0.5.0 release commit

Additionally sorts gitignore and adds attempted decoding of lists back
to the REPL

.gitignore

@@ -1,14 +1,11 @@
-bin/
-data/Purr.sqlite
-data/encryptionKey
-/result
-/config.dhall
-/Dockerfile
-/docker-stack.yml
-.stack-work/
 *.swp
-dist*
+*.txt
 *~
 .env
+.stack-work/
+/Dockerfile
+/config.dhall
+/result
 WD
-*.hs.txt
+bin/
+dist*

README.md

@@ -1,18 +1,82 @@
-# sapling
+# tricu
 
-sapling is a "micro-language" that I'm working on to investigate [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) .
+## Introduction
 
-It offers a minimal amount of syntax sugar:
+tricu (pronounced like "tree-shoe" in English) is a purely functional interpreted language implemented in Haskell. [I'm](https://eversole.co) developing tricu to further research the possibilities offered by the various forms of [Tree Calculi](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf).
 
-- `t` operator behaving by the rules of Tree Calculus
-- Variable definitions
-- Lambda abstractions
-- List, Integer, and String literals
+tricu offers minimal syntax sugar yet manages to provide a complete, intuitive, and familiar programming environment. There is great power in simplicity. tricu offers:
 
-This is an active experimentation project by [someone who has no idea what they're doing](https://eversole.co).
+1. `t` operator behaving by the rules of Tree Calculus
+1. Function definitions/assignments
+1. Lambda abstractions eliminated to Tree Calculus forms
+1. List, Number, and String literals
+1. Parentheses for grouping function application
+
+These features move us cleanly out of the [turing tarpit](https://en.wikipedia.org/wiki/Turing_tarpit) territory that you may find yourself in if you try working only with the `t` operator.
+
+tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`. This project was named "sapling" until I discovered the name is already being used for other (completely unrelated) programming language development projects.
+
+## What does it look like?
+
+```
+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 : lconcat i " world!") [("Hello, ")])
+tricu > "Hello,  world!"
+tricu < id (head (map (\i : lconcat i " world!") [("Hello, ")]))
+tricu > "Hello,  world!"
+
+tricu < -- Intensionality! We can inspect the structure of a function.
+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 write a function to convert a function to source code
+tricu < toTString id
+tricu > "t (t (t t)) t"
+```
+
+## Installation and Use
+
+You can easily build and/or run this project using [Nix](https://nixos.org/download/).
+
+- Quick Start (REPL): 
+  - `nix run git+https://git.eversole.co/James/tricu`
+- Build executable in `./result/bin`: 
+  - `nix build git+https://git.eversole.co/James/tricu`
+
+`./result/bin/tricu --help`
+
+```
+tricu Evaluator and REPL
+
+tricu [COMMAND] ... [OPTIONS]
+  tricu: Exploring Tree Calculus
+
+Common flags:
+  -? --help       Display help message
+  -V --version    Print version information
+
+tricu [repl] [OPTIONS]
+  Start interactive REPL
+
+tricu eval [OPTIONS]
+  Evaluate tricu and return the result of the final expression.
+
+  -f --file=FILE  Input file path(s) for evaluation.
+                    Defaults to stdin.
+  -t --form=FORM  Optional output form: (tree|fsl|ast|ternary|ascii).
+                    Defaults to tricu-compatible `t` tree form.
+
+tricu decode [OPTIONS]
+  Decode a Tree Calculus value into a string representation.
+
+  -f --file=FILE  Optional input file path to attempt decoding.
+                    Defaults to stdin.
+```
 
 ## Acknowledgements 
 
 Tree Calculus was discovered by [Barry Jay](https://github.com/barry-jay-personal/blog). 
 
-[treecalcul.us](https://treecalcul.us) is an excellent website with an intuitive playground created by [Johannes Bader](https://johannes-bader.com/) that introduced me to Tree Calculus. If sapling sounds interesting but compiling this repo sounds like a hassle, you should check out his site.
+[treecalcul.us](https://treecalcul.us) is an excellent website with an intuitive playground created by [Johannes Bader](https://johannes-bader.com/) that introduced me to Tree Calculus. If tricu sounds interesting but compiling this repo sounds like a hassle, you should check out his site.

demos/LevelOrderTraversal.tri

@@ -0,0 +1,34 @@
+-- Level Order Traversal of a labelled binary tree
+-- Objective: Print each "level" of the tree on a separate line
+--
+-- NOTICE: This demo relies on tricu base library functions
+-- 
+-- We model labelled binary trees as sublists where values act as labels. We
+-- require explicit notation of empty nodes. Empty nodes can be represented 
+-- with an empty list, `[]`, which is equivalent to a single node `t`. 
+--
+-- Example tree inputs:
+-- [("1") [("2") [("4") t t] t] [("3") [("5") t t] [("6") t t]]]]
+-- Graph:
+--       1
+--      / \
+--     2   3
+--    /   /  \
+--   4   5    6
+--
+
+isLeaf = (\node : lOr (emptyList node) (emptyList (tail node)))
+getLabel = (\node : head node)
+getLeft = (\node : if (emptyList node) [] (if (emptyList (tail node)) [] (head (tail node))))
+getRight = (\node : if (emptyList node) [] (if (emptyList (tail node)) [] (if (emptyList (tail (tail node))) [] (head (tail (tail node))))))
+
+processLevel = y (\self queue : if (emptyList queue) [] (pair (map getLabel queue) (self (filter (\node : not (emptyList node)) (lconcat (map getLeft queue) (map getRight queue))))))
+levelOrderTraversal = (\a : processLevel (t a t))
+toLineString = y (\self levels : if (emptyList levels) "" (lconcat (lconcat (map (\x : lconcat x " ") (head levels)) "") (if (emptyList (tail levels)) "" (lconcat (t (t 10 t) t) (self (tail levels))))))
+levelOrderToString = (\s : toLineString (levelOrderTraversal s))
+
+flatten = foldl (\acc x : lconcat acc x) ""
+flatLOT = (\s : lconcat (t 10 t) (flatten (levelOrderToString s)))
+
+exampleOne = flatLOT [("1") [("2") [("4") t t] t] [("3") [("5") t t] [("6") t t]]]]
+exampleTwo = flatLOT [("1") [("2") [("4") [("8") t t] [("9") t t]] [("6") [("10") t t] [("12") t t]]] [("3") [("5") [("11") t t] t] [("7") t t]]]

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "sapling";
+  description = "tricu";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs";
@@ -10,7 +10,7 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs              = nixpkgs.legacyPackages.${system};
-        packageName       = "sapling";
+        packageName       = "tricu";
         containerPackageName = "${packageName}-container";
 
         customGHC = pkgs.haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
@@ -22,7 +22,7 @@
         enableSharedExecutables = false;
         enableSharedLibraries = false;
 
-        sapling = pkgs.haskell.lib.justStaticExecutables self.packages.${system}.default;
+        tricu = pkgs.haskell.lib.justStaticExecutables self.packages.${system}.default;
       in {
 
         packages.${packageName} =

lib/base.tri

@@ -0,0 +1,41 @@
+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)
+iC = (\a b c : s a (k c) b)
+iD = b (b iC) iC
+iE = b (b iD) iC
+yi = (\i : b m (c b (i m)))
+y = yi iC
+yC = yi iD
+yD = yi iE
+id = (\a : a)
+triage = (\a b c : t (t a b) c)
+pair = t
+matchBool = (\ot of : triage of (\_ : ot) (\_ _ : ot))
+matchList = (\oe oc : triage oe _ oc)
+matchPair = (\op : triage _ _ op)
+not = matchBool false true
+and = matchBool id (\z : false)
+if = (\cond then else : t (t else (t t then)) t cond)
+test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
+emptyList = matchList true (\y z : false)
+head = matchList t (\hd tl : hd)
+tail = matchList t (\hd tl : tl)
+lconcat = y (\self : matchList (\k : k) (\h r k : pair h (self r k)))
+lAnd = triage (\x : false) (\_ x : x) (\_ _ x : x)
+lOr = triage (\x : x) (\_ _ : true) (\_ _ x : true)
+hmap = y (\self : matchList (\f : t) (\hd tl f : pair (f hd) (self tl f)))
+map = (\f l : hmap l f)
+equal = y (\self : triage (triage true (\z : false) (\y z : false)) (\ax : triage false (self ax) (\y z : false)) (\ax ay : triage false (\z : false) (\bx by : lAnd (self ax bx) (self ay by))))
+hfilter = y (\self : matchList (\f : t) (\hd tl f : matchBool (t hd) i (f hd) (self tl f)))
+filter = (\f l : hfilter l f)
+hfoldl = y (\self f l x : matchList (\acc : acc) (\hd tl acc : self f tl (f acc hd)) l x)
+foldl  = (\f x l : hfoldl f l x)
+hfoldr = y (\self x f l : matchList x (\hd tl : f (self x f tl) hd) l)
+foldr  = (\f x l : hfoldr x f l)

shell.nix

@@ -1,8 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-let x = pkgs.haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
-		megaparsec
-  ]);
-in
-pkgs.mkShell {
-  buildInputs = [ x ];
-}

src/Eval.hs

@@ -2,139 +2,116 @@ module Eval where
 
 import Parser
 import Research
-import Data.Set (Set)
-import qualified Data.Set as Set
-import Data.List (foldl')
-import qualified Data.Map as Map
+
 import Data.Map  (Map)
 
