda terms to SKI combinators, the tree form of many
 -- functions defined via Lambda terms are larger than the most efficient TC
--- representation. Between different languages that evaluate to tree calculus 
--- terms, the exact implementation of Lambda elimination may differ and lead 
--- to different tree representations even if they share extensional behavior.
+-- representation possible. Between different languages that evaluate to tree
+-- calculus terms, the exact implementation of Lambda elimination may differ
+-- and lead to different trees even if they share extensional behavior.
 
 -- Let's see if these are the same:
 lambdaEqualsTC = equal? not_TC? not_Lambda?

demos/levelOrderTraversal.tri

@@ -1,4 +1,5 @@
-!import "lib/base.tri" !Local
+!import "../lib/base.tri" Lib
+!import "../lib/list.tri" !Local
 
 main = exampleTwo
 -- Level Order Traversal of a labelled binary tree
@@ -17,15 +18,15 @@ main = exampleTwo
 --    /   /  \
 --   4   5    6
 
-label = \node : head node
+label = node : head node
 
-left = (\node : if (emptyList? node)
+left = node : (if (emptyList? node)
   []
   (if (emptyList? (tail node))
     []
     (head (tail node))))
 
-right = (\node : if (emptyList? node) 
+right = node : (if (emptyList? node)
   []
   (if (emptyList? (tail node))
     []
@@ -33,25 +34,25 @@ right = (\node : if (emptyList? node)
       []
       (head (tail (tail node))))))
 
-processLevel = y (\self queue : if (emptyList? queue) 
+processLevel = y (self queue : if (emptyList? queue)
   []
   (pair (map label queue) (self (filter
-    (\node : not? (emptyList? node)) 
+    (node : not? (emptyList? node))
       (append (map left queue) (map right queue))))))
 
-levelOrderTraversal_ = \a : processLevel (t a t)
+levelOrderTraversal_ = a : processLevel (t a t)
 
-toLineString = y (\self levels : if (emptyList? levels) 
+toLineString = y (self levels : if (emptyList? levels)
   ""
   (append
-    (append (map (\x : append x " ") (head levels)) "") 
+    (append (map (x : append x " ") (head levels)) "")
     (if (emptyList? (tail levels)) "" (append (t (t 10 t) t) (self (tail levels))))))
 
-levelOrderToString = \s : toLineString (levelOrderTraversal_ s)
+levelOrderToString = s : toLineString (levelOrderTraversal_ s)
 
-flatten = foldl (\acc x : append acc x) ""
+flatten = foldl (acc x : append acc x) ""
 
-levelOrderTraversal = \s : append (t 10 t) (flatten (levelOrderToString s))
+levelOrderTraversal = s : append (t 10 t) (flatten (levelOrderToString s))
 
 exampleOne = levelOrderTraversal [("1")
                                  [("2") [("4") t t] t]

demos/patternMatching.tri

@@ -0,0 +1,37 @@
+!import "../lib/patterns.tri" !Local
+
+-- We can do conditional pattern matching by providing a list of lists, where
+-- each sublist contains a boolean expression and a function to return if said
+-- boolean expression evaluates to true.
+
+value = 42
+main  = match value [[(equal? "Hello") (_ : ", world!")] [(equal? 42) (_ : "The answer.")]]
+
+-- < main
+-- > "The answer."
+
+matchExample = (x : match x
+  [[(equal? 1)  (_ : "one")]
+   [(equal? 2)  (_ : "two")]
+   [(equal? 3)  (_ : "three")]
+   [(equal? 4)  (_ : "four")]
+   [(equal? 5)  (_ : "five")]
+   [(equal? 6)  (_ : "six")]
+   [(equal? 7)  (_ : "seven")]
+   [(equal? 8)  (_ : "eight")]
+   [(equal? 9)  (_ : "nine")]
+   [(equal? 10) (_ : "ten")]
+   [ otherwise  (_ : "I ran out of fingers!")]])
+
+-- < matchExample 3
+-- > "three"
+-- < matchExample 5
+-- > "five"
+-- < matchExample 9
+-- > "nine"
+-- < matchExample 11
+-- > "I ran out of fingers!"
+-- < matchExample "three"
+-- > "I ran out of fingers!"
+-- < matchExample [("hello") ("world")]
+-- > "I ran out of fingers!"

demos/size.tri

@@ -1,12 +1,11 @@
-!import "lib/base.tri" !Local
+!import "../lib/base.tri" !Local
+!import "../lib/list.tri" !Local
 
 main = size size
 
-size = (\x :
-  (y (\self x :
-    compose succ
-      (triage
-        (\x : x)
+size = x : y (self x : compose succ (triage
+  id
   self
-        (\x y : compose (self x) (self y))
-        x)) x 0))
+  (x y : compose (self x) (self y))
+  x)
+) x 0

demos/toSource.tri

@@ -1,4 +1,5 @@
-!import "lib/base.tri" !Local
+!import "../lib/base.tri" !Local
+!import "../lib/list.tri" !Local
 
 main = toSource not?
 -- Thanks to intensionality, we can inspect the structure of a given value
@@ -17,25 +18,25 @@ main = toSource not?
 sourceLeaf = t (head "t")
 
 -- Stem case
-sourceStem = (\convert : (\a rest :
+sourceStem = convert : (a rest :
   t (head "(")                       -- Start with a left parenthesis "(".
     (t (head "t")                    -- Add a "t"
       (t (head " ")                  -- Add a space.
         (convert a                   -- Recursively convert the argument.
-          (t (head ")") rest))))))   -- Close with ")" and append the rest.
+          (t (head ")") rest)))))   -- Close with ")" and append the rest.
 
 -- Fork case
-sourceFork = (\convert : (\a b rest :
+sourceFork = convert : (a b rest :
   t (head "(")                           -- Start with a left parenthesis "(".
     (t (head "t")                        -- Add a "t"
       (t (head " ")                      -- Add a space.
         (convert a                       -- Recursively convert the first arg.
           (t (head " ")                  -- Add another space.
             (convert b                   -- Recursively convert the second arg.
-              (t (head ")") rest)))))))) -- Close with ")" and append the rest.
+              (t (head ")") rest))))))) -- Close with ")" and append the rest.
 
 -- Wrapper around triage 
-toSource_ = y (\self arg :
+toSource_ = y (self arg :
   triage
     sourceLeaf        -- `triage` "a" case, Leaf
     (sourceStem self) -- `triage` "b" case, Stem
@@ -43,7 +44,7 @@ toSource_ = y (\self arg :
     arg)              -- The term to be inspected
 
 -- toSource takes a single TC term and returns a String
-toSource = \v : toSource_ v ""
+toSource = v : toSource_ v ""
 
 exampleOne = toSource true -- OUT: "(t t)"
 exampleTwo = toSource not? -- OUT: "(t (t (t t) (t t t)) (t t (t t t)))"

flake.nix

@@ -34,6 +34,7 @@
         devShells.default = pkgs.mkShell {
           buildInputs = with pkgs; [
             haskellPackages.cabal-install
+            haskellPackages.ghc-events
             haskellPackages.ghcid
             customGHC
             upx

lib/base.tri

@@ -1,150 +1,74 @@
 false = t
 _     = t
 true  = t t
-k     = t t
-i     = t (t k) t
-s     = t (t (k t)) t
-m     = s i i
-b     = s (k s) k
-c     = s (s (k s) (s (k k) s)) (k k)
-id    = \a : a
+id    = a : a
+const = a b : a
 pair  = t
-if    = \cond then else : t (t else (t t then)) t cond
+if    = cond then else : t (t else (t t then)) t cond
 
