.gitea/workflows/test-and-build.yml

@@ -28,16 +28,6 @@ jobs:
           restore-keys: |
             cabal-
 
-      - name: Set up cache for Nix
-        uses: actions/cache@v4
-        with:
-          path: |
-            /nix/store
-            /nix/var/nix/cache
-          key: nix-${{ hashFiles('flake.lock') }}
-          restore-keys: |
-            nix-
-
       - name: Initialize Cabal and update package list
         run: |
           nix develop --command cabal update
@@ -58,29 +48,18 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up cache for Nix
+      - name: Build and shrink binary
-        uses: actions/cache@v4
-        with:
-          path: |
-            /nix/store
-            /nix/var/nix/cache
-          key: nix-${{ hashFiles('flake.lock') }}
-          restore-keys: |
-            nix-
-  
-      - name: Build binary
         run: |
           nix build
-          ls -alh ./result/bin/tricu
+          cp -L ./result/bin/tricu ./tricu
-  
+          chmod 755 ./tricu
-      - name: Setup go for release actoin
+          nix develop --command upx ./tricu
-        uses: actions/setup-go@v5
-        with:
-          go-version: '>=1.20.1'
 
       - name: Release binary
-        uses: https://gitea.com/actions/release-action@main
+        uses: akkuman/gitea-release-action@v1
         with:
           files: |-
-            ./result/bin/tricu
+            ./tricu
-          api_key: '${{ secrets.RELEASE_TOKEN }}'
+          token: '${{ secrets.RELEASE_TOKEN }}'
+          body: '${{ gitea.event.head_commit.message }}'
+          prerelease: true

.gitignore

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

README.md

@@ -2,43 +2,60 @@
 
 ## Introduction
 
-tricu (pronounced "tree-shoe") 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).
+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 offers minimal syntax sugar yet manages to provide a complete, intuitive, and familiar programming environment. There is great power in simplicity. tricu offers:
+*tricu is under active development and you should expect breaking changes with every commit.*
 
-1. `t` operator behaving by the rules of Tree Calculus
+tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`.
-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.
+## Features
 
-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.
+- Tree Calculus operator: `t`
+- 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")]`
+- Intensionality blurs the distinction between functions and data (see REPL examples)
+- Simple module system for code organization
 
