47 changed files with 572 additions and 890 deletions
--- a/.gitignore
+++ b/.gitignore
@ -9,4 +9,3 @@
 WD
 bin/
 dist*
-.tricu_history
--- a/README.md
+++ b/README.md
@ -2,20 +2,19 @@

 ## Introduction

-tricu (pronounced "tree-shoe") is a purely functional interpreted language implemented in Haskell. It is fundamentally based on the application of [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) terms, but minimal syntax sugar is included to provide a useful programming tool. 
-
-*tricu is under active development and you should expect breaking changes with every commit.*
+tricu (pronounced "tree-shoe") is a purely functional interpreted language implemented in Haskell. It is fundamentally based on the application of [Tree Calculus](https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf) terms, but minimal syntax sugar is included to provide a useful programming tool. tricu is under active development and you can expect breaking changes with nearly every commit.

 tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`.

 ## Features

 - Tree Calculus operator: `t`
- Immutable definitions: `x = t t`
- Lambda abstraction: `id = (a : a)`
+- Assignments: `x = t t`
+- Immutable definitions
+- Lambda abstraction syntax: `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 : lconcat a "!") [("Hello")]`
 - Intensionality blurs the distinction between functions and data (see REPL examples)
 - Simple module system for code organization

@ -23,15 +22,15 @@ 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 : lconcat i " world!") [("Hello, ")])
 tricu > "Hello,  world!"
-tricu < id (head (map (i : append i " world!") [("Hello, ")]))
+tricu < id (head (map (\i : lconcat 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)
@ -40,21 +39,13 @@ 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

-You can easily build and run this project using [Nix](https://nixos.org/download/).
+[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/).

 - Quick Start (REPL): 
  - `nix run git+https://git.eversole.co/James/tricu`
@ -91,12 +82,6 @@ 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). 
--- a/demos/equality.tri
+++ b/demos/equality.tri
@ -1,5 +1,6 @@
-!import "../lib/base.tri" !Local
-!import "../lib/list.tri" !Local
+!module Equality
+
+!import "lib/base.tri" Lib

 main = lambdaEqualsTC

@ -11,20 +12,23 @@ 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 = a b : demo_triage b (_ : a) (_ _ : a)
-
+demo_triage = \a b c : t (t a b) c
+demo_matchBool = (\ot of : demo_triage
+  of
+  (\_ : ot)
+  (\_ _ : ot)
+)
 -- Lambda representation of the Boolean `not` function
 not_Lambda? = demo_matchBool demo_false demo_true

-- As tricu eliminates Lambda terms to SKI combinators, the tree form of many
+-- Since 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 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.
+-- 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.

 -- Let's see if these are the same:
-lambdaEqualsTC = equal? not_TC? not_Lambda?
+lambdaEqualsTC = Lib.equal? not_TC? not_Lambda?

 -- Here are some checks to verify their extensional behavior is the same:
 true_TC?  = not_TC? demo_false
@ -33,5 +37,5 @@ false_TC? = not_TC? demo_true
 true_Lambda?  = not_Lambda? demo_false
 false_Lambda? = not_Lambda? demo_true

-bothTrueEqual?  = equal? true_TC?  true_Lambda?
-bothFalseEqual? = equal? false_TC? false_Lambda?
+bothTrueEqual?  = Lib.equal? true_TC?  true_Lambda?
+bothFalseEqual? = Lib.equal? false_TC? false_Lambda?
--- a/demos/levelOrderTraversal.tri
+++ b/demos/levelOrderTraversal.tri
@ -1,5 +1,6 @@
-!import "../lib/base.tri" Lib
-!import "../lib/list.tri" !Local
+!module LOT
+
+!import "lib/base.tri" Lib

 main = exampleTwo
 -- Level Order Traversal of a labelled binary tree
@ -18,47 +19,47 @@ main = exampleTwo
 --    /   /  \
 --   4   5    6

-label = node : head node
+label = \node : Lib.head node

-left = node : (if (emptyList? node)
-  []
-  (if (emptyList? (tail node))
-    []
-    (head (tail node))))
+left = (\node : Lib.if (Lib.emptyList? node)
+  [] 
+  (Lib.if (Lib.emptyList? (Lib.tail node)) 
+    [] 
+    (Lib.head (Lib.tail node))))

-right = node : (if (emptyList? node)
-  []
-  (if (emptyList? (tail node))
-    []
-    (if (emptyList? (tail (tail node)))
-      []
-      (head (tail (tail node))))))
+right = (\node : Lib.if (Lib.emptyList? node) 
+  [] 
+  (Lib.if (Lib.emptyList? (Lib.tail node)) 
+    [] 
+    (Lib.if (Lib.emptyList? (Lib.tail (Lib.tail node))) 
+      [] 
+      (Lib.head (Lib.tail (Lib.tail node))))))

-processLevel = y (self queue : if (emptyList? queue)
-  []
-  (pair (map label queue) (self (filter
-    (node : not? (emptyList? node))
-      (append (map left queue) (map right queue))))))
+processLevel = Lib.y (\self queue : Lib.if (Lib.emptyList? queue) 
+  [] 
+  (Lib.pair (Lib.map label queue) (self (Lib.filter 
+    (\node : Lib.not? (Lib.emptyList? node)) 
+      (Lib.lconcat (Lib.map left queue) (Lib.map right queue))))))

-levelOrderTraversal_ = a : processLevel (t a t)
+levelOrderTraversal_ = \a : processLevel (t a t)

-toLineString = y (self levels : if (emptyList? levels)
-  ""
-  (append
-    (append (map (x : append x " ") (head levels)) "")
-    (if (emptyList? (tail levels)) "" (append (t (t 10 t) t) (self (tail levels))))))
+toLineString = Lib.y (\self levels : Lib.if (Lib.emptyList? levels) 
+  "" 
+  (Lib.lconcat 
+    (Lib.lconcat (Lib.map (\x : Lib.lconcat x " ") (Lib.head levels)) "") 
+    (Lib.if (Lib.emptyList? (Lib.tail levels)) "" (Lib.lconcat (t (t 10 t) t) (self (Lib.tail levels))))))

-levelOrderToString = s : toLineString (levelOrderTraversal_ s)
+levelOrderToString = \s : toLineString (levelOrderTraversal_ s)

-flatten = foldl (acc x : append acc x) ""
+flatten = Lib.foldl (\acc x : Lib.lconcat acc x) ""