-y = ((\mut wait fun : wait mut (\x : fun (wait mut x)))
-     (\x : x x)
-     (\a0 a1 a2 : t (t a0) (t t a2) a1))
+y = ((mut wait fun : wait mut (x : fun (wait mut x)))
+     (x : x x)
+     (a0 a1 a2 : t (t a0) (t t a2) a1))
 
-compose = \f g x : f (g x)
+compose = f g x : f (g x)
 
-triage = \leaf stem fork : t (t leaf stem) fork
-test   = triage "Leaf" (\_ : "Stem") (\_ _ : "Fork")
+triage = leaf stem fork : t (t leaf stem) fork
+test   = triage "Leaf" (_ : "Stem") (_ _ : "Fork")
 
-matchBool = (\ot of : triage
+matchBool = (ot of : triage
   of
-  (\_ : ot)
-  (\_ _ : ot)
+  (_ : ot)
+  (_ _ : ot)
 )
 
-matchList = \a b : triage a _ b
-
-matchPair = \a   : triage _ _ a
-
-not? = matchBool false true
-and? = matchBool id (\_ : false)
-emptyList? = matchList true (\_ _ : false)
-
-head = matchList t (\head _ : head)
-tail = matchList t (\_ tail : tail)
-
-or? = (\x y : 
-	matchBool 
-  	(matchBool (t t) (t t) y)
-  	(matchBool (t t) 0 y)
-  	x)
-xor? = matchBool id not?
-
-append = y (\self : matchList
-  (\k : k)
-  (\h r k : pair h (self r k)))
-
 lAnd = (triage
-  (\_     : false)
-  (\_ x   : x)
-  (\_ _ x : x))
+  (_     : false)
+  (_ x   : x)
+  (_ _ x : x))
 
 lOr = (triage
-  (\x     : x)
-  (\_ _   : true)
-  (\_ _ _ : true))
+  (x     : x)
+  (_ _   : true)
+  (_ _ _ : true))
 
-map_ = y (\self :
-  matchList
-    (\_ : t)
-    (\head tail f : pair (f head) (self tail f)))
-map = \f l : map_ l f
+matchPair = a : triage _ _ a
 
-equal? = y (\self : triage
+not? = matchBool false true
+and? = matchBool id (_ : false)
+
+or? = (x z : 
+  matchBool 
+    (matchBool true true z)
+    (matchBool true false z)
+    x)
+
+xor? = (x z : 
+  matchBool 
+    (matchBool false true z)
+    (matchBool true false z)
+    x)
+
+equal? = y (self : triage
   (triage
     true
-    (\_   : false)
-    (\_ _ : false))
-  (\ax :
+    (_   : false)
+    (_ _ : false))
+  (ax :
     triage
       false
       (self ax)
-      (\_ _ : false))
-  (\ax ay :
+      (_ _ : false))
+  (ax ay :
     triage
       false
-      (\_ : false)
-      (\bx by : lAnd (self ax bx) (self ay by))))
+      (_ : false)
+      (bx by : lAnd (self ax bx) (self ay by))))
 
-lExist? = y (\self x : matchList
-  false
-  (\h z : or? (equal? x h) (self x z)))
-
-filter_ = y (\self : matchList
-  (\_ : t)
-  (\head tail f : matchBool (t head) i (f head) (self tail f)))
-filter  = \f l : filter_ l f
-
-foldl_ = y (\self f l x : matchList (\acc : acc) (\head tail acc : self f tail (f acc head)) l x)
-foldl  = \f x l : foldl_ f l x
-
-foldr_ = y (\self x f l : matchList x (\head tail : f (self x f tail) head) l)
-foldr  = \f x l : foldr_ x f l
-
-succ = y (\self :
+succ = y (self :
   triage
     1
     t
     (triage
       (t (t t))
-      (\_ tail : t t (self tail))
+      (_ tail : t t (self tail))
       t))
-
-length = y (\self : matchList
-  0
-  (\_ tail : succ (self tail)))
-
-reverse = y (\self : matchList
-  t
-  (\head tail : append (self tail) (pair head t)))
-
-snoc = y (\self x : matchList
-  (pair x t)
-  (\h z : pair h (self x z)))
-
-count = y (\self x : matchList
-  0
-  (\h z : matchBool 
-    (succ (self x z))
-    (self x z)
-    (equal? x h)))
-
-last = y (\self : matchList
-  t
-  (\hd tl : matchBool
-    hd
-    (self tl)
-    (emptyList? tl)))
-
-all? = y (\self pred : matchList
-  true
-  (\h z : and? (pred h) (self pred z)))
-
-any? = y (\self pred : matchList
-  false
-  (\h z : or? (pred h) (self pred z)))
-
-unique_ = y (\self seen : matchList
-  t
-  (\head rest : matchBool
-    (self seen rest)
-    (pair head (self (pair head seen) rest))
-    (lExist? head seen)))
-unique = \xs : unique_ t xs
-
-intersect = \xs ys : filter (\x : lExist? x ys) xs
-union     = \xs ys : unique (append xs ys)

lib/list.tri

@@ -0,0 +1,70 @@
+!import "base.tri" !Local
+
+_ = t
+
+matchList = a b : triage a _ b
+
+emptyList? = matchList true (_ _ : false)
+head = matchList t (head _ : head)
+tail = matchList t (_ tail : tail)
+
+append = y (self : matchList
+  (k : k)
+  (h r k : pair h (self r k)))
+
+lExist? = y (self x : matchList
+  false
+  (h z : or? (equal? x h) (self x z)))
+
+map_ = y (self :
+  matchList
+    (_ : t)
+    (head tail f : pair (f head) (self tail f)))
+map = f l : map_ l f
+
+filter_ = y (self : matchList
+  (_ : t)
+  (head tail f : matchBool (t head) id (f head) (self tail f)))
+filter  = f l : filter_ l f
+
+foldl_ = y (self f l x : matchList (acc : acc) (head tail acc : self f tail (f acc head)) l x)
+foldl  = f x l : foldl_ f l x
+
+foldr_ = y (self x f l : matchList x (head tail : f (self x f tail) head) l)
+foldr  = f x l : foldr_ x f l
+
+length = y (self : matchList
+  0
+  (_ tail : succ (self tail)))
+
+reverse = y (self : matchList
+  t
+  (head tail : append (self tail) (pair head t)))
+
+snoc = y (self x : matchList
+  (pair x t)
+  (h z : pair h (self x z)))
+
+count = y (self x : matchList
+  0
+  (h z : matchBool
+    (succ (self x z))
+    (self x z)
+    (equal? x h)))
+
+last = y (self : matchList
+  t
+  (hd tl : matchBool
+    hd
+    (self tl)
+    (emptyList? tl)))
+
+all? = y (self pred : matchList
+  true
+  (h z : and? (pred h) (self pred z)))
+
+any? = y (self pred : matchList
+  false
+  (h z : or? (pred h) (self pred z)))
+
+intersect = xs ys : filter (x : lExist? x ys) xs

lib/patterns.tri

@@ -0,0 +1,24 @@
+!import "base.tri" !Local
+!import "list.tri" List
+
+match_ = y (self value patterns :
+  triage
+    t
+    (_ : t)
+    (pattern rest :
+      triage
+        t
+        (_ : t)
+        (test result :
+          if (test value)
+             (result value)
+             (self value rest))
+        pattern)
+    patterns)
+
+match = (value patterns :
+  match_ value (List.map (sublist :
+    pair (List.head sublist) (List.head (List.tail sublist)))
+    patterns))
+
+otherwise = const (t t)