-evalSingle :: Map.Map String T -> SaplingAST -> Map.Map String T
+import qualified Data.Map as Map
+import qualified Data.Set as Set
+
+evalSingle :: Map String T -> TricuAST -> Map String T
 evalSingle env term = case term of
   SFunc name [] body ->
+    let lineNoLambda = eliminateLambda body
+        result = evalAST env lineNoLambda
+    in Map.insert "__result" result (Map.insert name result env)
+  SLambda _ body ->
     let result = evalAST env body
-        in Map.insert name result env
-    SApp func arg ->
-        let result = apply (evalAST env func) (evalAST env arg)
     in Map.insert "__result" result env
-    SVar name -> case Map.lookup name env of
+  SApp func arg ->
+    let result = apply (evalAST env $ eliminateLambda func) (evalAST env $ eliminateLambda arg)
+    in Map.insert "__result" result env
+  SVar name ->
+    case Map.lookup name env of
       Just value -> Map.insert "__result" value env
-        Nothing -> error $ "Variable " ++ name ++ " not defined"
+      Nothing -> errorWithoutStackTrace $ "Variable " ++ name ++ " not defined"
   _ ->
     let result = evalAST env term
     in Map.insert "__result" result env
 
-evalSapling :: Map String T -> [SaplingAST] -> Map String T
-evalSapling env [] = env
-evalSapling env [lastLine] =
-    let
-        lastLineNoLambda = eliminateLambda lastLine
+evalTricu :: Map String T -> [TricuAST] -> Map String T
+evalTricu env list = evalTricu' env (filter (/= SEmpty) list)
+  where
+  evalTricu' :: Map String T -> [TricuAST] -> Map String T
+  evalTricu' env [] = env
+  evalTricu' env [lastLine] =
+    let lastLineNoLambda = eliminateLambda lastLine
         updatedEnv = evalSingle env lastLineNoLambda
     in Map.insert "__result" (result updatedEnv) updatedEnv
-evalSapling env (line:rest) =
-    let
-        lineNoLambda = eliminateLambda line
+  evalTricu' env (line:rest) =
+    let lineNoLambda = eliminateLambda line
         updatedEnv = evalSingle env lineNoLambda
-    in evalSapling updatedEnv rest
+    in evalTricu updatedEnv rest
 
-evalAST :: Map String T -> SaplingAST -> T
+evalAST :: Map String T -> TricuAST -> T
 evalAST env term = case term of
-    SVar name ->
-        case Map.lookup name env of
+  SVar name -> case Map.lookup name env of
     Just value -> value
-            Nothing -> error $ "Variable " ++ name ++ " not defined"
+    Nothing -> errorWithoutStackTrace $ "Variable " ++ name ++ " not defined"
   TLeaf -> Leaf
-    TStem t ->
-        Stem (evalAST env t)
-    TFork t1 t2 ->
-        Fork (evalAST env t1) (evalAST env t2)
-    SApp t1 t2 ->
-        apply (evalAST env t1) (evalAST env t2)
-    SStr str -> toString str
-    SInt num -> toNumber num
-    SList elems -> toList (map (evalAST Map.empty) elems)
+  TStem t -> Stem (evalAST env t)
+  TFork t1 t2 -> Fork (evalAST env t1) (evalAST env t2)
+  SApp t1 t2 -> apply (evalAST env t1) (evalAST env t2)
+  SStr str -> ofString str
+  SInt num -> ofNumber num
+  SList elems -> ofList (map (evalAST env) elems)
+  SEmpty -> Leaf
   SFunc name args body ->
-        error $ "Unexpected function definition " ++ name
-        ++ " in evalAST; define via evalSingle."
-    SLambda {} ->
-        error "Internal error: SLambda found in evalAST after elimination."
+    errorWithoutStackTrace $ "Unexpected function definition " ++ name
+  SLambda {} -> errorWithoutStackTrace "Internal error: SLambda found in evalAST after elimination."
 
-result :: Map String T -> T
-result r = case Map.lookup "__result" r of
-    Just a -> a
-    Nothing -> error "No __result field found in provided environment"
-
-
-eliminateLambda :: SaplingAST -> SaplingAST
+eliminateLambda :: TricuAST -> TricuAST
 eliminateLambda (SLambda (v:vs) body)
   | null vs = lambdaToT v (eliminateLambda body)
-    | otherwise =
-        eliminateLambda (SLambda [v] (SLambda vs body))
-eliminateLambda (SApp f arg) =
-    SApp (eliminateLambda f) (eliminateLambda arg)
-eliminateLambda (TStem t) =
-    TStem (eliminateLambda t)
-eliminateLambda (TFork l r) =
-    TFork (eliminateLambda l) (eliminateLambda r)
-eliminateLambda (SList xs) =
-    SList (map eliminateLambda xs)
-eliminateLambda (SFunc n vs b) =
-    SFunc n vs (eliminateLambda b)
+  | otherwise = eliminateLambda (SLambda [v] (SLambda vs body))
+eliminateLambda (SApp f arg) = SApp (eliminateLambda f) (eliminateLambda arg)
+eliminateLambda (TStem t) = TStem (eliminateLambda t)
+eliminateLambda (TFork l r) = TFork (eliminateLambda l) (eliminateLambda r)
+eliminateLambda (SList xs) = SList (map eliminateLambda xs)
 eliminateLambda other = other
 
-lambdaToT :: String -> SaplingAST -> SaplingAST
+-- https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf
+-- Chapter 4: Lambda-Abstraction
+lambdaToT :: String -> TricuAST -> TricuAST
 lambdaToT x (SVar y)
   | x == y = tI
 lambdaToT x (SVar y)
-    | x /= y =
-        SApp tK (SVar y)
+  | x /= y = SApp tK (SVar y)
 lambdaToT x t
-    | not (isFree x t) =
-        SApp tK t
+  | not (isFree x t) = SApp tK t
 lambdaToT x (SApp n u)
-    | not (isFree x (SApp n u)) =
-        SApp tK (SApp (eliminateLambda n) (eliminateLambda u))
-lambdaToT x (SApp n u) =
-    SApp
-    (SApp tS (lambdaToT x (eliminateLambda n)))
-    (lambdaToT x (eliminateLambda u))
-lambdaToT x (SApp f args) = lambdaToT x f
+  | not (isFree x (SApp n u)) = SApp tK (SApp (eliminateLambda n) (eliminateLambda u))
+lambdaToT x (SApp n u) = SApp (SApp tS (lambdaToT x (eliminateLambda n))) (lambdaToT x (eliminateLambda u))
 lambdaToT x body
-    | not (isFree x body) =
-        SApp tK body
-    | otherwise =
-        SApp
-        (SApp tS (lambdaToT x body))
-        tLeaf
+  | not (isFree x body) = SApp tK body
+  | otherwise = SApp (SApp tS (lambdaToT x body)) TLeaf
 
-tLeaf :: SaplingAST
-tLeaf = TLeaf
-
-freeVars :: SaplingAST -> Set String
+freeVars :: TricuAST -> Set.Set String
 freeVars (SVar v) = Set.singleton v
 freeVars (SInt _) = Set.empty
 freeVars (SStr _) = Set.empty
 freeVars (SList xs) = foldMap freeVars xs
-freeVars (SFunc _ _ b) = freeVars b
 freeVars (SApp f arg) = freeVars f <> freeVars arg
 freeVars TLeaf = Set.empty
+freeVars (SFunc _ _ b) = freeVars b
 freeVars (TStem t) = freeVars t
 freeVars (TFork l r) = freeVars l <> freeVars r
 freeVars (SLambda vs b) = foldr Set.delete (freeVars b) vs
 