-levelOrderTraversal = s : append (t 10 t) (flatten (levelOrderToString s))
+levelOrderTraversal = \s : Lib.lconcat (t 10 t) (flatten (levelOrderToString s))

-exampleOne = levelOrderTraversal [("1")
-                                 [("2") [("4") t t] t]
+exampleOne = levelOrderTraversal [("1") 
+                                 [("2") [("4") t t] t] 
                                 [("3") [("5") t t] [("6") t t]]]

-exampleTwo = levelOrderTraversal [("1")
-                                 [("2") [("4") [("8") t t] [("9") t t]]
-                                        [("6") [("10") t t] [("12") t t]]]
+exampleTwo = levelOrderTraversal [("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]]]
--- a/demos/patternMatching.tri
+++ b/demos/patternMatching.tri
@ -1,37 +0,0 @@
-!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!"
--- a/demos/size.tri
+++ b/demos/size.tri
@ -1,11 +1,25 @@
-!import "../lib/base.tri" !Local
-!import "../lib/list.tri" !Local
+!module Size
+
+!import "lib/base.tri" Lib

 main = size size

-size = x : y (self x : compose succ (triage
-  id
-  self
-  (x y : compose (self x) (self y))
-  x)
-) x 0
+compose = \f g x : f (g x)
+
+succ = Lib.y (\self :
+  Lib.triage
+    1
+    t
+    (Lib.triage
+      (t (t t))
+      (\_ Lib.tail : t t (self Lib.tail))
+      t))
+
+size = (\x :
+  (Lib.y (\self x :
+    compose succ
+      (Lib.triage
+        (\x : x)
+        self
+        (\x y : compose (self x) (self y))
+        x)) x 0))
--- a/demos/toSource.tri
+++ b/demos/toSource.tri
@ -1,7 +1,8 @@
-!import "../lib/base.tri" !Local
-!import "../lib/list.tri" !Local
+!module ToSource

-main = toSource not?
+!import "lib/base.tri" Lib
+
+main = toSource Lib.not?
 -- Thanks to intensionality, we can inspect the structure of a given value
 -- even if it's a function. This includes lambdas which are eliminated to
 -- Tree Calculus (TC) terms during evaluation.
@ -15,36 +16,36 @@ main = toSource not?
 -- triage = (\leaf stem fork : t (t leaf stem) fork)

 -- Base case of a single Leaf
-sourceLeaf = t (head "t")
+sourceLeaf = t (Lib.head "t")

 -- Stem case
-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.
+sourceStem = (\convert : (\a rest :
+  t (Lib.head "(")                       -- Start with a left parenthesis "(".
+    (t (Lib.head "t")                    -- Add a "t"
+      (t (Lib.head " ")                  -- Add a space.
+        (convert a                       -- Recursively convert the argument.
+          (t (Lib.head ")") rest))))))   -- Close with ")" and append the rest.

 -- Fork case
-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.
+sourceFork = (\convert : (\a b rest :
+  t (Lib.head "(")                           -- Start with a left parenthesis "(".
+    (t (Lib.head "t")                        -- Add a "t"
+      (t (Lib.head " ")                      -- Add a space.
+        (convert a                           -- Recursively convert the first arg.
+          (t (Lib.head " ")                  -- Add another space.
+            (convert b                       -- Recursively convert the second arg.
+              (t (Lib.head ")") rest)))))))) -- Close with ")" and append the rest.

 -- Wrapper around triage 
-toSource_ = y (self arg :
-  triage
+toSource_ = Lib.y (\self arg :
+  Lib.triage
    sourceLeaf        -- `triage` "a" case, Leaf
    (sourceStem self) -- `triage` "b" case, Stem
    (sourceFork self) -- `triage` "c" case, Fork
    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)))"
+exampleOne = toSource Lib.true -- OUT: "(t t)"
+exampleTwo = toSource Lib.not? -- OUT: "(t (t (t t) (t t t)) (t t (t t t)))"
--- a/flake.nix
+++ b/flake.nix
@ -34,7 +34,6 @@
        devShells.default = pkgs.mkShell {
          buildInputs = with pkgs; [
            haskellPackages.cabal-install
-            haskellPackages.ghc-events
            haskellPackages.ghcid
            customGHC
            upx
--- a/lib/base.tri
+++ b/lib/base.tri
@ -1,74 +1,83 @@
 false = t
 _     = t
 true  = t t
-id    = a : a
-const = a b : a
+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
 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)
+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)
 )

-lAnd = (triage
-  (_     : false)
-  (_ x   : x)
-  (_ _ x : x))
+matchList = \a b : triage a _ b

-lOr = (triage
-  (x     : x)
-  (_ _   : true)
-  (_ _ _ : true))
-
-matchPair = a : triage _ _ a
+matchPair = \a   : triage _ _ a

 not? = matchBool false true
-and? = matchBool id (_ : false)
+and? = matchBool id (\_ : false)
+emptyList? = matchList true (\_ _ : false)

-or? = (x z : 
-  matchBool 
-    (matchBool true true z)
-    (matchBool true false z)
-    x)
+head = matchList t (\head _ : head)
+tail = matchList t (\_ tail : tail)

-xor? = (x z : 
-  matchBool 
-    (matchBool false true z)
-    (matchBool true false z)
-    x)
+lconcat = y (\self : matchList
+  (\k : k)
+  (\h r k : pair h (self r k)))

-equal? = y (self : triage
+lAnd = (triage
+  (\_     : false)
+  (\_ x   : x)
+  (\_ _ x : x))
+
+lOr = (triage
+  (\x     : x)
+  (\_ _   : true)
+  (\_ _ _ : true))
+
+map_ = y (\self :
+  matchList
+    (\_ : t)
+    (\head tail f : pair (f head) (self tail f)))
+map = \f l : map_ l f
+
+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))))