-## What does it look like?
+## REPL examples
 
 ```
 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 < head (map (\i : append i " world!") [("Hello, ")])
 tricu > "Hello,  world!"
-tricu < id (head (map (\i : lconcat i " world!") [("Hello, ")]))
+tricu < id (head (map (\i : append i " world!") [("Hello, ")]))
 tricu > "Hello,  world!"
 
-tricu < -- Intensionality! We can inspect the structure of a function.
+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 < test (t t)
 tricu > "Stem"
-tricu < -- We can even write a function to convert a term back to source code
+tricu < -- We can even convert a term back to source code (/demos/toSource.tri)
 tricu < toSource not?
 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/or run this project using [Nix](https://nixos.org/download/).
+You can easily build and run this project using [Nix](https://nixos.org/download/).
 
 - Quick Start (REPL): 
   - `nix run git+https://git.eversole.co/James/tricu`
@@ -65,7 +82,7 @@ tricu eval [OPTIONS]
 
   -f --file=FILE  Input file path(s) for evaluation.
                     Defaults to stdin.
-  -t --form=FORM  Optional output form: (tree|fsl|ast|ternary|ascii).
+  -t --form=FORM  Optional output form: (tree|fsl|ast|ternary|ascii|decode).
                     Defaults to tricu-compatible `t` tree form.
 
 tricu decode [OPTIONS]
@@ -75,8 +92,14 @@ 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). 
 
-[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.
+[treecalcul.us](https://treecalcul.us) is an excellent website with an intuitive Tree Calculus code playground created by [Johannes Bader](https://johannes-bader.com/) that introduced me to Tree Calculus.

demos/equality.tri

@@ -1,24 +1,40 @@
-false = t
+!import "../lib/base.tri" !Local
-true  = t t
+!import "../lib/list.tri" !Local
 
-triage = (\a b c : t (t a b) c)
+main = lambdaEqualsTC
 
-matchBool = (\ot of : triage
+-- We represent `false` with a Leaf and `true` with a Stem Leaf
+demo_false = t
+demo_true  = t t
+
+-- Tree Calculus representation of the Boolean `not` function
+not_TC?     = t (t (t t) (t t t)) (t t (t t t))
+
+-- /demos/toSource.tri contains an explanation of `triage`
+demo_triage = \a b c : t (t a b) c
+demo_matchBool = (\ot of : demo_triage
   of
   (\_ : ot)
   (\_ _ : ot)
 )
+-- Lambda representation of the Boolean `not` function
+not_Lambda? = demo_matchBool demo_false demo_true
 
-not_TC?     = t (t (t t) (t t t)) (t t (t t t))
+-- Since tricu eliminates Lambda terms to SKI combinators, the tree form of many
-not_Lambda? = matchBool false true
+-- functions defined via Lambda terms are larger than the most efficient TC
+-- representation. Between different languages that evaluate to tree calculus 
+-- terms, the exact implementation of Lambda elimination may differ and lead 
+-- to different tree representations even if they share extensional behavior.
 
-areEqual? = equal not_TC not_Lambda
+-- Let's see if these are the same:
+lambdaEqualsTC = equal? not_TC? not_Lambda?
 
-true_TC?  = not_TC false
+-- Here are some checks to verify their extensional behavior is the same:
-false_TC? = not_TC true
+true_TC?  = not_TC? demo_false
+false_TC? = not_TC? demo_true
 
-true_Lambda?  = not_Lambda false
+true_Lambda?  = not_Lambda? demo_false
-false_Lambda? = not_Lambda true
+false_Lambda? = not_Lambda? demo_true
 
-areTrueEqual?  = equal true_TC  true_Lambda
+bothTrueEqual?  = equal? true_TC?  true_Lambda?
-areFalseEqual? = equal false_TC false_Lambda
+bothFalseEqual? = equal? false_TC? false_Lambda?

demos/levelOrderTraversal.tri

@@ -1,11 +1,13 @@
+!import "../lib/base.tri" Lib
+!import "../lib/list.tri" !Local
+
+main = exampleTwo
 -- 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 nested lists where values act as labels. We
--- 
--- 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`. 
+-- with an empty list, `[]`, which evaluates to a single node `t`.
 --
 -- Example tree inputs:
 -- [("1") [("2") [("4") t t] t] [("3") [("5") t t] [("6") t t]]]]
@@ -15,43 +17,42 @@
 --     2   3
 --    /   /  \
 --   4   5    6
---
 
-label = (\node : head node)
+label = \node : head node
 
-left  = (\node : if (emptyList node) 
+left = (\node : if (emptyList? node)
   [] 
-  (if (emptyList (tail node)) 
+  (if (emptyList? (tail node)) 
     [] 
     (head (tail node))))
 
-right = (\node : if (emptyList node) 
+right = (\node : if (emptyList? node) 
   [] 