-isFree :: String -> SaplingAST -> Bool
+isFree :: String -> TricuAST -> Bool
 isFree x = Set.member x . freeVars
 
-toAST :: T -> SaplingAST
-toAST Leaf = TLeaf
-toAST (Stem a) = TStem (toAST a)
-toAST (Fork a b) = TFork (toAST a) (toAST b)
+-- We need the SKI operators in an unevaluated TricuAST tree form so that we
+-- can keep the evaluation functions straightforward
+tI :: TricuAST
+tI = SApp (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf))) TLeaf
 
-tI :: SaplingAST
-tI = toAST _I
+tK :: TricuAST
+tK = SApp TLeaf TLeaf
 
-tK :: SaplingAST
-tK = toAST _K
-
-tS :: SaplingAST
-tS = toAST _S
+tS :: TricuAST
+tS = SApp (SApp TLeaf (SApp TLeaf (SApp (SApp TLeaf TLeaf) TLeaf))) TLeaf
 
+result :: Map String T -> T
+result r = case Map.lookup "__result" r of
+  Just a -> a
+  Nothing -> errorWithoutStackTrace "No __result field found in provided environment"

src/FileEval.hs

@@ -0,0 +1,30 @@
+module FileEval where
+
+import Eval
+import Parser
+import Research
+
+import System.IO
+
+import qualified Data.Map as Map
+
+evaluateFileResult :: FilePath -> IO T
+evaluateFileResult filePath = do
+  contents <- readFile filePath
+  let asts = parseTricu contents
+  let finalEnv = evalTricu Map.empty asts
+  case Map.lookup "__result" finalEnv of
+    Just finalResult -> return finalResult
+    Nothing -> errorWithoutStackTrace "No expressions to evaluate found"
+
+evaluateFile :: FilePath -> IO Env
+evaluateFile filePath = do
+  contents <- readFile filePath
+  let asts = parseTricu contents
+  pure $ evalTricu Map.empty asts
+
+evaluateFileWithContext :: Env -> FilePath -> IO Env
+evaluateFileWithContext env filePath = do
+  contents <- readFile filePath
+  let asts = parseTricu contents
+  pure $ evalTricu env asts

src/Lexer.hs

@@ -1,33 +1,25 @@
 module Lexer where
 
 import Research
-import Text.Megaparsec
-import Text.Megaparsec.Char
+
+import Control.Monad               (void)
 import Data.Void
+import Text.Megaparsec
+import Text.Megaparsec.Char hiding (space)
+import Text.Megaparsec.Char.Lexer
+
 import qualified Data.Set as Set
 
 type Lexer = Parsec Void String
-data LToken
-  = LKeywordT
-  | LIdentifier String
-  | LIntegerLiteral Int
-  | LStringLiteral String
-  | LAssign
-  | LColon
-  | LBackslash
-  | LOpenParen
-  | LCloseParen
-  | LOpenBracket
-  | LCloseBracket
-  | LNewline
-  deriving (Show, Eq, Ord)
 
 keywordT :: Lexer LToken
 keywordT = string "t" *> notFollowedBy alphaNumChar *> pure LKeywordT
 
 identifier :: Lexer LToken
 identifier = do
-  name <- some (letterChar <|> char '_' <|> char '-')
+  first <- letterChar <|> char '_'
+  rest <- many (letterChar <|> char '_' <|> char '-' <|> digitChar)
+  let name = first : rest
   if (name == "t" || name == "__result")
     then fail "Keywords (`t`, `__result`) cannot be used as an identifier"
     else return (LIdentifier name)
@@ -41,10 +33,7 @@ stringLiteral :: Lexer LToken
 stringLiteral = do
   char '"'
   content <- many (noneOf ['"'])
-  if null content
-    then fail "Empty string literals are not allowed"
-    else do
-      char '"' -- "
+  char '"' --"
   return (LStringLiteral content)
 
 assign :: Lexer LToken
@@ -72,10 +61,20 @@ lnewline :: Lexer LToken
 lnewline = char '\n' *> pure LNewline
 
 sc :: Lexer ()
-sc = skipMany (char ' ' <|> char '\t')
+sc = space space1 (skipLineComment "--") (skipBlockComment "|-" "-|")
 
-saplingLexer :: Lexer [LToken]
-saplingLexer = many (sc *> choice
+tricuLexer :: Lexer [LToken]
+tricuLexer = do
+  sc
+  tokens <- many $ do
+    tok <- choice tricuLexer'
+    sc
+    pure tok
+  sc
+  eof
+  pure tokens
+    where
+      tricuLexer' = 
         [ try identifier
         , try keywordT
         , try integerLiteral
@@ -87,10 +86,9 @@ saplingLexer = many (sc *> choice
         , closeParen
         , openBracket
         , closeBracket
-  , lnewline
-  ] <* sc) <* eof
+        ]
 
-lexSapling :: String -> [LToken]
-lexSapling input = case runParser saplingLexer "" input of
-  Left err  -> error $ "Lexical error:\n" ++ errorBundlePretty err
+lexTricu :: String -> [LToken]
+lexTricu input = case runParser tricuLexer "" input of
+  Left err -> errorWithoutStackTrace $ "Lexical error:\n" ++ errorBundlePretty err
   Right tokens -> tokens

src/Main.hs

@@ -1,13 +1,84 @@
 module Main where
 
-import Eval
-import Lexer
-import Parser
-import REPL (repl)
+import Eval                   (evalTricu, result)
+import FileEval
+import Parser                 (parseTricu)
+import REPL
 import Research
 
-import qualified Data.Map as Map
+import Control.Monad          (foldM)
+import Control.Monad.IO.Class (liftIO)
 import Text.Megaparsec        (runParser)
+import System.Console.CmdArgs
+
+import qualified Data.Map as Map
+
+data TricuArgs
+  = Repl
+  | Evaluate { file :: [FilePath], form :: EvaluatedForm }
+  | Decode { file :: [FilePath] }
+  deriving (Show, Data, Typeable)
+
+replMode :: TricuArgs
+replMode = Repl
+  &= help "Start interactive REPL"
+  &= auto
+  &= name "repl"
+
+evaluateMode :: TricuArgs
+evaluateMode = Evaluate
+  { file = def &= help "Input file path(s) for evaluation.\n \
+      \ Defaults to stdin."
+      &= name "f" &= typ "FILE"
+    , form = TreeCalculus &= typ "FORM"
+      &= help "Optional output form: (tree|fsl|ast|ternary|ascii).\n \
+      \ Defaults to tricu-compatible `t` tree form."
+      &= name "t"
+  }
+  &= help "Evaluate tricu and return the result of the final expression."
+  &= explicit
+  &= name "eval"
+
+decodeMode :: TricuArgs
+decodeMode = Decode
+  { file = def
+    &= help "Optional input file path to attempt decoding.\n \
+    \ Defaults to stdin."
+    &= name "f" &= typ "FILE"
+  }
+  &= help "Decode a Tree Calculus value into a string representation."
+  &= explicit
+  &= name "decode"
 
 main :: IO ()
-main = repl Map.empty --(Map.fromList [("__result", Leaf)])
+main = do
+  args <- cmdArgs $ modes [replMode, evaluateMode, decodeMode]
+    &= help "tricu: Exploring Tree Calculus"
+    &= program "tricu"
+    &= summary "tricu Evaluator and REPL"
+  case args of
+    Repl -> do
+      putStrLn "Welcome to the tricu REPL"
+      putStrLn "You can exit with `CTRL+D` or the `:_exit` command.`"
+      library <- liftIO $ evaluateFile "./lib/base.tri"
+      repl $ Map.delete "__result" library
+    Evaluate { file = filePaths, form = form } -> do
+      result <- case filePaths of
+        [] -> do
+          t <- getContents
+          pure $ runTricu t
+        (filePath:restFilePaths) -> do
+            initialEnv <- evaluateFile filePath
+            finalEnv <- foldM evaluateFileWithContext initialEnv restFilePaths
+            pure $ result finalEnv
+      let fRes = formatResult form result
+      putStr fRes
+    Decode { file = filePaths } -> do
+      value <- case filePaths of
+        [] -> getContents
+        (filePath:_) -> readFile filePath
+      library <- liftIO $ evaluateFile "./lib/base.tri"
+      putStrLn $ decodeResult $ result $ evalTricu library $ parseTricu value
+
+runTricu :: String -> T
+runTricu = result . evalTricu Map.empty . parseTricu

src/Parser.hs

@@ -1,57 +1,50 @@
 module Parser where
 
-import Debug.Trace
-
 import Lexer
 import Research hiding       (toList)
 