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))
@@ -141,18 +144,23 @@ reorderDefs env defs
 
 buildDepGraph :: [TricuAST] -> Map.Map String (Set.Set String)
 buildDepGraph topDefs
-  | not (null duplicateNames) =
+  | not (null conflictingDefs) =
       errorWithoutStackTrace $
-        "Duplicate definitions detected: " ++ show duplicateNames
+        "Conflicting definitions detected: " ++ show conflictingDefs
   | otherwise =
       Map.fromList
         [ (name, depends topDefs (SDef name [] body))
         | SDef name _ body <- topDefs]
   where
-    names = [name | SDef name _ _ <- topDefs]
-    duplicateNames =
-      [ name | (name, count) <- Map.toList (countOccurrences names) , count > 1]
-    countOccurrences = foldr (\x -> Map.insertWith (+) x 1) Map.empty
+    defsMap = Map.fromListWith (++)
+      [(name, [(name, body)]) | SDef name _ body <- topDefs]
+
+    conflictingDefs =
+      [ name
+      | (name, defs) <- Map.toList defsMap
+      , let bodies = map snd defs
+      , not $ all (== head bodies) (tail bodies)
+      ]
 
 sortDeps :: Map.Map String (Set.Set String) -> [String]
 sortDeps graph = go [] Set.empty (Map.keys graph)

src/FileEval.hs

@@ -6,12 +6,34 @@ import Parser
 import Research
 
 import Data.List       (partition)
+import Data.Maybe      (mapMaybe)
 import Control.Monad   (foldM)
 import System.IO
+import System.FilePath (takeDirectory, normalise, (</>))
 
 import qualified Data.Map as Map
 import qualified Data.Set as Set
 
+extractMain :: Env -> Either String T
+extractMain env =
+  case Map.lookup "main" env of
+    Just result -> Right result
+    Nothing -> Left "No `main` function detected"
+
+processImports :: Set.Set FilePath -> FilePath -> FilePath -> [TricuAST]
+                 -> Either String ([TricuAST], [(FilePath, String, FilePath)])
+processImports seen base currentPath asts =
+  let (imports, nonImports) = partition isImp asts
+      importPaths = mapMaybe getImportInfo imports
+  in if currentPath `Set.member` seen
+     then Left $ "Encountered cyclic import: " ++ currentPath
+     else Right (nonImports, importPaths)
+  where
+    isImp (SImport _ _) = True
+    isImp _ = False
+    getImportInfo (SImport p n) = Just (p, n, makeRelativeTo currentPath p)
+    getImportInfo _ = Nothing
+
 evaluateFileResult :: FilePath -> IO T
 evaluateFileResult filePath = do
   contents <- readFile filePath
@@ -19,11 +41,11 @@ evaluateFileResult filePath = do
   case parseProgram tokens of
     Left err -> errorWithoutStackTrace (handleParseError err)
     Right ast -> do
-      ast <- preprocessFile filePath
-      let finalEnv = evalTricu Map.empty ast
-      case Map.lookup "main" finalEnv of
-        Just finalResult -> return finalResult
-        Nothing -> errorWithoutStackTrace "No `main` function detected"
+      processedAst <- preprocessFile filePath
+      let finalEnv = evalTricu Map.empty processedAst
+      case extractMain finalEnv of
+        Right result -> return result
+        Left err -> errorWithoutStackTrace err
 
 evaluateFile :: FilePath -> IO Env
 evaluateFile filePath = do
@@ -46,38 +68,33 @@ evaluateFileWithContext env filePath = do
       pure $ evalTricu env ast
 
 preprocessFile :: FilePath -> IO [TricuAST]
-preprocessFile = preprocessFile' Set.empty
+preprocessFile p = preprocessFile' Set.empty p p
 
-preprocessFile' :: Set.Set FilePath -> FilePath -> IO [TricuAST]
-preprocessFile' inProgress filePath
-  | filePath `Set.member` inProgress = 
-      errorWithoutStackTrace $ "Encountered cyclic import: " ++ filePath
-  | otherwise = do
-      contents <- readFile filePath
+preprocessFile' :: Set.Set FilePath -> FilePath -> FilePath -> IO [TricuAST]
+preprocessFile' seen base currentPath = do
+  contents <- readFile currentPath
   let tokens = lexTricu contents
   case parseProgram tokens of
     Left err -> errorWithoutStackTrace (handleParseError err)
-        Right asts -> do
-          let (imports, nonImports) = partition isImport asts
-          let newInProgress = Set.insert filePath inProgress
-          importedASTs <- concat <$> 
-            mapM (processImport newInProgress "") imports
-          pure $ importedASTs ++ nonImports
+    Right ast ->
+      case processImports seen base currentPath ast of
+        Left err -> errorWithoutStackTrace err
+        Right (nonImports, importPaths) -> do
+          let seen' = Set.insert currentPath seen
+          imported <- concat <$> mapM (processImportPath seen' base) importPaths
+          pure $ imported ++ nonImports
   where
-    isImport :: TricuAST -> Bool
-    isImport (SImport _ _) = True
-    isImport _             = False
+    processImportPath seen base (path, name, importPath) = do
+      ast <- preprocessFile' seen base importPath
+      pure $ map (nsDefinition (if name == "!Local" then "" else name))
+           $ filter (not . isImp) ast
+    isImp (SImport _ _) = True
+    isImp _ = False
 
-    processImport :: Set.Set FilePath -> String -> TricuAST -> IO [TricuAST]
-    processImport prog currentModule (SImport path "!Local") = do
-      ast <- preprocessFile' prog path
-      let defs = filter (not . isImport) ast
-      pure $ map (nsDefinition currentModule) defs
-    processImport prog _ (SImport path name) = do
-      ast <- preprocessFile' prog path
-      let defs = filter (not . isImport) ast
-      pure $ map (nsDefinition name) defs
-    processImport _ _ _ = error "Unexpected non-import in processImport"
+makeRelativeTo :: FilePath -> FilePath -> FilePath
+makeRelativeTo f i =
+    let d = takeDirectory f
+    in normalise $ d </> i
 
 nsDefinitions :: String -> [TricuAST] -> [TricuAST]
 nsDefinitions moduleName = map (nsDefinition moduleName)

src/Lexer.hs

@@ -3,6 +3,7 @@ module Lexer where
 import Research
 
 import Control.Monad               (void)
+import Data.Functor                (($>))
 import Data.Void
 import Text.Megaparsec
 import Text.Megaparsec.Char hiding (space)
@@ -40,7 +41,6 @@ tricuLexer = do
       , try stringLiteral
       , assign
       , colon
-      , backslash
       , openParen
       , closeParen
       , openBracket
@@ -54,7 +54,7 @@ lexTricu input = case runParser tricuLexer "" input of
 
 
 keywordT :: Lexer LToken
-keywordT = string "t" *> notFollowedBy alphaNumChar *> pure LKeywordT
+keywordT = string "t" *> notFollowedBy alphaNumChar $> LKeywordT
 
 identifier :: Lexer LToken
 identifier = do
@@ -63,7 +63,7 @@ identifier = do
               <|> digitChar <|> char '_' <|> char '-' <|> char '?'
               <|> char '$'  <|> char '#' <|> char '@' <|> char '%'
   let name = first : rest
-  if (name == "t" || name == "!result")
+  if name == "t" || name == "!result"
     then fail "Keywords (`t`, `!result`) cannot be used as an identifier"
     else return (LIdentifier name)
 