-succ = y (self :
-  triage
-    1
-    t
-    (triage
-      (t (t t))
-      (_ tail : t t (self tail))
-      t))
+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
--- a/lib/list.tri
+++ b/lib/list.tri
@ -1,70 +0,0 @@
-!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
--- a/lib/patterns.tri
+++ b/lib/patterns.tri
@ -1,24 +0,0 @@
-!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)
--- a/src/Eval.hs
+++ b/src/Eval.hs
@ -15,20 +15,20 @@ evalSingle env term
      Just existingValue
        | existingValue == evalAST env body -> env
        | otherwise -> errorWithoutStackTrace $
-            "Unable to rebind immutable identifier: " ++ name
+            "Unable to rebind immutable identifier: '" ++ name
      Nothing ->
        let res = evalAST env body
        in Map.insert "!result" res (Map.insert name res env)
-  | SApp func arg <- term
+  | SApp func arg <- term 
  = let res = apply (evalAST env func) (evalAST env arg)
      in Map.insert "!result" res env
-  | SVar name <- term
+  | SVar name <- term 
  = case Map.lookup name env of
        Just v  -> Map.insert "!result" v env
        Nothing ->
          errorWithoutStackTrace $ "Variable `" ++ name ++ "` not defined\n\
          \This error should never occur here. Please report this as an issue."
-  | otherwise
+  | otherwise 
  = Map.insert "!result" (evalAST env term) env

 evalTricu :: Env -> [TricuAST] -> Env
@ -70,14 +70,13 @@ elimLambda = go
      | body == triageBody         = _TRIAGE
      where
        triageBody =
-          SApp (SApp TLeaf (SApp (SApp TLeaf (SVar a)) (SVar b))) (SVar c)
+          (SApp (SApp TLeaf (SApp (SApp TLeaf (SVar a)) (SVar b))) (SVar c))
    -- Composition optimization
    go (SLambda [f] (SLambda [g] (SLambda [x] body)))
-      | body == SApp (SVar f) (SApp (SVar g) (SVar x)) = _B
+      | body == composeBody        = _COMPOSE
+      where
+        composeBody = SApp (SVar f) (SApp (SVar g) (SVar x))
    -- 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))
@ -97,8 +96,8 @@ elimLambda = go
    _S       = parseSingle "t (t (t t t)) t"
    _K       = parseSingle "t t"
    _I       = parseSingle "t (t (t t)) t"
-    _B       = parseSingle "t (t (t t (t (t (t t t)) t))) (t t)"
    _TRIAGE  = parseSingle "t (t (t t (t (t (t t t))))) t"
+    _COMPOSE = parseSingle "t (t (t t (t (t (t t t)) t))) (t t)"

 isFree :: String -> TricuAST -> Bool
 isFree x = Set.member x . freeVars
@ -109,12 +108,12 @@ freeVars (SInt    _    ) = Set.empty
 freeVars (SStr    _    ) = Set.empty
 freeVars (SList   s    ) = foldMap freeVars s
 freeVars (SApp    f a  ) = freeVars f <> freeVars a
-freeVars  TLeaf          = Set.empty
+freeVars (TLeaf        ) = Set.empty
 freeVars (SDef   _ _ b)  = freeVars b
 freeVars (TStem   t    ) = freeVars t
 freeVars (TFork   l r  ) = freeVars l <> freeVars r
 freeVars (SLambda v b  ) = foldr Set.delete (freeVars b) v
-freeVars  _              = Set.empty
+freeVars _               = Set.empty

 reorderDefs :: Env -> [TricuAST] -> [TricuAST]
 reorderDefs env defs
@ -144,23 +143,18 @@ reorderDefs env defs

 buildDepGraph :: [TricuAST] -> Map.Map String (Set.Set String)
 buildDepGraph topDefs
-  | not (null conflictingDefs) =
+  | not (null duplicateNames) =
      errorWithoutStackTrace $
-        "Conflicting definitions detected: " ++ show conflictingDefs
+        "Duplicate definitions detected: " ++ show duplicateNames
  | otherwise =
      Map.fromList
        [ (name, depends topDefs (SDef name [] body))
        | SDef name _ body <- topDefs]
  where
-    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)
-      ]
+    names = [name | SDef name _ _ <- topDefs]
+    duplicateNames =
+      [ name | (name, count) <- Map.toList (countOccurrences names) , count > 1]
+    countOccurrences = foldr (\x -> Map.insertWith (+) x 1) Map.empty

 sortDeps :: Map.Map String (Set.Set String) -> [String]
 sortDeps graph = go [] Set.empty (Map.keys graph)
--- a/src/FileEval.hs
+++ b/src/FileEval.hs
@ -6,153 +6,145 @@ 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
  let tokens = lexTricu contents
+  let moduleName = case parseProgram tokens of
+        Right ((SModule name) : _) -> name
+        _                          -> ""
  case parseProgram tokens of
    Left err -> errorWithoutStackTrace (handleParseError err)
-    Right ast -> do
-      processedAst <- preprocessFile filePath
-      let finalEnv = evalTricu Map.empty processedAst
-      case extractMain finalEnv of
-        Right result -> return result
-        Left err -> errorWithoutStackTrace err
+    Right _ -> do
+      ast <- preprocessFile filePath
+      let finalEnv = mainAlias moduleName $ evalTricu Map.empty ast
+      case Map.lookup "main" finalEnv of
+        Just finalResult -> return finalResult
+        Nothing -> errorWithoutStackTrace "No `main` function detected"

 evaluateFile :: FilePath -> IO Env
 evaluateFile filePath = do
  contents <- readFile filePath
  let tokens = lexTricu contents
+  let moduleName = case parseProgram tokens of
+        Right ((SModule name) : _) -> name
+        _                          -> ""
  case parseProgram tokens of
    Left err -> errorWithoutStackTrace (handleParseError err)
-    Right ast -> do
+    Right _ -> do
      ast <- preprocessFile filePath
-      pure $ evalTricu Map.empty ast
+      pure $ mainAlias moduleName $ evalTricu Map.empty ast

 evaluateFileWithContext :: Env -> FilePath -> IO Env
 evaluateFileWithContext env filePath = do
  contents <- readFile filePath
  let tokens = lexTricu contents
+  let moduleName = case parseProgram tokens of
+        Right ((SModule name) : _) -> name
+        _                          -> ""
  case parseProgram tokens of
    Left err -> errorWithoutStackTrace (handleParseError err)
-    Right ast -> do
+    Right _ -> do
      ast <- preprocessFile filePath
-      pure $ evalTricu env ast
+      pure $ mainAlias moduleName $ evalTricu env ast
+
+mainAlias :: String -> Env -> Env
+mainAlias "" env = env
+mainAlias moduleName env =
+  case Map.lookup (moduleName ++ ".main") env of
+    Just value -> Map.insert "main" value env
+    Nothing    -> env