-import Control.Exception (throw)
 import Data.List.NonEmpty    (toList)
-import qualified Data.Set as Set
-import Data.Void
+import Data.Void (Void)
 import Text.Megaparsec
 import Text.Megaparsec.Char
-import Text.Megaparsec.Error (errorBundlePretty, ParseErrorBundle)
+import Text.Megaparsec.Error (ParseErrorBundle, errorBundlePretty)
+
+import qualified Data.Set as Set
 
 type Parser    = Parsec Void [LToken]
-data SaplingAST
-  = SVar    String
-  | SInt    Int
-  | SStr    String
-  | SList   [SaplingAST]
-  | SFunc   String       [String]     SaplingAST
-  | SApp    SaplingAST   SaplingAST
-  | TLeaf
-  | TStem   SaplingAST
-  | TFork   SaplingAST   SaplingAST
-  | SLambda [String]     SaplingAST
-  deriving (Show, Eq, Ord)
+type AltParser = Parsec Void String
 
-parseSapling :: String -> [SaplingAST]
-parseSapling input =
-  let nonEmptyLines = filter (not . null) (lines input)
-  in map parseSingle nonEmptyLines
+parseTricu :: String -> [TricuAST]
+parseTricu input
+  | null tokens = []
+  | otherwise = map parseSingle tokens
+  where
+    tokens = case lexTricu input of
+      [] -> []
+      tokens -> lines input
 
-parseSingle :: String -> SaplingAST
-parseSingle "" = error "Empty input provided to parseSingle"
-parseSingle input = case runParser parseExpression "" (lexSapling input) of
+parseSingle :: String -> TricuAST
+parseSingle input = case lexTricu input of
+  [] -> SEmpty
+  tokens -> case runParser parseExpression "" tokens of
     Left err -> error $ handleParseError err
     Right ast -> ast
 
-scnParser :: Parser ()
-scnParser = skipMany (satisfy isNewline)
-
-parseExpression :: Parser SaplingAST
+parseExpression :: Parser TricuAST
 parseExpression = choice
   [ try parseFunction
   , try parseLambda
+  , try parseLambdaExpression
   , try parseListLiteral
   , try parseApplication
   , try parseTreeTerm
   , parseLiteral
   ]
 
-parseFunction :: Parser SaplingAST
+scnParser :: Parser ()
+scnParser = skipMany (satisfy isNewline)
+
+parseFunction :: Parser TricuAST
 parseFunction = do
   LIdentifier name <- satisfy isIdentifier
   args <- many (satisfy isIdentifier)
@@ -59,7 +52,13 @@ parseFunction = do
   body <- parseExpression
   return (SFunc name (map getIdentifier args) body)
 
-parseLambda :: Parser SaplingAST
+parseAtomicBase :: Parser TricuAST
+parseAtomicBase = choice
+    [ parseTreeLeaf
+    , parseGrouped
+    ]
+
+parseLambda :: Parser TricuAST
 parseLambda = between (satisfy (== LOpenParen)) (satisfy (== LCloseParen)) $ do
   satisfy (== LBackslash)
   param    <- satisfy isIdentifier
@@ -69,54 +68,48 @@ parseLambda = between (satisfy (== LOpenParen)) (satisfy (== LCloseParen)) $ do
   let nestedLambda = foldr (\v acc -> SLambda [v] acc) body (map getIdentifier rest)
   return (SLambda [getIdentifier param] nestedLambda)
 
-parseLambdaExpression :: Parser SaplingAST
+parseLambdaExpression :: Parser TricuAST
 parseLambdaExpression = choice
   [ try parseLambdaApplication
   , parseAtomicLambda
   ]
 
-parseAtomicLambda :: Parser SaplingAST
+parseAtomicLambda :: Parser TricuAST
 parseAtomicLambda = choice
   [ parseVar
   , parseTreeLeaf
   , parseLiteral
   , parseListLiteral
+  , try parseLambda
   , between (satisfy (== LOpenParen)) (satisfy (== LCloseParen)) parseLambdaExpression
   ]
 
-parseApplication :: Parser SaplingAST
+parseApplication :: Parser TricuAST
 parseApplication = do
   func <- parseAtomicBase
   args <- many parseAtomic
   return $ foldl (\acc arg -> SApp acc arg) func args
 
-parseLambdaApplication :: Parser SaplingAST
+parseLambdaApplication :: Parser TricuAST
 parseLambdaApplication = do
   func <- parseAtomicLambda
   args <- many parseAtomicLambda
   return $ foldl (\acc arg -> SApp acc arg) func args
 
-isTreeTerm :: SaplingAST -> Bool
+isTreeTerm :: TricuAST -> Bool
 isTreeTerm TLeaf = True
 isTreeTerm (TStem _) = True
 isTreeTerm (TFork _ _) = True
 isTreeTerm _ = False
 
-parseAtomicBase :: Parser SaplingAST
-parseAtomicBase = choice
-  [ parseVar
-  , parseTreeLeaf
-  , parseGrouped
-  ]
-
-parseTreeLeaf :: Parser SaplingAST
+parseTreeLeaf :: Parser TricuAST
 parseTreeLeaf = satisfy isKeywordT *> notFollowedBy (satisfy (== LAssign)) *> pure TLeaf
 
 getIdentifier :: LToken -> String
 getIdentifier (LIdentifier name) = name
 getIdentifier _ = error "Expected identifier"
 
-parseTreeTerm :: Parser SaplingAST
+parseTreeTerm :: Parser TricuAST
 parseTreeTerm = do
   base <- parseTreeLeafOrParenthesized
   rest <- many parseTreeLeafOrParenthesized
@@ -127,18 +120,18 @@ parseTreeTerm = do
       TStem t -> TFork t next
       TFork _ _ -> TFork acc next
 
-parseTreeLeafOrParenthesized :: Parser SaplingAST
+parseTreeLeafOrParenthesized :: Parser TricuAST
 parseTreeLeafOrParenthesized = choice
   [ between (satisfy (== LOpenParen)) (satisfy (== LCloseParen)) parseTreeTerm
   , parseTreeLeaf
   ]
 
-foldTree :: [SaplingAST] -> SaplingAST
+foldTree :: [TricuAST] -> TricuAST
 foldTree [] = TLeaf
 foldTree [x] = x
 foldTree (x:y:rest) = TFork x (foldTree (y:rest))
 
-parseAtomic :: Parser SaplingAST
+parseAtomic :: Parser TricuAST
 parseAtomic = choice
   [ parseVar
   , parseTreeLeaf
@@ -147,45 +140,44 @@ parseAtomic = choice
   , parseLiteral
   ]
 
-
-parseGrouped :: Parser SaplingAST
+parseGrouped :: Parser TricuAST
 parseGrouped = between (satisfy (== LOpenParen)) (satisfy (== LCloseParen)) parseExpression
 
-parseLiteral :: Parser SaplingAST
+parseLiteral :: Parser TricuAST
 parseLiteral = choice
   [ parseIntLiteral
   , parseStrLiteral
   ]
 
-parens :: Parser SaplingAST -> Parser SaplingAST
+parens :: Parser TricuAST -> Parser TricuAST
 parens p = do
   satisfy (== LOpenParen)
   result <- p
   satisfy (== LCloseParen)
   return result
 
-parseListLiteral :: Parser SaplingAST
+parseListLiteral :: Parser TricuAST
 parseListLiteral = do
   satisfy (== LOpenBracket)
   elements <- many parseListItem
   satisfy (== LCloseBracket)
   return (SList elements)
 
-parseListItem :: Parser SaplingAST
+parseListItem :: Parser TricuAST
 parseListItem = choice
   [ parseGroupedItem
   , parseListLiteral
   , parseSingleItem
   ]
 
-parseGroupedItem :: Parser SaplingAST
+parseGroupedItem :: Parser TricuAST
 parseGroupedItem = do
   satisfy (== LOpenParen)
   inner <- parseExpression
   satisfy (== LCloseParen)
   return inner
 
-parseSingleItem :: Parser SaplingAST
+parseSingleItem :: Parser TricuAST
 parseSingleItem = do
   token <- satisfy isListItem
   case token of
@@ -198,19 +190,19 @@ isListItem (LIdentifier _) = True
 isListItem LKeywordT = True
 isListItem _ = False
 