@@ -76,7 +76,7 @@ namespace = do
   return (LNamespace name)
 
 dot :: Lexer LToken
-dot = char '.' *> pure LDot
+dot = char '.' $> LDot
 
 lImport :: Lexer LToken
 lImport = do
@@ -88,28 +88,25 @@ lImport = do
   return (LImport path name)
 
 assign :: Lexer LToken
-assign = char '=' *> pure LAssign
+assign = char '=' $> LAssign
 
 colon :: Lexer LToken
-colon = char ':' *> pure LColon
-
-backslash :: Lexer LToken
-backslash = char '\\' *> pure LBackslash
+colon = char ':' $> LColon
 
 openParen :: Lexer LToken
-openParen = char '(' *> pure LOpenParen
+openParen = char '(' $> LOpenParen
 
 closeParen :: Lexer LToken
-closeParen = char ')' *> pure LCloseParen
+closeParen = char ')' $> LCloseParen
 
 openBracket :: Lexer LToken
-openBracket = char '[' *> pure LOpenBracket
+openBracket = char '[' $> LOpenBracket
 
 closeBracket :: Lexer LToken
-closeBracket = char ']' *> pure LCloseBracket
+closeBracket = char ']' $> LCloseBracket
 
 lnewline :: Lexer LToken
-lnewline = char '\n' *> pure LNewline
+lnewline = char '\n' $> LNewline
 
 sc :: Lexer ()
 sc = space
@@ -125,7 +122,22 @@ integerLiteral = do
 stringLiteral :: Lexer LToken
 stringLiteral = do
   char '"'
-  content <- many (noneOf ['"'])
-  char '"' --"
+  content <- manyTill Lexer.charLiteral (char '"')
   return (LStringLiteral content)
 
+charLiteral :: Lexer Char
+charLiteral = escapedChar <|> normalChar
+  where
+    normalChar = noneOf ['"', '\\']
+    escapedChar = do
+      void $ char '\\'
+      c <- oneOf ['n', 't', 'r', 'f', 'b', '\\', '"', '\'']
+      return $ case c of
+        'n'  -> '\n'
+        't'  -> '\t'
+        'r'  -> '\r'
+        'f'  -> '\f'
+        'b'  -> '\b'
+        '\\' -> '\\'
+        '"'  -> '"'
+        '\'' -> '\''

src/Parser.hs

@@ -130,7 +130,6 @@ parseFunctionM = do
 parseLambdaM :: ParserM TricuAST
 parseLambdaM = do
   let ident = (\case LIdentifier _ -> True; _ -> False)
-  _      <- satisfyM (== LBackslash)
   params <- some (satisfyM ident)
   _      <- satisfyM (== LColon)
   scnParserM
@@ -145,11 +144,11 @@ parseLambdaExpressionM = choice
 
 parseAtomicLambdaM :: ParserM TricuAST
 parseAtomicLambdaM = choice
-  [ parseVarM
+  [ try parseLambdaM
+  , parseVarM
   , parseTreeLeafM
   , parseLiteralM
   , parseListLiteralM
-  , try parseLambdaM
   , between (satisfyM (== LOpenParen)) (satisfyM (== LCloseParen)) parseLambdaExpressionM
   ]
 
@@ -205,7 +204,8 @@ parseTreeLeafOrParenthesizedM = choice
 
 parseAtomicM :: ParserM TricuAST
 parseAtomicM = choice
-  [ parseVarM
+  [ try parseLambdaM
+  , parseVarM
   , parseTreeLeafM
   , parseListLiteralM
   , parseGroupedM

src/REPL.hs

@@ -6,68 +6,153 @@ import Lexer
 import Parser
 import Research
 
-import Control.Exception      (SomeException, catch)
-import Control.Monad.IO.Class (liftIO)
+import Control.Exception         (IOException, SomeException, catch
+                                 , displayException)
+import Control.Monad             (forM_)
 import Control.Monad.Catch       (handle, MonadCatch)
-import Data.Char              (isSpace)
-import Data.List              ( dropWhile
-                              , dropWhileEnd
-                              , intercalate
-                              , isPrefixOf)
+import Control.Monad.IO.Class    (liftIO)
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Maybe (MaybeT(..), runMaybeT)
+import Data.Char                 (isSpace, isUpper)
+import Data.List                 (dropWhile, dropWhileEnd, isPrefixOf)
+import Data.Version (showVersion)
+import Paths_tricu (version)
 import System.Console.Haskeline
 
 import qualified Data.Map as Map
+import qualified Data.Text as T
+import qualified Data.Text.IO as T
 
 repl :: Env -> IO ()
-repl env = runInputT defaultSettings (withInterrupt (loop env True))
+repl env = runInputT settings (withInterrupt (loop env Decode))
   where
-    loop :: Env -> Bool -> InputT IO ()
-    loop env decode = handle (interruptHandler env decode) $ do
+    settings :: Settings IO
+    settings = Settings
+      { complete = completeWord Nothing " \t" completeCommands
+      , historyFile = Just "~/.local/state/tricu/history"
+      , autoAddHistory = True
+      }
+
+    completeCommands :: String -> IO [Completion]
+    completeCommands str = return $ map simpleCompletion $
+      filter (str `isPrefixOf`) commands
+      where
+        commands = [ "!exit"
+                   , "!output"
+                   , "!definitions"
+                   , "!import"
+                   , "!clear"
+                   , "!save"
+                   , "!reset"
+                   , "!version"
+                   ]
+
+    loop :: Env -> EvaluatedForm -> InputT IO ()
+    loop env form = handle (interruptHandler env form) $ do
       minput <- getInputLine "tricu < "
       case minput of
         Nothing -> outputStrLn "Exiting tricu"
         Just s
-          | strip s == "" -> loop env decode
+          | strip s == "" -> loop env form
           | strip s == "!exit" -> outputStrLn "Exiting tricu"
-          | strip s == "!decode" -> do
-              outputStrLn $ "Decoding " ++ (if decode then "disabled" else "enabled")
-              loop env (not decode)
-          | "!import" `isPrefixOf` strip s -> do
-              let afterImport = dropWhile (== ' ') $ drop (length ("!import" :: String)) (strip s)
-              if not (null afterImport)
-                then outputStrLn "Warning: REPL imports are interactive; \
-                                  \additional arguments are ignored."
-                else pure ()
-              path <- getInputLine "File path to load < "
-              case path of
-                Nothing -> do
-                  outputStrLn "No input received; stopping import."
-                  loop env decode
-                Just p -> do
-                  loadedEnv <- liftIO $ evaluateFileWithContext env
-                    (strip p) `catch` \e -> errorHandler env e
-                  loop (Map.delete "!result" (Map.union loadedEnv env)) decode
-          | take 2 s == "--" -> loop env decode
+          | strip s == "!clear" -> do
+              liftIO $ putStr "\ESC[2J\ESC[H"
+              loop env form
+          | strip s == "!reset" -> do
+              outputStrLn "Environment reset to initial state"
+              loop Map.empty form
+          | strip s == "!version" -> do
+              outputStrLn $ "tricu version " ++ showVersion version
+              loop env form
+          | "!save" `isPrefixOf` strip s -> handleSave env form
+          | strip s == "!output" -> handleOutput env form
+          | strip s == "!definitions" -> do
+              let defs = Map.keys $ Map.delete "!result" env
+              if null defs
+                then outputStrLn "No definitions discovered."
+                else do
+                  outputStrLn "Available definitions:"
+                  mapM_ outputStrLn defs
+              loop env form
+          | "!import" `isPrefixOf` strip s -> handleImport env form
+          | take 2 s == "--" -> loop env form
           | otherwise -> do
-              newEnv <- liftIO $ processInput env s decode `catch` errorHandler env
-              loop newEnv decode
+              newEnv <- liftIO $ processInput env s form `catch` errorHandler env
+              loop newEnv form
 