 preprocessFile :: FilePath -> IO [TricuAST]
-preprocessFile p = preprocessFile' Set.empty p p
+preprocessFile filePath = preprocessFile' Set.empty 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 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
+preprocessFile' :: Set.Set FilePath -> FilePath -> IO [TricuAST]
+preprocessFile' inProgress filePath
+  | filePath `Set.member` inProgress = 
+      errorWithoutStackTrace $ "Encountered cyclic import: " ++ filePath
+  | otherwise = do
+      contents <- readFile filePath
+      let tokens = lexTricu contents
+      case parseProgram tokens of
+        Left err -> errorWithoutStackTrace (handleParseError err)
+        Right asts -> do
+          let (moduleName, restAST) = extractModule asts
+          let (imports, nonImports) = partition isImport restAST
+          let newInProgress = Set.insert filePath inProgress
+          importedASTs <- concat <$> mapM (processImport newInProgress) imports
+          let namespacedAST = namespaceDefinitions moduleName nonImports
+          pure $ importedASTs ++ namespacedAST
  where
-    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
+    extractModule :: [TricuAST] -> (String, [TricuAST])
+    extractModule ((SModule name) : xs) = (name, xs)
+    extractModule xs                    = ("", xs)

-makeRelativeTo :: FilePath -> FilePath -> FilePath
-makeRelativeTo f i =
-    let d = takeDirectory f
-    in normalise $ d </> i
+    isImport :: TricuAST -> Bool
+    isImport (SImport _ _) = True
+    isImport _             = False

-nsDefinitions :: String -> [TricuAST] -> [TricuAST]
-nsDefinitions moduleName = map (nsDefinition moduleName)
+    processImport :: Set.Set FilePath -> TricuAST -> IO [TricuAST]
+    processImport inProgress (SImport filePath moduleName) = do
+      importedAST <- preprocessFile' inProgress filePath
+      pure $ namespaceDefinitions moduleName importedAST
+    processImport _ _ = error "Unexpected non-import in processImport"

-nsDefinition :: String -> TricuAST -> TricuAST
-nsDefinition "" def = def
-nsDefinition moduleName (SDef name args body)
-  | isPrefixed name = SDef name args (nsBody moduleName body)
-  | otherwise = SDef (nsVariable moduleName name)
-                        args (nsBody moduleName body)
-nsDefinition moduleName other =
-  nsBody moduleName other
+namespaceDefinitions :: String -> [TricuAST] -> [TricuAST]
+namespaceDefinitions moduleName = map (namespaceDefinition moduleName)

-nsBody :: String -> TricuAST -> TricuAST
-nsBody moduleName (SVar name)
+namespaceDefinition :: String -> TricuAST -> TricuAST
+namespaceDefinition "" def = def
+namespaceDefinition moduleName (SDef name args body)
+  | isPrefixed name = SDef name args (namespaceBody moduleName body)
+  | otherwise = SDef (namespaceVariable moduleName name) 
+                        args (namespaceBody moduleName body)
+namespaceDefinition moduleName other =
+  namespaceBody moduleName other
+
+namespaceBody :: String -> TricuAST -> TricuAST
+namespaceBody moduleName (SVar name)
  | isPrefixed name = SVar name
-  | otherwise = SVar (nsVariable moduleName name)
-nsBody moduleName (SApp func arg) =
-  SApp (nsBody moduleName func) (nsBody moduleName arg)
-nsBody moduleName (SLambda args body) =
-  SLambda args (nsBodyScoped moduleName args body)
-nsBody moduleName (SList items) =
-  SList (map (nsBody moduleName) items)
-nsBody moduleName (TFork left right) =
-  TFork (nsBody moduleName left) (nsBody moduleName right)
-nsBody moduleName (TStem subtree) =
-  TStem (nsBody moduleName subtree)
-nsBody moduleName (SDef name args body)
-  | isPrefixed name = SDef name args (nsBody moduleName body)
-  | otherwise = SDef (nsVariable moduleName name)
-                        args (nsBody moduleName body)
-nsBody _ other = other
+  | otherwise = SVar (namespaceVariable moduleName name)
+namespaceBody moduleName (SApp func arg) =
+  SApp (namespaceBody moduleName func) (namespaceBody moduleName arg)
+namespaceBody moduleName (SLambda args body) =
+  SLambda args (namespaceBodyScoped moduleName args body)
+namespaceBody moduleName (SList items) =
+  SList (map (namespaceBody moduleName) items)
+namespaceBody moduleName (TFork left right) =
+  TFork (namespaceBody moduleName left) (namespaceBody moduleName right)
+namespaceBody moduleName (TStem subtree) =
+  TStem (namespaceBody moduleName subtree)
+namespaceBody moduleName (SDef name args body)
+  | isPrefixed name = SDef name args (namespaceBody moduleName body)
+  | otherwise = SDef (namespaceVariable moduleName name) 
+                        args (namespaceBody moduleName body)
+namespaceBody _ other = other

-nsBodyScoped :: String -> [String] -> TricuAST -> TricuAST
-nsBodyScoped moduleName args body = case body of
+namespaceBodyScoped :: String -> [String] -> TricuAST -> TricuAST
+namespaceBodyScoped moduleName args body = case body of
  SVar name ->
    if name `elem` args
      then SVar name
-      else nsBody moduleName (SVar name)
-  SApp func arg ->
-    SApp (nsBodyScoped moduleName args func) (nsBodyScoped moduleName args arg)
-  SLambda innerArgs innerBody ->
-    SLambda innerArgs (nsBodyScoped moduleName (args ++ innerArgs) innerBody)
-  SList items ->
-    SList (map (nsBodyScoped moduleName args) items)
-  TFork left right ->
-    TFork (nsBodyScoped moduleName args left)
-          (nsBodyScoped moduleName args right)
-  TStem subtree ->
-    TStem (nsBodyScoped moduleName args subtree)
+      else namespaceBody moduleName (SVar name)
+  SApp func arg -> SApp (namespaceBodyScoped moduleName args func) (namespaceBodyScoped moduleName args arg)
+  SLambda innerArgs innerBody -> SLambda innerArgs (namespaceBodyScoped moduleName (args ++ innerArgs) innerBody)
+  SList items -> SList (map (namespaceBodyScoped moduleName args) items)
+  TFork left right -> TFork (namespaceBodyScoped moduleName args left) (namespaceBodyScoped moduleName args right)
+  TStem subtree -> TStem (namespaceBodyScoped moduleName args subtree)
  SDef name innerArgs innerBody ->
-    SDef (nsVariable moduleName name) innerArgs
-         (nsBodyScoped moduleName (args ++ innerArgs) innerBody)
+    SDef (namespaceVariable moduleName name) innerArgs (namespaceBodyScoped moduleName (args ++ innerArgs) innerBody)
  other -> other