-parseVar :: Parser SaplingAST
+parseVar :: Parser TricuAST
 parseVar = do
   LIdentifier name <- satisfy isIdentifier
   if (name == "t" || name == "__result")
     then fail $ "Reserved keyword: " ++ name ++ " cannot be assigned."
     else return (SVar name)
 
-parseIntLiteral :: Parser SaplingAST
+parseIntLiteral :: Parser TricuAST
 parseIntLiteral = do
   LIntegerLiteral value <- satisfy isIntegerLiteral
   return (SInt value)
 
-parseStrLiteral :: Parser SaplingAST
+parseStrLiteral :: Parser TricuAST
 parseStrLiteral = do
   LStringLiteral value <- satisfy isStringLiteral
   return (SStr value)
@@ -218,23 +210,54 @@ parseStrLiteral = do
 -- Boolean Helpers
 isKeywordT (LKeywordT) = True
 isKeywordT _ = False
-
 isIdentifier (LIdentifier _) = True
 isIdentifier _ = False
-
 isIntegerLiteral (LIntegerLiteral _) = True
 isIntegerLiteral _ = False
-
 isStringLiteral (LStringLiteral _) = True
 isStringLiteral _ = False
-
 isLiteral (LIntegerLiteral _) = True
 isLiteral (LStringLiteral _) = True
 isLiteral _ = False
-
-esNewline        (LNewline)          = True
+isNewline (LNewline) = True
 isNewline _ = False
 
+-- Alternative parsers
+altSC :: AltParser ()
+altSC = skipMany (char ' ' <|> char '\t' <|> char '\n')
+
+parseTernaryTerm :: AltParser TricuAST
+parseTernaryTerm = do
+  altSC
+  term <- choice parseTernaryTerm'
+  altSC
+  pure term
+  where
+    parseTernaryTerm' =
+      [ try (between (char '(') (char ')') parseTernaryTerm)
+      , try parseTernaryLeaf
+      , try parseTernaryStem
+      , try parseTernaryFork
+      ]
+
+parseTernaryLeaf :: AltParser TricuAST
+parseTernaryLeaf = char '0' *> pure TLeaf
+
+parseTernaryStem :: AltParser TricuAST
+parseTernaryStem = char '1' *> (TStem <$> parseTernaryTerm)
+
+parseTernaryFork :: AltParser TricuAST
+parseTernaryFork = do
+  char '2'
+  term1 <- parseTernaryTerm
+  term2 <- parseTernaryTerm
+  pure $ TFork term1 term2
+
+parseTernary :: String -> Either String TricuAST
+parseTernary input = case runParser (parseTernaryTerm <* eof) "" input of
+  Left err -> Left (errorBundlePretty err)
+  Right ast -> Right ast
+
 -- Error Handling
 handleParseError :: ParseErrorBundle [LToken] Void -> String
 handleParseError bundle =

src/REPL.hs

@@ -1,25 +1,71 @@
 module REPL where
 
 import Eval
+import FileEval
 import Lexer
 import Parser
 import Research
 
-import Control.Monad         (void)
-import qualified Data.Map as Map
-import System.IO            (hFlush, stdout)
+import Control.Exception         (SomeException, catch)
+import Control.Monad.IO.Class    (liftIO)
+import Data.Char                 (isSpace)
+import Data.List                 (dropWhile, dropWhileEnd, intercalate)
+import System.Console.Haskeline
 
-repl :: Map.Map String T -> IO ()
-repl env = do
-  putStr "sapling > "
-  hFlush stdout
-  input <- getLine
-  if input == "_:exit"
-    then putStrLn "Goodbye!"
-    else do
-      let clearEnv = Map.delete "__result" env
-      let newEnv   = evalSingle clearEnv (parseSingle input)
+import qualified Data.Map as Map
+
+repl :: Env -> IO ()
+repl env = runInputT defaultSettings (loop env)
+  where
+    loop :: Env -> InputT IO ()
+    loop env = do
+      minput <- getInputLine "tricu < "
+      case minput of
+        Nothing -> outputStrLn "Exiting tricu"
+        Just s -> case strip s of 
+          "!exit" -> outputStrLn "Exiting tricu"
+          "!load" -> do
+            path <- getInputLine "File path to load < "
+            case path of
+              Nothing -> do
+                outputStrLn "No input received; stopping import."
+                loop env
+              Just path -> do
+                loadedEnv <- liftIO $ evaluateFileWithContext env (strip path)
+                loop $ Map.delete "__result" (Map.union loadedEnv env)
+          "" -> do
+            outputStrLn ""
+            loop env
+          input -> do
+            case (take 2 input) of 
+              "--" -> loop env
+              _ -> do
+                newEnv <- liftIO $ (processInput env input `catch` errorHandler env)
+                loop newEnv
+  
+    processInput :: Env -> String -> IO Env
+    processInput env input = do
+      let asts = parseTricu input
+          newEnv = evalTricu env asts
       case Map.lookup "__result" newEnv of
-        Just r  -> putStrLn $ "sapling < " ++ show r
-        Nothing -> pure ()
-      repl newEnv
+        Just r -> do
+          putStrLn $ "tricu > " ++ decodeResult r
+        Nothing -> return ()
+      return newEnv
+    
+    errorHandler :: Env -> SomeException -> IO (Env)
+    errorHandler env e = do
+      putStrLn $ "Error: " ++ show e
+      return env
+    
+    strip :: String -> String
+    strip = dropWhileEnd isSpace . dropWhile isSpace
+
+decodeResult :: T -> String
+decodeResult tc = case toNumber tc of
+  Right num -> show num
+  Left _ -> case toString tc of
+    Right str -> "\"" ++ str ++ "\""
+    Left _ -> case toList tc of
+      Right list -> "[" ++ intercalate ", " (map decodeResult list) ++ "]"
+      Left _ -> formatResult TreeCalculus tc

src/Research.hs

@@ -1,13 +1,57 @@
 module Research where
 
-import Data.List (intercalate)
 import Control.Monad.State
-import qualified Data.Map as Map
+import Data.List                 (intercalate)
 import Data.Map                  (Map)
+import Data.Text                 (Text, replace)
+import System.Console.CmdArgs    (Data, Typeable)
 
+import qualified Data.Map        as Map
+import qualified Data.Text as T
+
+-- Tree Calculus Types
 data T = Leaf | Stem T | Fork T T
   deriving (Show, Eq, Ord)
 
+-- Abstract Syntax Tree for tricu
+data TricuAST
+  = SVar String
+  | SInt Int
+  | SStr String
+  | SList [TricuAST]
+  | SFunc String [String] TricuAST
+  | SApp TricuAST TricuAST
+  | TLeaf
+  | TStem TricuAST
+  | TFork TricuAST TricuAST
+  | SLambda [String] TricuAST
+  | SEmpty
+  deriving (Show, Eq, Ord)
+
+-- Tokens from Lexer
+data LToken
+  = LKeywordT
+  | LIdentifier String
+  | LIntegerLiteral Int
+  | LStringLiteral String
+  | LAssign
+  | LColon
+  | LBackslash
+  | LOpenParen
+  | LCloseParen
+  | LOpenBracket
+  | LCloseBracket
+  | LNewline
+  deriving (Show, Eq, Ord)
+
+-- Output formats
+data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii
+  deriving (Show, Data, Typeable)
+
+-- Environment containing previously evaluated TC terms
+type Env = Map.Map String T 
+
+-- Tree Calculus Reduction
 apply :: T -> T -> T
 apply Leaf b                            = Stem b
 apply (Stem a) b                        = Fork a b
@@ -17,16 +61,6 @@ 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
 
-reduce :: T -> T
-reduce expr =
-  let next = step expr
-  in if next == expr then expr else reduce next
-
-step :: T -> T
-step (Fork left right) = reduce (apply (reduce left) (reduce right))
-step (Stem inner) = Stem (reduce inner)
-step t = t
-
 -- SKI Combinators
 _S :: T
 _S = Fork (Stem (Fork Leaf Leaf)) Leaf
@@ -34,8 +68,11 @@ _S = Fork (Stem (Fork Leaf Leaf)) Leaf
 _K :: T
 _K = Stem Leaf
 
+-- Identity
+-- We use the "point-free" style which drops a redundant node
+-- Full I form (SKK): Fork (Stem (Stem Leaf)) (Stem Leaf)
 _I :: T
-_I = apply (apply _S _K) _K -- Fork (Stem (Stem Leaf)) (Stem Leaf)
+_I = Fork (Stem (Stem Leaf)) Leaf 
 