-    interruptHandler :: Env -> Bool -> Interrupt -> InputT IO ()
-    interruptHandler env decode _ = do
+    handleOutput :: Env -> EvaluatedForm -> InputT IO ()
+    handleOutput env currentForm = do
+      let formats = [Decode, TreeCalculus, FSL, AST, Ternary, Ascii]
+      outputStrLn "Available output formats:"
+      mapM_ (\(i, f) -> outputStrLn $ show i ++ ". " ++ show f)
+        (zip [1..] formats)
+
+      result <- runMaybeT $ do
+        input <- MaybeT $ getInputLine "Select output format (1-6) < "
+        case reads input of
+          [(n, "")] | n >= 1 && n <= 6 ->
+            return $ formats !! (n-1)
+          _ -> MaybeT $ return Nothing
+
+      case result of
+        Nothing -> do
+          outputStrLn "Invalid selection. Keeping current output format."
+          loop env currentForm
+        Just newForm -> do
+          outputStrLn $ "Output format changed to: " ++ show newForm
+          loop env newForm
+
+    handleImport :: Env -> EvaluatedForm -> InputT IO ()
+    handleImport env form = do
+      res <- runMaybeT $ do
+        let fset = setComplete completeFilename defaultSettings
+        path <- MaybeT $ runInputT fset $
+          getInputLineWithInitial "File path to load < " ("", "")
+
+        text <- MaybeT $ liftIO $ handle (\e -> do
+            putStrLn $ "Error reading file: " ++ displayException (e :: IOException)
+            return Nothing
+          ) $ Just <$> readFile (strip path)
+
+        case parseProgram (lexTricu text) of
+          Left err -> do
+            lift $ outputStrLn $ "Parse error: " ++ handleParseError err
+            MaybeT $ return Nothing
+          Right ast -> do
+            ns <- MaybeT $ runInputT defaultSettings $
+              getInputLineWithInitial "Namespace (or !Local for no namespace) < " ("", "")
+
+            let name = strip ns
+            if (name /= "!Local" && (null name || not (isUpper (head name)))) then do
+                lift $ outputStrLn "Namespace must start with an uppercase letter"
+                MaybeT $ return Nothing
+            else do
+                prog <- liftIO $ preprocessFile (strip path)
+                let code = case name of
+                      "!Local" -> prog
+                      _ -> nsDefinitions name prog
+                    env' = evalTricu env code
+                return env'
+      case res of
+        Nothing -> do
+          outputStrLn "Import cancelled"
+          loop env form
+        Just env' ->
+          loop (Map.delete "!result" env') form
+
+    interruptHandler :: Env -> EvaluatedForm -> Interrupt -> InputT IO ()
+    interruptHandler env form _ = do
       outputStrLn "Interrupted with CTRL+C\n\
                   \You can use the !exit command or CTRL+D to exit"
-      loop env decode
+      loop env form
 
-    processInput :: Env -> String -> Bool -> IO Env
-    processInput env input decode = do
+    processInput :: Env -> String -> EvaluatedForm -> IO Env
+    processInput env input form = do
       let asts   = parseTricu input
           newEnv = evalTricu env asts
       case Map.lookup "!result" newEnv of
         Just r -> do
-          putStrLn $ "tricu > " ++ 
-            if decode 
-              then decodeResult r
-              else show r
+          putStrLn $ "tricu > " ++ formatResult form r
         Nothing -> pure ()
       return newEnv
 
@@ -78,3 +163,28 @@ repl env = runInputT defaultSettings (withInterrupt (loop env True))
 
     strip :: String -> String
     strip = dropWhileEnd isSpace . dropWhile isSpace
+
+    handleSave :: Env -> EvaluatedForm -> InputT IO ()
+    handleSave env form = do
+      let fset = setComplete completeFilename defaultSettings
+      path <- runInputT fset $
+        getInputLineWithInitial "File to save < " ("", "")
+
+      case path of
+        Nothing -> do
+          outputStrLn "Save cancelled"
+          loop env form
+        Just p -> do
+          let definitions = Map.toList $ Map.delete "!result" env
+              filepath = strip p
+
+          outputStrLn "Starting save..."
+          liftIO $ writeFile filepath ""
+          outputStrLn "File created..."
+          forM_ definitions $ \(name, value) -> do
+            let content = name ++ " = " ++ formatResult TreeCalculus value ++ "\n"
+            outputStrLn $ "Writing definition: " ++ name ++ " with length " ++ show (length content)
+            liftIO $ appendFile filepath content
+          outputStrLn $ "Saved " ++ show (length definitions) ++ " definitions to " ++ p
+
+          loop env form

src/Research.hs

@@ -1,6 +1,5 @@
 module Research where
 
-import Control.Monad.State
 import Data.List                 (intercalate)
 import Data.Map                  (Map)
 import Data.Text                 (Text, replace)
@@ -39,7 +38,6 @@ data LToken
   | LAssign
   | LColon
   | LDot
-  | LBackslash
   | LOpenParen
   | LCloseParen
   | LOpenBracket
@@ -55,15 +53,24 @@ data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii | Decode
 -- Environment containing previously evaluated TC terms
 type Env = Map.Map String T
 
--- Tree Calculus Reduction
+-- Tree Calculus Reduction Rules
+{- 
+  The t operator is left associative.
+  1.  t  t      a b       -> a
+  2.  t (t a)   b c       -> a c (b c)
+  3a. t (t a b) c t       -> a
+  3b. t (t a b) c (t u)   -> b u
+  3c. t (t a b) c (t u v) -> c u v
+-}
 apply :: T -> T -> T
+apply (Fork Leaf a)         _         = a
+apply (Fork (Stem a) b) c             = apply (apply a c) (apply b c)
+apply (Fork (Fork a  b) c)  Leaf      = a
+apply (Fork (Fork a  b) c) (Stem u)   = apply b u
+apply (Fork (Fork a  b) c) (Fork u v) = apply (apply c u) v
+-- Left associative `t`
 apply  Leaf b                         = Stem b
 apply (Stem a) b                      = Fork a b
-apply (Fork Leaf a) _                   = a
-apply (Fork (Stem a1) a2) b             = apply (apply a1 b) (apply a2 b)
-apply (Fork (Fork a1 a2) a3) Leaf       = a1
-apply (Fork (Fork a1 a2) a3) (Stem u)   = apply a2 u
-apply (Fork (Fork a1 a2) a3) (Fork u v) = apply (apply a3 u) v
 