 isPrefixed :: String -> Bool
 isPrefixed name = '.' `elem` name

-nsVariable :: String -> String -> String
-nsVariable "" name = name
-nsVariable moduleName name = moduleName ++ "." ++ name
+namespaceVariable :: String -> String -> String
+namespaceVariable "" name = name
+namespaceVariable moduleName name = moduleName ++ "." ++ name
--- a/src/Lexer.hs
+++ b/src/Lexer.hs
@ -3,7 +3,6 @@ module Lexer where
 import Research

 import Control.Monad               (void)
-import Data.Functor                (($>))
 import Data.Void
 import Text.Megaparsec
 import Text.Megaparsec.Char hiding (space)
@ -13,12 +12,86 @@ import qualified Data.Set as Set

 type Lexer = Parsec Void String

+keywordT :: Lexer LToken
+keywordT = string "t" *> notFollowedBy alphaNumChar *> pure LKeywordT
+
+identifier :: Lexer LToken
+identifier = do
+  first <- letterChar <|> char '_'
+  rest  <- many $ letterChar 
+              <|> digitChar 
+              <|> char '_' <|> char '-' <|> char '?' <|> char '.'
+              <|> char '$' <|> char '#' <|> char '@' <|> char '%'
+  let name = first : rest
+  if (name == "t" || name == "!result")
+    then fail "Keywords (`t`, `!result`) cannot be used as an identifier"
+    else return (LIdentifier name)
+
+integerLiteral :: Lexer LToken
+integerLiteral = do
+  num <- some digitChar
+  return (LIntegerLiteral (read num))
+
+stringLiteral :: Lexer LToken
+stringLiteral = do
+  char '"'
+  content <- many (noneOf ['"'])
+  char '"' --"
+  return (LStringLiteral content)
+
+lModule :: Lexer LToken
+lModule = do
+  _ <- string "!module"
+  space1
+  LIdentifier moduleName <- identifier
+  return (LModule moduleName)
+
+lImport :: Lexer LToken
+lImport = do
+  _ <- string "!import"
+  space1
+  LStringLiteral path <- stringLiteral
+  space1
+  LIdentifier name <- identifier
+  return (LImport path name)
+
+assign :: Lexer LToken
+assign = char '=' *> pure LAssign
+
+colon :: Lexer LToken
+colon = char ':' *> pure LColon
+
+backslash :: Lexer LToken
+backslash = char '\\' *> pure LBackslash
+
+openParen :: Lexer LToken
+openParen = char '(' *> pure LOpenParen
+
+closeParen :: Lexer LToken
+closeParen = char ')' *> pure LCloseParen
+
+openBracket :: Lexer LToken
+openBracket = char '[' *> pure LOpenBracket
+
+closeBracket :: Lexer LToken
+closeBracket = char ']' *> pure LCloseBracket
+
+lnewline :: Lexer LToken
+lnewline = char '\n' *> pure LNewline
+
+sc :: Lexer ()
+sc = space
+  (void $ takeWhile1P (Just "space") (\c -> c == ' ' || c == '\t'))
+  (skipLineComment "--")
+  (skipBlockComment "|-" "-|")
+
 tricuLexer :: Lexer [LToken]
 tricuLexer = do
  sc
  header <- many $ do
    tok <- choice
-      [ try lImport
+      [ try lModule
+      , try lImport
      , lnewline
      ]
    sc
@ -33,14 +106,13 @@ tricuLexer = do
  where
    tricuLexer' =
      [ try lnewline
-      , try namespace
-      , try dot
      , try identifier
      , try keywordT
      , try integerLiteral
      , try stringLiteral
      , assign
      , colon
+      , backslash
      , openParen
      , closeParen
      , openBracket
@ -51,93 +123,3 @@ lexTricu :: String -> [LToken]
 lexTricu input = case runParser tricuLexer "" input of
  Left err -> errorWithoutStackTrace $ "Lexical error:\n" ++ errorBundlePretty err
  Right tokens -> tokens
-
-
-keywordT :: Lexer LToken
-keywordT = string "t" *> notFollowedBy alphaNumChar $> LKeywordT
-
-identifier :: Lexer LToken
-identifier = do
-  first <- lowerChar <|> char '_'
-  rest  <- many $ letterChar
-              <|> digitChar <|> char '_' <|> char '-' <|> char '?'
-              <|> char '$'  <|> char '#' <|> char '@' <|> char '%'
-  let name = first : rest
-  if name == "t" || name == "!result"
-    then fail "Keywords (`t`, `!result`) cannot be used as an identifier"
-    else return (LIdentifier name)
-
-namespace :: Lexer LToken
-namespace = do
-  name <- try (string "!Local") <|> do
-    first <- upperChar
-    rest <- many (letterChar <|> digitChar)
-    return (first:rest)
-  return (LNamespace name)
-
-dot :: Lexer LToken
-dot = char '.' $> LDot
-
-lImport :: Lexer LToken
-lImport = do
-  _ <- string "!import"
-  space1
-  LStringLiteral path <- stringLiteral
-  space1
-  LNamespace name <- namespace
-  return (LImport path name)
-
-assign :: Lexer LToken
-assign = char '=' $> LAssign
-
-colon :: Lexer LToken
-colon = char ':' $> LColon
-
-openParen :: Lexer LToken
-openParen = char '(' $> LOpenParen
-
-closeParen :: Lexer LToken
-closeParen = char ')' $> LCloseParen
-
-openBracket :: Lexer LToken
-openBracket = char '[' $> LOpenBracket
-
-closeBracket :: Lexer LToken
-closeBracket = char ']' $> LCloseBracket
-
-lnewline :: Lexer LToken
-lnewline = char '\n' $> LNewline
-
-sc :: Lexer ()
-sc = space
-  (void $ takeWhile1P (Just "space") (\c -> c == ' ' || c == '\t'))
-  (skipLineComment "--")
-  (skipBlockComment "|-" "-|")
-
-integerLiteral :: Lexer LToken
-integerLiteral = do
-  num <- some digitChar
-  return (LIntegerLiteral (read num))
-
-stringLiteral :: Lexer LToken
-stringLiteral = do
-  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'
-        '\\' -> '\\'
-        '"'  -> '"'
-        '\'' -> '\''
--- a/src/Main.hs
+++ b/src/Main.hs
@ -8,9 +8,7 @@ import Research