 -- Booleans
 _false :: T
@@ -48,35 +85,67 @@ _not :: T
 _not = Fork (Fork _true (Fork Leaf _false)) Leaf
 
 -- Marshalling
-toString :: String -> T
-toString str = toList (map toNumber (map fromEnum str))
+ofString :: String -> T
+ofString str = ofList (map ofNumber (map fromEnum str))
 
-ofString :: T -> String
-ofString tc = map (toEnum . ofNumber) (ofList tc)
-
-toNumber :: Int -> T
-toNumber 0 = Leaf
-toNumber n =
+ofNumber :: Int -> T
+ofNumber 0 = Leaf
+ofNumber n =
   Fork
     (if odd n then Stem Leaf else Leaf)
-    (toNumber (n `div` 2))
+    (ofNumber (n `div` 2))
 
-ofNumber :: T -> Int
-ofNumber Leaf = 0
-ofNumber (Fork Leaf rest) = 2 * ofNumber rest
-ofNumber (Fork (Stem Leaf) rest) = 1 + 2 * ofNumber rest
-ofNumber _ = error "Invalid Tree Calculus number"
+ofList :: [T] -> T
+ofList [] = Leaf
+ofList (x:xs) = Fork x (ofList xs)
 
-toList :: [T] -> T
-toList [] = Leaf
-toList (x:xs) = Fork x (toList xs)
+toNumber :: T -> Either String Int
+toNumber Leaf = Right 0
+toNumber (Fork Leaf rest) = case toNumber rest of
+  Right n -> Right (2 * n)
+  Left err -> Left err
+toNumber (Fork (Stem Leaf) rest) = case toNumber rest of
+  Right n -> Right (1 + 2 * n)
+  Left err -> Left err
+toNumber _ = Left "Invalid Tree Calculus number"
 
-ofList :: T -> [T]
-ofList Leaf = []
-ofList (Fork x rest) = x : ofList rest
-ofList _ = error "Invalid Tree Calculus list"
+toString :: T -> Either String String
+toString tc = case toList tc of
+  Right list -> traverse (fmap toEnum . toNumber) list
+  Left err -> Left "Invalid Tree Calculus string"
+
+toList :: T -> Either String [T]
+toList Leaf = Right []
+toList (Fork x rest) = case toList rest of
+  Right xs -> Right (x : xs)
+  Left err -> Left err
+toList _ = Left "Invalid Tree Calculus list"
+
+-- Outputs
+formatResult :: EvaluatedForm -> T -> String
+formatResult TreeCalculus = toSimpleT . show
+formatResult FSL          = show
+formatResult AST          = show . toAST
+formatResult Ternary      = toTernaryString
+formatResult Ascii        = toAscii
+
+toSimpleT :: String -> String
+toSimpleT s = T.unpack 
+  $ replace "Fork" "t"
+  $ replace "Stem" "t"
+  $ replace "Leaf" "t"
+  $ (T.pack s)
+
+toTernaryString :: T -> String
+toTernaryString Leaf = "0"
+toTernaryString (Stem t) = "1" ++ toTernaryString t
+toTernaryString (Fork t1 t2) = "2" ++ toTernaryString t1 ++ toTernaryString t2
+
+toAST :: T -> TricuAST
+toAST Leaf = TLeaf
+toAST (Stem a) = TStem (toAST a)
+toAST (Fork a b) = TFork (toAST a) (toAST b)
 
--- Utility
 toAscii :: T -> String
 toAscii tree = go tree "" True
   where
@@ -91,41 +160,4 @@ toAscii tree = go tree "" True
         ++ go left (prefix ++ (if isLast then "    " else "|   ")) False
         ++ go right (prefix ++ (if isLast then "    " else "|   ")) True
 
-rules :: IO ()
-rules = putStr $ header
-              ++ (unlines $ tcRules)
-              ++ (unlines $ haskellRules)
-              ++ footer
-  where
-    tcRules :: [String]
-    tcRules =
-      [ "|                                                                               |"
-      , "|                  ┌--------- | Tree Calculus | ---------┐                      |"
-      , "|                  | 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    |                      |"
-      , "|                  └-------------------------------------┘                      |"
-      , "|                                                                               |"
-      ]
-    haskellRules :: [String]
-    haskellRules =
-      [ "| ┌------------------------------ | Haskell | --------------------------------┐ |"
-      , "| |                                                                           | |"
-      , "| | data T = Leaf | Stem T | Fork TT                                          | |"
-      , "| |                                                                           | |"
-      , "| | apply :: T -> T -> 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            | |"
-      , "| └---------------------------------------------------------------------------┘ |"
-      ]
-    header :: String
-    header = "┌-------------------- | Rules for evaluating Tree Calculus | -------------------┐\n"
-    footer :: String
-    footer = "└-------------------- | Rules for evaluating Tree Calculus | -------------------┘\n"
+-- Utility

test/Spec.hs

@@ -1,25 +1,36 @@
 module Main where
 
 import Eval
+import FileEval
 import Lexer
 import Parser
+import REPL
 import Research
+
 import Control.Exception (evaluate, try, SomeException)
-import qualified Data.Map as Map
+import Control.Monad.IO.Class (liftIO)
 import Test.Tasty
 import Test.Tasty.HUnit
 import Test.Tasty.QuickCheck
 import Text.Megaparsec (runParser)
 
+import qualified Data.Map as Map
+import qualified Data.Set as Set
+
 main :: IO ()
 main = defaultMain tests
 
+runTricu :: String -> String
+runTricu s = show $ result (evalTricu Map.empty $ parseTricu s)
+
 tests :: TestTree
-tests = testGroup "Sapling Tests"
+tests = testGroup "Tricu Tests"
   [ lexerTests
   , parserTests
-    , integrationTests
   , evaluationTests
+  , lambdaEvalTests
+  , libraryTests
+  , fileEvaluationTests
   , propertyTests
   ]
 
@@ -28,131 +39,121 @@ lexerTests = testGroup "Lexer Tests"
   [ testCase "Lex simple identifiers" $ do
       let input = "x a b = a"
           expect = Right [LIdentifier "x", LIdentifier "a", LIdentifier "b", LAssign, LIdentifier "a"]
-        runParser saplingLexer "" input @?= expect
+      runParser tricuLexer "" input @?= expect
   , testCase "Lex Tree Calculus terms" $ do
       let input = "t t t"
           expect = Right [LKeywordT, LKeywordT, LKeywordT]
-        runParser saplingLexer "" input @?= expect
+      runParser tricuLexer "" input @?= expect
   , testCase "Lex escaped characters in strings" $ do
       let input = "\"hello\\nworld\""
           expect = Right [LStringLiteral "hello\\nworld"]
-        runParser saplingLexer "" input @?= expect
+      runParser tricuLexer "" input @?= expect
   , testCase "Lex mixed literals" $ do
       let input = "t \"string\" 42"
           expect = Right [LKeywordT, LStringLiteral "string", LIntegerLiteral 42]
-        runParser saplingLexer "" input @?= expect
+      runParser tricuLexer "" input @?= expect
   , testCase "Lex invalid token" $ do
-        let input = "$invalid"
-        case runParser saplingLexer "" input of
+      let input = "&invalid"
+      case runParser tricuLexer "" input of
         Left _ -> return ()
         Right _ -> assertFailure "Expected lexer to fail on invalid token"
   , testCase "Drop trailing whitespace in definitions" $ do
       let input = "x = 5 "
           expect = [LIdentifier "x",LAssign,LIntegerLiteral 5]
-        case (runParser saplingLexer "" input) of
+      case (runParser tricuLexer "" input) of
         Left _ -> assertFailure "Failed to lex input"
         Right i -> i @?= expect
   , testCase "Error when using invalid characters in identifiers" $ do
-        case (runParser saplingLexer "" "__result = 5") of
+        case (runParser tricuLexer "" "__result = 5") of
           Left _ -> return ()
           Right _ -> assertFailure "Expected failure when trying to assign the value of __result"
   ]
 