 -- Booleans
 _false :: T
@@ -77,7 +84,7 @@ _not = Fork (Fork _true (Fork Leaf _false)) Leaf
 
 -- Marshalling
 ofString :: String -> T
-ofString str = ofList (map ofNumber (map fromEnum str))
+ofString str = ofList $ map (ofNumber . fromEnum) str
 
 ofNumber :: Int -> T
 ofNumber 0 = Leaf
@@ -87,8 +94,7 @@ ofNumber n =
     (ofNumber (n `div` 2))
 
 ofList :: [T] -> T
-ofList [] = Leaf
-ofList (x:xs) = Fork x (ofList xs)
+ofList = foldr Fork Leaf
 
 toNumber :: T -> Either String Int
 toNumber Leaf = Right 0
@@ -126,7 +132,7 @@ toSimpleT s = T.unpack
   $ replace "Fork" "t"
   $ replace "Stem" "t"
   $ replace "Leaf" "t"
-  $ (T.pack s)
+  $ T.pack s
 
 toTernaryString :: T -> String
 toTernaryString Leaf = "0"
@@ -153,8 +159,18 @@ toAscii tree = go tree "" True
         ++ go right (prefix ++ (if isLast then "    " else "|   ")) True
 
 decodeResult :: T -> String
-decodeResult tc
-  | Right num  <- toNumber tc = show num
-  | Right str  <- toString tc = "\"" ++ str ++ "\""
-  | Right list <- toList tc   = "[" ++ intercalate ", " (map decodeResult list) ++ "]"
-  | otherwise                 = formatResult TreeCalculus tc
+decodeResult Leaf = "t"
+decodeResult tc =
+  case (toString tc, toList tc, toNumber tc) of
+    (Right s, _, _) | all isCommonChar s -> "\"" ++ s ++ "\""
+    (_, _, Right n) -> show n
+    (_, Right xs@(_:_), _) -> "[" ++ intercalate ", " (map decodeResult xs) ++ "]"
+    (_, Right [], _) -> "[]"
+    _ -> formatResult TreeCalculus tc
+  where
+    isCommonChar c =
+      let n = fromEnum c
+      in (n >= 32 && n <= 126)
+         || n == 9
+         || n == 10
+         || n == 13

test/Spec.hs

@@ -30,10 +30,11 @@ tests = testGroup "Tricu Tests"
   , parser
   , simpleEvaluation
   , lambdas
-  , baseLibrary
+  , providedLibraries
   , fileEval
   , modules
   , demos
+  , decoding
   ]
 
 lexer :: TestTree
@@ -50,7 +51,22 @@ lexer = testGroup "Lexer Tests"
 
   , testCase "Lex escaped characters in strings" $ do
       let input = "\"hello\\nworld\""
-          expect = Right [LStringLiteral "hello\\nworld"]
+          expect = Right [LStringLiteral "hello\nworld"]
+      runParser tricuLexer "" input @?= expect
+
+  , testCase "Lex multiple escaped characters in strings" $ do
+      let input = "\"tab:\\t newline:\\n quote:\\\" backslash:\\\\\""
+          expect = Right [LStringLiteral "tab:\t newline:\n quote:\" backslash:\\"]
+      runParser tricuLexer "" input @?= expect
+
+  , testCase "Lex escaped characters in string literals" $ do
+      let input = "x = \"line1\\nline2\\tindented\""
+          expect = Right [LIdentifier "x", LAssign, LStringLiteral "line1\nline2\tindented"]
+      runParser tricuLexer "" input @?= expect
+
+  , testCase "Lex empty string with escape sequence" $ do
+      let input = "\"\\\"\""
+          expect = Right [LStringLiteral "\""]
       runParser tricuLexer "" input @?= expect
 
   , testCase "Lex mixed literals" $ do
@@ -86,7 +102,7 @@ parser = testGroup "Parser Tests"
         Right _ -> assertFailure "Expected failure when trying to assign the value of T"
 
   , testCase "Parse function definitions" $ do
-      let input = "x = (\\a b c : a)"
+      let input = "x = (a b c : a)"
           expect = SDef "x" [] (SLambda ["a"] (SLambda ["b"] (SLambda ["c"] (SVar "a"))))
       parseSingle input @?= expect
 
@@ -106,7 +122,7 @@ parser = testGroup "Parser Tests"
       parseSingle input @?= expect
 
   , testCase "Parse function with applications" $ do
-      let input  = "f = (\\x : t x)"
+      let input  = "f = (x : t x)"
           expect = SDef "f" [] (SLambda ["x"] (SApp TLeaf (SVar "x")))
       parseSingle input @?= expect
 
@@ -148,22 +164,22 @@ parser = testGroup "Parser Tests"
       parseSingle input @?= expect
 
   , testCase "Parse nested parentheses in function body" $ do
-      let input  = "f = (\\x : t (t (t t)))"
+      let input  = "f = (x : t (t (t t)))"
           expect = SDef "f" [] (SLambda ["x"] (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf))))
       parseSingle input @?= expect
 
   , testCase "Parse lambda abstractions" $ do
-      let input  = "(\\a : a)"
+      let input  = "(a : a)"
           expect = (SLambda ["a"] (SVar "a"))
       parseSingle input @?= expect
 
   , testCase "Parse multiple arguments to lambda abstractions" $ do
-      let input  = "x = (\\a b : a)"
+      let input  = "x = (a b : a)"
           expect = SDef "x" [] (SLambda ["a"] (SLambda ["b"] (SVar "a")))
       parseSingle input @?= expect
 
   , testCase "Grouping T terms with parentheses in function application" $ do
-      let input  = "x = (\\a : a)\nx (t)"
+      let input  = "x = (a : a)\nx (t)"
           expect = [SDef "x" [] (SLambda ["a"] (SVar "a")),SApp (SVar "x") TLeaf]
       parseTricu input @?= expect
 
@@ -258,7 +274,7 @@ simpleEvaluation = testGroup "Evaluation Tests"
 
   , testCase "Apply identity to Boolean Not" $ do
       let not = "(t (t (t t) (t t t)) t)"
-      let input = "x = (\\a : a)\nx " ++ not
+      let input = "x = (a : a)\nx " ++ not
           env = evalTricu Map.empty (parseTricu input)
       result env @?= Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
   ]
@@ -266,214 +282,182 @@ simpleEvaluation = testGroup "Evaluation Tests"
 lambdas :: TestTree
 lambdas = testGroup "Lambda Evaluation Tests"
   [ testCase "Lambda Identity Function" $ do
-      let input = "id = (\\x : x)\nid t"
+      let input = "id = (x : x)\nid t"
       runTricu input @?= "Leaf"
 