 import Control.Monad          (foldM)
 import Control.Monad.IO.Class (liftIO)
-import Data.Version           (showVersion)
 import Text.Megaparsec        (runParser)
-import Paths_tricu            (version)
 import System.Console.CmdArgs

 import qualified Data.Map as Map
@ -54,16 +52,14 @@ decodeMode = TDecode

 main :: IO ()
 main = do
-  let versionStr = "tricu Evaluator and REPL " ++ showVersion version
  args <- cmdArgs $ modes [replMode, evaluateMode, decodeMode]
    &= help "tricu: Exploring Tree Calculus"
    &= program "tricu"
-    &= summary versionStr
-    &= versionArg [explicit, name "version", summary versionStr]
+    &= 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.`"
+      putStrLn "You can exit with `CTRL+D` or the `:_exit` command.`"
      repl Map.empty
    Evaluate { file = filePaths, form = form } -> do
      result <- case filePaths of
--- a/src/Parser.hs
+++ b/src/Parser.hs
@ -3,12 +3,12 @@ module Parser where
 import Lexer
 import Research

-import Control.Monad             (void)
+import Control.Monad (void)
 import Control.Monad.State
-import Data.List.NonEmpty        (toList)
-import Data.Void                 (Void)
+import Data.List.NonEmpty (toList)
+import Data.Void (Void)
 import Text.Megaparsec
-import Text.Megaparsec.Error     (ParseErrorBundle, errorBundlePretty)
+import Text.Megaparsec.Error (ParseErrorBundle, errorBundlePretty)
 import qualified Data.Set as Set

 data PState = PState
@ -73,6 +73,8 @@ parseSingle input =

 parseProgramM :: ParserM [TricuAST]
 parseProgramM = do
+  skipMany topLevelNewline
+  moduleNode <- optional parseModuleM
  skipMany topLevelNewline
  importNodes <- many (do
    node <- parseImportM
@ -81,7 +83,16 @@ parseProgramM = do
  skipMany topLevelNewline
  exprs <- sepEndBy parseOneExpression (some topLevelNewline)
  skipMany topLevelNewline
-  return (importNodes ++ exprs)
+  return (maybe [] (: []) moduleNode ++ importNodes ++ exprs)
+
+
+parseModuleM :: ParserM TricuAST
+parseModuleM = do
+  LModule moduleName <- satisfyM isModule
+  pure (SModule moduleName)
+  where
+    isModule (LModule _) = True
+    isModule _           = False

 parseImportM :: ParserM TricuAST
 parseImportM = do
@ -130,6 +141,7 @@ parseFunctionM = do
 parseLambdaM :: ParserM TricuAST
 parseLambdaM = do
  let ident = (\case LIdentifier _ -> True; _ -> False)
+  _      <- satisfyM (== LBackslash)
  params <- some (satisfyM ident)
  _      <- satisfyM (== LColon)
  scnParserM
@ -144,11 +156,11 @@ parseLambdaExpressionM = choice

 parseAtomicLambdaM :: ParserM TricuAST
 parseAtomicLambdaM = choice
-  [ try parseLambdaM
-  , parseVarM
+  [ parseVarM
  , parseTreeLeafM
  , parseLiteralM
  , parseListLiteralM
+  , try parseLambdaM
  , between (satisfyM (== LOpenParen)) (satisfyM (== LCloseParen)) parseLambdaExpressionM
  ]

@ -204,8 +216,7 @@ parseTreeLeafOrParenthesizedM = choice

 parseAtomicM :: ParserM TricuAST
 parseAtomicM = choice
-  [ try parseLambdaM
-  , parseVarM
+  [ parseVarM
  , parseTreeLeafM
  , parseListLiteralM
  , parseGroupedM
@ -255,19 +266,12 @@ parseSingleItemM = do

 parseVarM :: ParserM TricuAST
 parseVarM = do
-  token <- satisfyM (\case
-    LNamespace _ -> True
-    LIdentifier _ -> True
-    _ -> False)
-  case token of
-    LNamespace ns -> do
-      _ <- satisfyM (== LDot)
-      LIdentifier name <- satisfyM (\case LIdentifier _ -> True; _ -> False)
-      pure $ SVar (ns ++ "." ++ name)
+  satisfyM (\case LIdentifier _ -> True; _ -> False) >>= \case
    LIdentifier name
      | name == "t" || name == "!result" ->
        fail ("Reserved keyword: " ++ name ++ " cannot be assigned.")
-      | otherwise -> pure (SVar name)
+      | otherwise                         ->
+         pure (SVar name)
    _ -> fail "Unexpected token while parsing variable"

 parseIntLiteralM :: ParserM TricuAST
--- a/src/REPL.hs
+++ b/src/REPL.hs
@ -6,185 +6,56 @@ import Lexer
 import Parser
 import Research

-import Control.Exception         (IOException, SomeException, catch
-                                 , displayException)
-import Control.Monad             (forM_)
-import Control.Monad.Catch       (handle, MonadCatch)
+import Control.Exception         (SomeException, catch)
 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 Data.Char                 (isSpace)
+import Data.List                 (dropWhile, dropWhileEnd, intercalate)
 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 settings (withInterrupt (loop env Decode))
+repl env = runInputT defaultSettings (loop env)
  where
-    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
+    loop :: Env -> InputT IO ()
+    loop env = do
      minput <- getInputLine "tricu < "
-      case minput of
-        Nothing -> outputStrLn "Exiting tricu"
-        Just s
-          | strip s == "" -> loop env form
-          | strip s == "!exit" -> outputStrLn "Exiting tricu"
-          | 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 form `catch` errorHandler env
-              loop newEnv form
+      if
+        | Nothing <- minput                     -> outputStrLn "Exiting tricu"
+        | Just s  <- minput, strip s == "!exit" -> outputStrLn "Exiting tricu"
+        | Just s  <- minput, strip s == ""      -> do
+          outputStrLn ""
+          loop env
+        | Just s  <- minput, strip s == "!import" -> do
+          path <- getInputLine "File path to load < "
+          if
+            | Nothing <- path -> do
+              outputStrLn "No input received; stopping import."
+              loop env
+            | Just p  <- path -> do
+              loadedEnv <- liftIO $ evaluateFileWithContext env (strip p) `catch` \e -> errorHandler env e
+              loop $ Map.delete "!result" (Map.union loadedEnv env)
+        | Just s <- minput -> do
+          if
+            | take 2 s == "--" -> loop env
+            | otherwise -> do
+              newEnv <- liftIO $ processInput env s `catch` errorHandler env
+              loop newEnv