 parserTests :: TestTree
 parserTests = testGroup "Parser Tests"
-    [ testCase "Error when parsing incomplete definitions" $ do
-        let input = lexSapling "x = "
-        case (runParser parseExpression "" input) of
-            Left _ -> return ()
-            Right _ -> assertFailure "Expected failure on invalid input"
-    , testCase "Error when assigning a value to T" $ do
-        let input = lexSapling "t = x"
+  [ testCase "Error when assigning a value to T" $ do
+      let input = lexTricu "t = x"
       case (runParser parseExpression "" input) of
         Left _ -> return ()
         Right _ -> assertFailure "Expected failure when trying to assign the value of T"
-    , testCase "Error when parsing bodyless definitions with arguments" $ do
-        let input = lexSapling "x a b = "
-        case (runParser parseExpression "" input) of
-            Left _ -> return ()
-            Right _ -> assertFailure "Expected failure on invalid input"
   , testCase "Parse function definitions" $ do
-        let input = "x a b c = a"
-        let expect = SFunc "x" ["a","b","c"] (SVar "a")
+      let input = "x = (\\a b c : a)"
+          expect = SFunc "x" [] (SLambda ["a"] (SLambda ["b"] (SLambda ["c"] (SVar "a"))))
       parseSingle input @?= expect
   , testCase "Parse nested Tree Calculus terms" $ do
       let input = "t (t t) t"
-        let expect = SApp (SApp TLeaf (SApp TLeaf TLeaf)) TLeaf
+          expect = SApp (SApp TLeaf (SApp TLeaf TLeaf)) TLeaf
       parseSingle input @?= expect
   , testCase "Parse sequential Tree Calculus terms" $ do
       let input = "t t t"
-        let expect = SApp (SApp TLeaf TLeaf) TLeaf
+          expect = SApp (SApp TLeaf TLeaf) TLeaf
       parseSingle input @?= expect
   , testCase "Parse mixed list literals" $ do
       let input = "[t (\"hello\") t]"
-        let expect = SList [TLeaf, SStr "hello", TLeaf]
+          expect = SList [TLeaf, SStr "hello", TLeaf]
       parseSingle input @?= expect
   , testCase "Parse function with applications" $ do
-        let input = "f x = t x"
-        let expect = SFunc "f" ["x"] (SApp TLeaf (SVar "x"))
+      let input  = "f = (\\x : t x)"
+          expect = SFunc "f" [] (SLambda ["x"] (SApp TLeaf (SVar "x")))
       parseSingle input @?= expect
   , testCase "Parse nested lists" $ do
       let input  = "[t [(t t)]]"
-        let expect = SList [TLeaf,SList [SApp TLeaf TLeaf]]
+          expect = SList [TLeaf,SList [SApp TLeaf TLeaf]]
       parseSingle input @?= expect
   , testCase "Parse complex parentheses" $ do
       let input  = "t (t t (t t))"
-        let expect = SApp TLeaf (SApp (SApp TLeaf TLeaf) (SApp TLeaf TLeaf))
+          expect = SApp TLeaf (SApp (SApp TLeaf TLeaf) (SApp TLeaf TLeaf))
       parseSingle input @?= expect
   , testCase "Parse empty list" $ do
       let input  = "[]"
-        let expect = SList []
+          expect = SList []
       parseSingle input @?= expect
   , testCase "Parse multiple nested lists" $ do
       let input  = "[[t t] [t (t t)]]"
-        let expect = SList [SList [TLeaf,TLeaf],SList [TLeaf,SApp TLeaf TLeaf]]
+          expect = SList [SList [TLeaf,TLeaf],SList [TLeaf,SApp TLeaf TLeaf]]
       parseSingle input @?= expect
   , testCase "Parse whitespace variance" $ do
       let input1 = "[t t]"
       let input2 = "[ t t ]"
-        let expect = SList [TLeaf, TLeaf]
+          expect = SList [TLeaf, TLeaf]
       parseSingle input1 @?= expect
       parseSingle input2 @?= expect
   , testCase "Parse string in list" $ do
       let input  = "[(\"hello\")]"
-        let expect = SList [SStr "hello"]
+          expect = SList [SStr "hello"]
       parseSingle input @?= expect
   , testCase "Parse parentheses inside list" $ do
       let input  = "[t (t t)]"
-        let expect = SList [TLeaf,SApp TLeaf TLeaf]
+          expect = SList [TLeaf,SApp TLeaf TLeaf]
       parseSingle input @?= expect
   , testCase "Parse nested parentheses in function body" $ do
-        let input = "f = t (t (t t))"
-        let expect = SFunc "f" [] (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf)))
+      let input  = "f = (\\x : t (t (t t)))"
+          expect = SFunc "f" [] (SLambda ["x"] (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf))))
       parseSingle input @?= expect
   , testCase "Parse lambda abstractions" $ do
       let input  = "(\\a : a)"
-        let expect = (SLambda ["a"] (SVar "a"))
+          expect = (SLambda ["a"] (SVar "a"))
       parseSingle input @?= expect
   , testCase "Parse multiple arguments to lambda abstractions" $ do
       let input  = "x = (\\a b : a)"
-        let expect = SFunc "x" [] (SLambda ["a"] (SLambda ["b"] (SVar "a")))
+          expect = SFunc "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)\n" <> "x (t)"
+      let input  = "x = (\\a : a)\nx (t)"
           expect = [SFunc "x" [] (SLambda ["a"] (SVar "a")),SApp (SVar "x") TLeaf]
-        parseSapling input @?= expect
-    ]
-
-integrationTests :: TestTree
-integrationTests = testGroup "Integration Tests"
-    [ testCase "Combine lexer and parser" $ do
-        let input = "x = t t t"
-        let expect = SFunc "x" [] (SApp (SApp TLeaf TLeaf) TLeaf)
-        parseSingle input @?= expect
-    , testCase "Complex Tree Calculus expression" $ do
-        let input = "t (t t t) t"
-        let expect = SApp (SApp TLeaf (SApp (SApp TLeaf TLeaf) TLeaf)) TLeaf
-        parseSingle input @?= expect
+      parseTricu input @?= expect
+  , testCase "Comments 1" $ do
+      let input = "(t) (t) -- (t)"
+          expect = [SApp TLeaf TLeaf]
+      parseTricu input @?= expect
+  , testCase "Comments 2" $ do
+      let input = "(t) -- (t) -- (t)"
+          expect = [TLeaf]
+      parseTricu input @?= expect
+  , testCase "Comments with no terms" $ do
+      let input = unlines ["-- (t)", "(t t)"]
+          expect = [SEmpty,SApp TLeaf TLeaf]
+      parseTricu input @?= expect 
   ]
 