   , testCase "Lambda Constant Function (K combinator)" $ do
-      let input = "k = (\\x y : x)\nk t (t t)"
+      let input = "k = (x y : x)\nk t (t t)"
       runTricu input @?= "Leaf"
 
   , testCase "Lambda Application with Variable" $ do
-      let input = "id = (\\x : x)\nval = t t\nid val"
+      let input = "id = (x : x)\nval = t t\nid val"
       runTricu input @?= "Stem Leaf"
 
   , testCase "Lambda Application with Multiple Arguments" $ do
-      let input = "apply = (\\f x y : f x y)\nk = (\\a b : a)\napply k t (t t)"
+      let input = "apply = (f x y : f x y)\nk = (a b : a)\napply k t (t t)"
       runTricu input @?= "Leaf"
 
    , testCase "Nested Lambda Application" $ do
-      let input = "apply = (\\f x y : f x y)\nid = (\\x : x)\napply (\\f x : f x) id t"
+      let input = "apply = (f x y : f x y)\nid = (x : x)\napply (f x : f x) id t"
       runTricu input @?= "Leaf"
 
   , testCase "Lambda with a complex body" $ do
-      let input = "f = (\\x : t (t x))\nf t"
+      let input = "f = (x : t (t x))\nf t"
       runTricu input @?= "Stem (Stem Leaf)"
 
   , testCase "Lambda returning a function" $ do
-      let input = "f = (\\x : (\\y : x))\ng = f t\ng (t t)"
+      let input = "f = (x : (y : x))\ng = f t\ng (t t)"
       runTricu input @?= "Leaf"
 
   , testCase "Lambda with Shadowing" $ do
-      let input = "f = (\\x : (\\x : x))\nf t (t t)"
+      let input = "f = (x : (x : x))\nf t (t t)"
       runTricu input @?= "Stem Leaf"
 
    , testCase "Lambda returning another lambda" $ do
-      let input = "k = (\\x : (\\y : x))\nk_app = k t\nk_app (t t)"
+      let input = "k = (x : (y : x))\nk_app = k t\nk_app (t t)"
       runTricu input @?= "Leaf"
 
    , testCase "Lambda with free variables" $ do
-      let input = "y = t t\nf = (\\x : y)\nf t"
+      let input = "y = t t\nf = (x : y)\nf t"
       runTricu input @?= "Stem Leaf"
 
    , testCase "SKI Composition" $ do
-      let input = "s = (\\x y z : x z (y z))\nk = (\\x y : x)\ni = (\\x : x)\ncomp = s k i\ncomp t (t t)"
+      let input = "s = (x y z : x z (y z))\nk = (x y : x)\ni = (x : x)\ncomp = s k i\ncomp t (t t)"
       runTricu input @?= "Stem (Stem Leaf)"
 
    , testCase "Lambda with multiple parameters and application" $ do
-      let input = "f = (\\a b c : t a b c)\nf t (t t) (t t t)"
+      let input = "f = (a b c : t a b c)\nf t (t t) (t t t)"
       runTricu input @?= "Stem Leaf"
 
    , testCase "Lambda with nested application in the body" $ do
-      let input = "f = (\\x : t (t (t x)))\nf t"
+      let input = "f = (x : t (t (t x)))\nf t"
       runTricu input @?= "Stem (Stem (Stem Leaf))"
 
     , testCase "Lambda returning a function and applying it" $ do
-        let input = "f = (\\x : (\\y : t x y))\ng = f t\ng (t t)"
+        let input = "f = (x : (y : t x y))\ng = f t\ng (t t)"
         runTricu input @?= "Fork Leaf (Stem Leaf)"
 
     , testCase "Lambda applying a variable" $ do
-        let input = "id = (\\x : x)\na = t t\nid a"
+        let input = "id = (x : x)\na = t t\nid a"
         runTricu input @?= "Stem Leaf"
 
     , testCase "Nested lambda abstractions in the same expression" $ do
-        let input = "f = (\\x : (\\y : x y))\ng = (\\z : z)\nf g t"
+        let input = "f = (x : (y : x y))\ng = (z : z)\nf g t"
         runTricu input @?= "Leaf"
 
-  , testCase "Lambda with a string literal" $ do
-        let input = "f = (\\x : x)\nf \"hello\""
+  , testCase "Lambda applied to string literal" $ do
+        let input = "f = (x : x)\nf \"hello\""
         runTricu input @?= "Fork (Fork Leaf (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) Leaf))))"
 
 
-   , testCase "Lambda with an integer literal" $ do
-        let input = "f = (\\x : x)\nf 42"
+   , testCase "Lambda applied to integer literal" $ do
+        let input = "f = (x : x)\nf 42"
         runTricu input @?= "Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) Leaf)))))"
 
-   , testCase "Lambda with a list literal" $ do
-        let input = "f = (\\x : x)\nf [t (t t)]"
+   , testCase "Lambda applied to list literal" $ do
+        let input = "f = (x : x)\nf [t (t t)]"
         runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
+
+  , testCase "Lambda containing list literal" $ do
+      let input = "(a : [(a)]) 1"
+      runTricu input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
   ]
 
-baseLibrary :: TestTree
-baseLibrary = testGroup "Library Tests"
-  [ testCase "K combinator 1" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "k (t) (t t)"
-          env = evalTricu library (parseTricu input)
-      result env @?= Leaf
-
-  , testCase "K combinator 2" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "k (t t) (t)"
-          env = evalTricu library (parseTricu input)
-      result env @?= Stem Leaf
-
-  , testCase "K combinator 3" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "k (t t t) (t)"
-          env = evalTricu library (parseTricu input)
-      result env @?= Fork Leaf Leaf
-
-  , testCase "S combinator" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "s (t) (t) (t)"
-          env = evalTricu library (parseTricu input)
-      result env @?= Fork Leaf (Stem Leaf)
-
-  , testCase "SKK == I (fully expanded)" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "s k k"
-          env = evalTricu library (parseTricu input)
-      result env @?= Fork (Stem (Stem Leaf)) (Stem Leaf)
-
-  , testCase "I combinator" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "i not?"
-          env = evalTricu library (parseTricu input)
-      result env @?= Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) (Fork Leaf (Fork Leaf Leaf))
-
-  , testCase "Triage test Leaf" $ do
-      library <- evaluateFile "./lib/base.tri"
+providedLibraries :: TestTree
+providedLibraries = testGroup "Library Tests"
+  [ testCase "Triage test Leaf" $ do
+      library <- evaluateFile "./lib/list.tri"
       let input = "test t"
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Leaf\""
 
   , testCase "Triage test (Stem Leaf)" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "test (t t)"
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Stem\""
 
   , testCase "Triage test (Fork Leaf Leaf)" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "test (t t t)"
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Fork\""
 
   , testCase "Boolean NOT: true" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? true"
           env = result $ evalTricu library (parseTricu input)
       env @?= Leaf
 
   , testCase "Boolean NOT: false" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? false"
           env = result $ evalTricu library (parseTricu input)
       env @?= Stem Leaf
 
 
   , testCase "Boolean AND TF" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
 
   , testCase "Boolean AND FT" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
 
   , testCase "Boolean AND FF" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
 
   , testCase "Boolean AND TT" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
 
   , testCase "List head" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "head [(t) (t t) (t t t)]"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
 