-    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 form
-
-    processInput :: Env -> String -> EvaluatedForm -> IO Env
-    processInput env input form = do
+    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 -> do
-          putStrLn $ "tricu > " ++ formatResult form r
-        Nothing -> pure ()
+      if
+        | Just r <- Map.lookup "!result" newEnv -> do
+          putStrLn $ "tricu > " ++ decodeResult r
+        | otherwise -> 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
-
-    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
--- a/src/Research.hs
+++ b/src/Research.hs
@ -1,5 +1,6 @@
 module Research where

+import Control.Monad.State
 import Data.List                 (intercalate)
 import Data.Map                  (Map)
 import Data.Text                 (Text, replace)
@ -25,6 +26,7 @@ data TricuAST
  | TFork TricuAST TricuAST
  | SLambda [String] TricuAST
  | SEmpty
+  | SModule String
  | SImport String String
  deriving (Show, Eq, Ord)

@ -32,17 +34,17 @@ data TricuAST
 data LToken
  = LKeywordT
  | LIdentifier String
-  | LNamespace String
  | LIntegerLiteral Int
  | LStringLiteral String
  | LAssign
  | LColon
-  | LDot
+  | LBackslash
  | LOpenParen
  | LCloseParen
  | LOpenBracket
  | LCloseBracket
  | LNewline
+  | LModule String
  | LImport String String
  deriving (Show, Eq, Ord)

@ -51,26 +53,17 @@ data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii | Decode
  deriving (Show, Data, Typeable)

 -- Environment containing previously evaluated TC terms
-type Env = Map.Map String T
+type Env = Map.Map String T 

-- 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
-}
+-- Tree Calculus Reduction
 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 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
@ -84,7 +77,7 @@ _not = Fork (Fork _true (Fork Leaf _false)) Leaf

 -- Marshalling
 ofString :: String -> T
-ofString str = ofList $ map (ofNumber . fromEnum) str
+ofString str = ofList (map ofNumber (map fromEnum str))

 ofNumber :: Int -> T
 ofNumber 0 = Leaf
@ -94,7 +87,8 @@ ofNumber n =
    (ofNumber (n `div` 2))

 ofList :: [T] -> T
-ofList = foldr Fork Leaf
+ofList [] = Leaf
+ofList (x:xs) = Fork x (ofList xs)

 toNumber :: T -> Either String Int
 toNumber Leaf = Right 0
@ -128,11 +122,11 @@ formatResult Ascii        = toAscii
 formatResult Decode       = decodeResult

 toSimpleT :: String -> String
-toSimpleT s = T.unpack
+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"
@ -159,18 +153,8 @@ toAscii tree = go tree "" True
        ++ go right (prefix ++ (if isLast then "    " else "|   ")) True

 decodeResult :: T -> String
-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
+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
--- a/test/Spec.hs
+++ b/test/Spec.hs
@ -30,11 +30,10 @@ tests = testGroup "Tricu Tests"
  , parser
  , simpleEvaluation
  , lambdas
-  , providedLibraries
+  , baseLibrary
  , fileEval
  , modules
  , demos
-  , decoding
  ]

 lexer :: TestTree
@ -51,22 +50,7 @@ lexer = testGroup "Lexer Tests"

  , testCase "Lex escaped characters in strings" $ do
      let input = "\"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 "\""]
+          expect = Right [LStringLiteral "hello\\nworld"]
      runParser tricuLexer "" input @?= expect

  , testCase "Lex mixed literals" $ do
@ -102,7 +86,7 @@ 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

@ -122,7 +106,7 @@ 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

@ -164,22 +148,22 @@ 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

@ -274,7 +258,7 @@ 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
  ]
@ -282,182 +266,214 @@ 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 applied to string literal" $ do
-        let input = "f = (x : x)\nf \"hello\""
+  , 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 applied to integer literal" $ do
-        let input = "f = (x : x)\nf 42"
+   , 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 applied to list literal" $ do
-        let input = "f = (x : x)\nf [t (t t)]"
+   , testCase "Lambda with a list literal" $ do
+        let input = "f = (\\x : x)\nf [t (t t)]"
        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
-
-  , testCase "Lambda containing list literal" $ do
-      let input = "(a : [(a)]) 1"
-      runTricu input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
  ]

-providedLibraries :: TestTree
-providedLibraries = testGroup "Library Tests"
-  [ testCase "Triage test Leaf" $ do
-      library <- evaluateFile "./lib/list.tri"
+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"
      let input = "test t"
          env = decodeResult $ result $ evalTricu library (parseTricu input)
      env @?= "\"Leaf\""

  , testCase "Triage test (Stem Leaf)" $ do
-      library <- evaluateFile "./lib/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
-      let input = "head (tail (map (a : (t t t)) [(t) (t) (t)]))"
+      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/list.tri"
+      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/list.tri"
+      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/list.tri"
-      let input = "append \"Hello, \" \"world!\""
+      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/list.tri"
+      library <- evaluateFile "./lib/base.tri"
      let input = "equal? (t t t) (t t t)"
          env = evalTricu library (parseTricu input)
      result env @?= Stem Leaf
@ -474,12 +490,12 @@ fileEval = testGroup "File evaluation tests"
      res @?= Fork (Stem Leaf) Leaf

  , testCase "Mapping and Equality" $ do
-      library <- liftIO $ evaluateFile "./lib/list.tri"
+      library <- liftIO $ evaluateFile "./lib/base.tri"
      fEnv    <- liftIO $ evaluateFileWithContext library "./test/map.tri"
      (mainResult fEnv) @?= Stem Leaf