 evaluationTests :: TestTree
@@ -180,60 +181,244 @@ evaluationTests = testGroup "Evaluation Tests"
         Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
   , testCase "Environment updates with definitions" $ do
       let input = "x = t\ny = x"
-        let env = evalSapling Map.empty (parseSapling input)
+          env = evalTricu Map.empty (parseTricu input)
       Map.lookup "x" env @?= Just Leaf
       Map.lookup "y" env @?= Just Leaf
   , testCase "Variable substitution" $ do
       let input = "x = t t\ny = t x\ny"
-        let env = evalSapling Map.empty (parseSapling input)
+          env = evalTricu Map.empty (parseTricu input)
       (result env) @?= Stem (Stem Leaf)
   , testCase "Multiline input evaluation" $ do
       let input = "x = t\ny = t t\nx"
-        let env = evalSapling Map.empty (parseSapling input)
+          env = evalTricu Map.empty (parseTricu input)
       (result env) @?= Leaf
   , testCase "Evaluate string literal" $ do
       let input = "\"hello\""
       let ast = parseSingle input
-        (result $ evalSingle Map.empty ast) @?= toString "hello"
+      (result $ evalSingle Map.empty ast) @?= ofString "hello"
   , testCase "Evaluate list literal" $ do
       let input = "[t (t t)]"
       let ast = parseSingle input
-        (result $ evalSingle Map.empty ast) @?= toList [Leaf, Stem Leaf]
+      (result $ evalSingle Map.empty ast) @?= ofList [Leaf, Stem Leaf]
   , testCase "Evaluate empty list" $ do
       let input = "[]"
       let ast = parseSingle input
-        (result $ evalSingle Map.empty ast) @?= toList []
+      (result $ evalSingle Map.empty ast) @?= ofList []
   , testCase "Evaluate variable dependency chain" $ do
       let input = "x = t (t t)\n \
                   \ y = x\n \
                   \ z = y\n \
                   \ variablewithamuchlongername = z\n \
                   \ variablewithamuchlongername"
-        let env = evalSapling Map.empty (parseSapling input)
+          env = evalTricu Map.empty (parseTricu input)
       (result env) @?= (Stem (Stem Leaf))
   , testCase "Evaluate variable shadowing" $ do
       let input = "x = t t\nx = t\nx"
-        let env = evalSapling Map.empty (parseSapling input)
+          env = evalTricu Map.empty (parseTricu input)
       (result env) @?= Leaf
-    , testCase "Lambda identity" $ do
-        let input = "(\\a : a)"
-            env = evalSapling Map.empty (parseSapling input)
-        result env @?= Fork (Stem (Stem Leaf)) (Stem Leaf)
   , testCase "Apply identity to Boolean Not" $ do
       let not = "(t (t (t t) (t t t)) t)"
-            input = "x = (\\a : a)\nx " ++ not
-            env = evalSapling Map.empty (parseSapling input)
+      let input = "x = (\\a : a)\nx " ++ not
+          env = evalTricu Map.empty (parseTricu input)
       result env @?= Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
-    , testCase "Constant function matches" $ do
-        let input = "k = (\\a b : a)\nk (t t) t"
-            env = evalSapling Map.empty (parseSapling input)
+  ]
+
+lambdaEvalTests :: TestTree
+lambdaEvalTests = testGroup "Lambda Evaluation Tests"
+  [ testCase "Lambda Identity Function" $ do
+      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)"
+      runTricu input @?= "Leaf"
+  , testCase "Lambda Application with Variable" $ do
+      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)"
+      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"
+      runTricu input @?= "Leaf"
+  , testCase "Lambda with a complex body" $ do
+      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)"
+      runTricu input @?= "Leaf"
+  , testCase "Lambda with Shadowing" $ do
+      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)"
+      runTricu input @?= "Leaf"
+   , testCase "Lambda with free variables" $ do
+      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)"
+      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)"
+      runTricu input @?= "Stem Leaf"
+   , testCase "Lambda with nested application in the body" $ do
+      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)"
+        runTricu input @?= "Fork Leaf (Stem Leaf)"
+    , testCase "Lambda applying a variable" $ do
+        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"
+        runTricu input @?= "Leaf"
+  , testCase "Lambda with a 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"
+        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)]"
+        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
+  ]
+
+libraryTests :: TestTree
+libraryTests = 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"
+      let input = "test t"
+          env = decodeResult $ result $ evalTricu library (parseTricu input)
+      env @?= "\"Leaf\""
+  , testCase "Triage test (Stem Leaf)" $ do
+      library <- evaluateFile "./lib/base.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"
+      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"
+      let input = "not true"
+          env = result $ evalTricu library (parseTricu input)
+      env @?= Leaf
+  , testCase "Boolean NOT: false" $ do
+      library <- evaluateFile "./lib/base.tri"
+      let input = "not false"
+          env = result $ evalTricu library (parseTricu input)
+      env @?= Stem Leaf
+  , testCase "Boolean AND TF" $ do
+      library <- evaluateFile "./lib/base.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"
+      let input = "and (t) (t t)"
+          env = evalTricu library (parseTricu input)
+      result env @?= Leaf
+  , testCase "Boolean AND FF" $ do
+      library <- evaluateFile "./lib/base.tri"
+      let input = "and (t) (t)"
+          env = evalTricu library (parseTricu input)
+      result env @?= Leaf
+  , testCase "Boolean AND TT" $ do
+      library <- evaluateFile "./lib/base.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"
+      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"
+      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)]))"
+          env = evalTricu library (parseTricu input)
+      result env @?= Fork Leaf Leaf
+  , testCase "Empty list check" $ do
+      library <- evaluateFile "./lib/base.tri"
+      let input = "emptyList []"
+          env = evalTricu library (parseTricu input)
+      result env @?= Stem Leaf
+  , testCase "Non-empty list check" $ do
+      library <- evaluateFile "./lib/base.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"
+      let input = "lconcat \"Hello, \" \"world!\""
+          env = decodeResult $ result $ evalTricu library (parseTricu input)
+      env @?= "\"Hello, world!\""
+  , testCase "Verifying Equality" $ do
+      library <- evaluateFile "./lib/base.tri"
+      let input = "equal (t t t) (t t t)"
+          env = evalTricu library (parseTricu input)
+      result env @?= Stem Leaf
+  ]
+
+fileEvaluationTests :: TestTree
+fileEvaluationTests = testGroup "Evaluation tests"
+  [ testCase "Forks" $ do
+      res <- liftIO $ evaluateFileResult "./test/fork.tri"
+      res @?= Fork Leaf Leaf
+  , testCase "File ends with comment" $ do
+      res <- liftIO $ evaluateFileResult "./test/comments-1.tri"
+      res @?= Fork (Stem Leaf) Leaf
+  , testCase "Mapping and Equality" $ do
+      res <- liftIO $ evaluateFileResult "./test/map.tri"
+      res @?= Stem Leaf
+  , testCase "Eval and decoding string" $ do
+      library <- liftIO $ evaluateFile "./lib/base.tri"
+      res <- liftIO $ evaluateFileWithContext library "./test/string.tri"
+      decodeResult (result res) @?= "\"String test!\""
   ]
 
 propertyTests :: TestTree
 propertyTests = testGroup "Property Tests"
   [ testProperty "Lexing and parsing round-trip" $ \input ->
-        case runParser saplingLexer "" input of
+      case runParser tricuLexer "" input of
         Left _ -> property True
         Right tokens -> case runParser parseExpression "" tokens of
           Left _ -> property True

test/ascii.tri

@@ -0,0 +1 @@
+t (t (t (t (t t) (t t t)) t) t t) t

test/assignment.tri

@@ -0,0 +1 @@
+x = t (t t) t

test/comments-1.tri

@@ -0,0 +1,9 @@
+-- This is a tricu comment!
+-- t (t t) (t (t t t))
+-- t (t t t) (t t)
+-- x = (\a : a)
+t (t t) t -- Fork (Stem Leaf) Leaf
+-- t t
+-- x
+-- x = (\a : a)
+-- t

test/fork.tri

@@ -0,0 +1 @@
+t t t 

test/map.tri

@@ -0,0 +1,24 @@
+false = t
+true = t 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)
+iC = (\a b c : s a (k c) b)
+yi = (\i : b m (c b (i m)))
+y = yi iC
+triage = (\a b c : t (t a b) c)
+pair = t
+matchList = (\oe oc : triage oe _ oc)
+lconcat = y (\self : matchList (\k : k) (\h r k : pair h (self r k)))
+hmap = y (\self : matchList (\f : t) (\hd tl f : pair (f hd) (self tl f)))
+map = (\f l : hmap l f)
+lAnd = triage (\x : false) (\_ x : x) (\_ _ x : x)
+lOr = triage (\x : x) (\_ _ : true) (\_ _ x : true)
+equal = y (\self : triage (triage true (\z : false) (\y z : false)) (\ax : triage false (self ax) (\y z : false)) (\ax ay : triage false (\z : false) (\bx by : lAnd (self ax bx) (self ay by))))
+
+x = map (\i : lconcat "Successfully concatenated " i) [("two strings!")]
+equal x [("Successfully concatenated two strings!")]

test/string.tri

@@ -0,0 +1 @@
+head (map (\i : lconcat "String " i) [("test!")])

tricu.cabal

@@ -1,8 +1,8 @@
 cabal-version: 1.12
 
-name:           sapling
-version:        0.2.0
-description:    Tree Calculus experiment repository
+name:           tricu
+version:        0.5.0
+description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co
 copyright:      James Eversole
@@ -12,48 +12,53 @@ build-type:     Simple
 extra-source-files:
     README.md
 
-executable sapling
+executable tricu
   main-is: Main.hs
   hs-source-dirs:
       src
   default-extensions:
-      ConstraintKinds
-      DataKinds
-      DeriveGeneric
-      FlexibleContexts
-      FlexibleInstances
-      GeneralizedNewtypeDeriving
+      DeriveDataTypeable
       OverloadedStrings
-      ScopedTypeVariables
   ghc-options: -threaded -rtsopts -with-rtsopts=-N -optl-pthread -fPIC
   build-depends:
     base >=4.7
+    , cmdargs
     , containers
+    , haskeline
     , megaparsec
     , mtl
+    , text
   other-modules:
     Eval
+    FileEval
     Lexer
     Parser
     REPL
     Research
   default-language: Haskell2010
 
-test-suite sapling-tests
+test-suite tricu-tests
   type:                exitcode-stdio-1.0
   main-is:             Spec.hs
   hs-source-dirs:      test, src
+  default-extensions:
+      DeriveDataTypeable
+      OverloadedStrings
   build-depends:       
     base
+    , cmdargs
     , containers
+    , haskeline
     , megaparsec
     , mtl
     , tasty
     , tasty-hunit
     , tasty-quickcheck
+    , text
   default-language:    Haskell2010
   other-modules:
     Eval
+    FileEval
     Lexer
     Parser
     REPL