   , testCase "List tail" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "head (tail (tail [(t) (t t) (t t t)]))"
           env = evalTricu library (parseTricu input)
       result env @?= Fork Leaf Leaf
 
   , testCase "List map" $ do
-      library <- evaluateFile "./lib/base.tri"
-      let input = "head (tail (map (\\a : (t t t)) [(t) (t) (t)]))"
+      library <- evaluateFile "./lib/list.tri"
+      let input = "head (tail (map (a : (t t t)) [(t) (t) (t)]))"
           env = evalTricu library (parseTricu input)
       result env @?= Fork Leaf Leaf
 
   , testCase "Empty list check" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "emptyList? []"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
 
   , testCase "Non-empty list check" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? (emptyList? [(1) (2) (3)])"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
 
   , testCase "Concatenate strings" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "append \"Hello, \" \"world!\""
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Hello, world!\""
 
   , testCase "Verifying Equality" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "equal? (t t t) (t t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
@@ -490,12 +474,12 @@ fileEval = testGroup "File evaluation tests"
       res @?= Fork (Stem Leaf) Leaf
 
   , testCase "Mapping and Equality" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
+      library <- liftIO $ evaluateFile "./lib/list.tri"
       fEnv    <- liftIO $ evaluateFileWithContext library "./test/map.tri"
       (mainResult fEnv) @?= Stem Leaf
 
   , testCase "Eval and decoding string" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
+      library <- liftIO $ evaluateFile "./lib/list.tri"
       res <- liftIO $ evaluateFileWithContext library "./test/string.tri"
       decodeResult (result res) @?= "\"String test!\""
   ]
@@ -554,3 +538,35 @@ demos = testGroup "Test provided demo functionality"
       res     <- liftIO $ evaluateFileResult "./demos/levelOrderTraversal.tri"
       decodeResult res @?= "\"\n1 \n2 3 \n4 5 6 7 \n8 11 10 9 12 \""
   ]
+
+decoding :: TestTree
+decoding = testGroup "Decoding Tests"
+  [ testCase "Decode Leaf" $ do
+      decodeResult Leaf @?= "t"
+
+  , testCase "Decode list of non-ASCII numbers" $ do
+      let input = ofList [ofNumber 1, ofNumber 14, ofNumber 6]
+      decodeResult input @?= "[1, 14, 6]"
+
+  , testCase "Decode list of ASCII numbers as a string" $ do
+      let input = ofList [ofNumber 97, ofNumber 98, ofNumber 99]
+      decodeResult input @?= "\"abc\""
+
+  , testCase "Decode small number" $ do
+      decodeResult (ofNumber 42) @?= "42"
+
+  , testCase "Decode large number" $ do
+      decodeResult (ofNumber 9999) @?= "9999"
+
+  , testCase "Decode string in list" $ do
+      let input = ofList [ofString "hello", ofString "world"]
+      decodeResult input @?= "[\"hello\", \"world\"]"
+
+  , testCase "Decode mixed list with strings" $ do
+      let input = ofList [ofString "hello", ofNumber 42, ofString "world"]
+      decodeResult input @?= "[\"hello\", 42, \"world\"]"
+
+  , testCase "Decode nested lists with strings" $ do
+      let input = ofList [ofList [ofString "nested"], ofString "string"]
+      decodeResult input @?= "[[\"nested\"], \"string\"]"
+  ]

test/comments-1.tri

@@ -1,9 +1,9 @@
 -- This is a tricu comment!
 -- t (t t) (t (t t t))
 -- t (t t t) (t t)
--- x = (\a : a)
+-- x = (a : a)
 main = t (t t) t -- Fork (Stem Leaf) Leaf
 -- t t
 -- x
--- x = (\a : a)
+-- x = (a : a)
 -- t

test/cycle-1.tri

@@ -1,4 +1,4 @@
 
-!import "test/cycle-2.tri" Cycle2
+!import "cycle-2.tri" Cycle2
 
 cycle1 = t Cycle2.cycle2

test/cycle-2.tri

@@ -1,4 +1,4 @@
 
-!import "test/cycle-1.tri" Cycle1
+!import "cycle-1.tri" Cycle1
 
 cycle2 = t Cycle1.cycle1

test/lambda-A.tri

@@ -1 +1 @@
-main = (\x : x) t
+main = (x : x) t

test/local-ns/1.tri

@@ -1,4 +1,4 @@
 
-!import "test/local-ns/2.tri" Two
+!import "2.tri" Two
 
 main = Two.x

test/local-ns/2.tri

@@ -1,2 +1,2 @@
 
-!import "test/local-ns/3.tri" !Local
+!import "3.tri" !Local

test/local-ns/3.tri

@@ -1,2 +1 @@
-
 x = 3

test/map.tri

@@ -1,2 +1,2 @@
-x = map (\i : append "Successfully concatenated " i) [("two strings!")]
+x = map (i : append "Successfully concatenated " i) [("two strings!")]
 main = equal? x [("Successfully concatenated two strings!")]

test/multi-level-A.tri

@@ -1,2 +1,2 @@
-!import "./test/multi-level-B.tri" B
+!import "multi-level-B.tri" B
 main = B.main

test/multi-level-B.tri

@@ -1,2 +1,2 @@
-!import "./test/multi-level-C.tri" C
+!import "multi-level-C.tri" C
 main = C.val

test/namespace-A.tri

@@ -1,2 +1,2 @@
-!import "./test/namespace-B.tri" B
+!import "namespace-B.tri" B
 main = B.x

test/size.tri

@@ -1,21 +1,21 @@
-compose = \f g x : f (g x)
+compose = f g x : f (g x)
 
-succ = y (\self :
+succ = y (self :
   triage
     1
     t
     (triage
       (t (t t))
-      (\_ tail : t t (self tail))
+      (_ tail : t t (self tail))
       t))
 
-size = (\x :
-  (y (\self x :
+size = (x :
+  (y (self x :
     compose succ
       (triage
-        (\x : x)
+        (x : x)
         self
-        (\x y : compose (self x) (self y))
+        (x y : compose (self x) (self y))
         x)) x 0))
 
 size size

test/string.tri

@@ -1 +1 @@
-head (map (\i : append "String " i) [("test!")])
+head (map (i : append "String " i) [("test!")])

test/vars-A.tri

@@ -1,6 +1,6 @@
 
-!import "./test/vars-B.tri" B
+!import "vars-B.tri" B
 
-!import "./test/vars-C.tri" C
+!import "vars-C.tri" C
 
 main = B.y (C.z)

test/vars-B.tri

@@ -1 +1 @@
-y = \x : x
+y = x : x

tricu.cabal

@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           tricu
-version:        0.13.0
+version:        0.18.1
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co
@@ -27,10 +27,12 @@ executable tricu
     , cmdargs
     , containers
     , exceptions
+    , filepath
     , haskeline
     , megaparsec
     , mtl
     , text
+    , transformers
   other-modules:
     Eval
     FileEval
@@ -54,6 +56,7 @@ test-suite tricu-tests
     , cmdargs
     , containers
     , exceptions
+    , filepath
     , haskeline
     , megaparsec
     , mtl
@@ -61,6 +64,7 @@ test-suite tricu-tests
     , tasty-hunit
     , tasty-quickcheck
     , text
+    , transformers
   default-language:    Haskell2010
   other-modules:
     Eval