  , testCase "Eval and decoding string" $ do
-      library <- liftIO $ evaluateFile "./lib/list.tri"
+      library <- liftIO $ evaluateFile "./lib/base.tri"
      res <- liftIO $ evaluateFileWithContext library "./test/string.tri"
      decodeResult (result res) @?= "\"String test!\""
  ]
@ -516,9 +532,6 @@ modules = testGroup "Test modules"
  , testCase "Lambda expression namespaces" $ do
      res <- liftIO $ evaluateFileResult "./test/lambda-A.tri"
      res @?= Leaf
-  , testCase "Local namespace import chain" $ do
-      res <- liftIO $ evaluateFileResult "./test/local-ns/1.tri"
-      res @?=  Fork (Stem Leaf) (Fork (Stem Leaf) Leaf)
  ]


@ -538,35 +551,3 @@ 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\"]"
-  ]
--- a/test/ascii.tri
+++ b/test/ascii.tri
@ -0,0 +1 @@
+t (t (t (t (t t) (t t t)) t) t t) t
--- a/test/assignment.tri
+++ b/test/assignment.tri
@ -0,0 +1 @@
+x = t (t t) t
--- a/test/comments-1.tri
+++ b/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
--- a/test/cycle-1.tri
+++ b/test/cycle-1.tri
@ -1,4 +1,5 @@
+!module Cycle

-!import "cycle-2.tri" Cycle2
+!import "test/cycle-2.tri" Cycle2

 cycle1 = t Cycle2.cycle2
--- a/test/cycle-2.tri
+++ b/test/cycle-2.tri
@ -1,4 +1,5 @@
+!module Cycle2

-!import "cycle-1.tri" Cycle1
+!import "test/cycle-1.tri" Cycle1

 cycle2 = t Cycle1.cycle1
--- a/test/lambda-A.tri
+++ b/test/lambda-A.tri
@ -1 +1,2 @@
-main = (x : x) t
+!module A
+main = (\x : x) t
--- a/test/local-ns/1.tri
+++ b/test/local-ns/1.tri
@ -1,4 +0,0 @@
-
-!import "2.tri" Two
-
-main = Two.x
--- a/test/local-ns/2.tri
+++ b/test/local-ns/2.tri
@ -1,2 +0,0 @@
-
-!import "3.tri" !Local
--- a/test/local-ns/3.tri
+++ b/test/local-ns/3.tri
@ -1 +0,0 @@
-x = 3
--- a/test/map.tri
+++ b/test/map.tri
@ -1,2 +1,2 @@
-x = map (i : append "Successfully concatenated " i) [("two strings!")]
+x = map (\i : lconcat "Successfully concatenated " i) [("two strings!")]
 main = equal? x [("Successfully concatenated two strings!")]
--- a/test/modules-1.tri
+++ b/test/modules-1.tri
@ -0,0 +1,5 @@
+!module Test
+
+!import "lib/base.tri" Lib
+
+main = Lib.not? t
--- a/test/modules-2.tri
+++ b/test/modules-2.tri
@ -0,0 +1 @@
+n = t t t
--- a/test/multi-level-A.tri
+++ b/test/multi-level-A.tri
@ -1,2 +1,3 @@
-!import "multi-level-B.tri" B
+!module A
+!import "./test/multi-level-B.tri" B
 main = B.main
--- a/test/multi-level-B.tri
+++ b/test/multi-level-B.tri
@ -1,2 +1,3 @@
-!import "multi-level-C.tri" C
+!module B
+!import "./test/multi-level-C.tri" C
 main = C.val
--- a/test/multi-level-C.tri
+++ b/test/multi-level-C.tri
@ -1 +1,2 @@
+!module C
 val = t
--- a/test/named-imports/1.tri
+++ b/test/named-imports/1.tri
@ -1,7 +0,0 @@
-
-!import "lib/base.tri"
-
-!import "test/named-imports/2.tri"
-!import "test/named-imports/3.tri" ThreeRenamed
-
-main = equal? (equal? Two.x 2) (equal? ThreeRenamed.x 3)
--- a/test/named-imports/2.tri
+++ b/test/named-imports/2.tri
@ -1,2 +0,0 @@
-
-x = 2
--- a/test/named-imports/3.tri
+++ b/test/named-imports/3.tri
@ -1,2 +0,0 @@
-
-x = 3
--- a/test/namespace-A.tri
+++ b/test/namespace-A.tri
@ -1,2 +1,3 @@
-!import "namespace-B.tri" B
+!module A
+!import "./test/namespace-B.tri" B
 main = B.x
--- a/test/namespace-B.tri
+++ b/test/namespace-B.tri
@ -1 +1,2 @@
+!module B
 x = t
--- a/test/size.tri
+++ b/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
--- a/test/string.tri
+++ b/test/string.tri
@ -1 +1 @@
-head (map (i : append "String " i) [("test!")])
+head (map (\i : lconcat "String " i) [("test!")])
--- a/test/undefined.tri
+++ b/test/undefined.tri
@ -0,0 +1 @@
+namedTerm = undefinedForTesting
--- a/test/unresolved-A.tri
+++ b/test/unresolved-A.tri
@ -1 +1,2 @@
+!module A
 main = undefinedVar
--- a/test/vars-A.tri
+++ b/test/vars-A.tri
@ -1,6 +1,7 @@
+!module A

-!import "vars-B.tri" B
+!import "./test/vars-B.tri" B

-!import "vars-C.tri" C
+!import "./test/vars-C.tri" C

 main = B.y (C.z)
--- a/test/vars-B.tri
+++ b/test/vars-B.tri
@ -1 +1,2 @@
-y = x : x
+!module B
+y = \x : x
--- a/test/vars-C.tri
+++ b/test/vars-C.tri
@ -1 +1,2 @@
+!module C
 z = t
--- a/tricu.cabal
+++ b/tricu.cabal
@ -1,7 +1,7 @@
 cabal-version: 1.12

 name:           tricu
-version:        0.18.1
+version:        0.12.0
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co
@ -26,13 +26,10 @@ executable tricu
    base >=4.7
    , cmdargs
    , containers
-    , exceptions
-    , filepath
    , haskeline
    , megaparsec
    , mtl
    , text
-    , transformers
  other-modules:
    Eval
    FileEval
@ -55,8 +52,6 @@ test-suite tricu-tests
    base
    , cmdargs
    , containers
-    , exceptions
-    , filepath
    , haskeline
    , megaparsec
    , mtl
@ -64,7 +59,6 @@ test-suite tricu-tests
    , tasty-hunit
    , tasty-quickcheck
    , text
-    , transformers
  default-language:    Haskell2010
  other-modules:
    Eval