-  (if (emptyList (tail node)) 
+  (if (emptyList? (tail node)) 
     [] 
-    (if (emptyList (tail (tail node))) 
+    (if (emptyList? (tail (tail node))) 
       [] 
       (head (tail (tail node))))))
 
-processLevel = y (\self queue : if (emptyList queue) 
+processLevel = y (\self queue : if (emptyList? queue) 
   [] 
   (pair (map label queue) (self (filter 
-    (\node : not (emptyList node)) 
+    (\node : not? (emptyList? node)) 
-      (lconcat (map left queue) (map right queue))))))
+      (append (map left queue) (map right queue))))))
 
-levelOrderTraversal_ = (\a : processLevel (t a t))
+levelOrderTraversal_ = \a : processLevel (t a t)
 
-toLineString = y (\self levels : if (emptyList levels) 
+toLineString = y (\self levels : if (emptyList? levels) 
   "" 
-  (lconcat 
+  (append 
-    (lconcat (map (\x : lconcat x " ") (head levels)) "") 
+    (append (map (\x : append x " ") (head levels)) "") 
-    (if (emptyList (tail levels)) "" (lconcat (t (t 10 t) t) (self (tail levels))))))
+    (if (emptyList? (tail levels)) "" (append (t (t 10 t) t) (self (tail levels))))))
 
-levelOrderToString = (\s : toLineString (levelOrderTraversal_ s))
+levelOrderToString = \s : toLineString (levelOrderTraversal_ s)
 
-flatten = foldl (\acc x : lconcat acc x) ""
+flatten = foldl (\acc x : append acc x) ""
 
-levelOrderTraversal = (\s : lconcat (t 10 t) (flatten (levelOrderToString s)))
+levelOrderTraversal = \s : append (t 10 t) (flatten (levelOrderToString s))
 
 exampleOne = levelOrderTraversal [("1") 
                                  [("2") [("4") t t] t] 
@@ -61,5 +62,3 @@ 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]]]
-
-exampleTwo

demos/size.tri

@@ -0,0 +1,13 @@
+!import "../lib/base.tri" !Local
+!import "../lib/list.tri" !Local
+
+main = size size
+
+size = (\x :
+  (y (\self x :
+    compose succ
+      (triage
+        (\x : x)
+        self
+        (\x y : compose (self x) (self y))
+        x)) x 0))

demos/toSource.tri

@@ -1,14 +1,18 @@
+!import "../lib/base.tri" !Local
+!import "../lib/list.tri" !Local
+
+main = toSource not?
 -- Thanks to intensionality, we can inspect the structure of a given value
 -- even if it's a function. This includes lambdas which are eliminated to
 -- Tree Calculus (TC) terms during evaluation.
 
--- Triage takes four arguments: the first three represent behaviors for each 
+-- `triage` takes four arguments: the first three represent behaviors for each 
 -- structural case in Tree Calculus (Leaf, Stem, and Fork).
 -- The fourth argument is the value whose structure is inspected. By evaluating 
 -- the Tree Calculus term, `triage` enables branching logic based on the term's 
 -- shape, making it possible to perform structure-specific operations such as
 -- reconstructing the terms' source code representation.
-triage = (\a b c : t (t a b) c)
+-- triage = (\leaf stem fork : t (t leaf stem) fork)
 
 -- Base case of a single Leaf
 sourceLeaf = t (head "t")
@@ -34,13 +38,13 @@ sourceFork = (\convert : (\a b rest :
 -- Wrapper around triage 
 toSource_ = y (\self arg :
   triage
-    sourceLeaf        -- Triage `a` case, Leaf
+    sourceLeaf        -- `triage` "a" case, Leaf
-    (sourceStem self) -- Triage `b` case, Stem
+    (sourceStem self) -- `triage` "b" case, Stem
-    (sourceFork self) -- Triage `c` case, Fork
+    (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)))"
+exampleTwo = toSource not? -- OUT: "(t (t (t t) (t t t)) (t t (t t t)))"

flake.nix

@@ -32,10 +32,12 @@
         defaultPackage = self.packages.${system}.default;
 
         devShells.default = pkgs.mkShell {
-          buildInputs = with pkgs.haskellPackages; [
+          buildInputs = with pkgs; [
-            cabal-install
+            haskellPackages.cabal-install
-            ghcid
+            haskellPackages.ghc-events
+            haskellPackages.ghcid
             customGHC
+            upx
           ];
           inputsFrom = builtins.attrValues self.packages.${system};
         };

lib/base.tri

@@ -1,24 +1,18 @@
 false = t
 _     = t
 true  = t t
-k     = t t
+id    = \a : a
-i     = t (t k) t
+const = \a b : a
-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)
 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
 
-triage = (\a b c : t (t a b) c)
+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")
 
 matchBool = (\ot of : triage
@@ -27,46 +21,32 @@ matchBool = (\ot of : triage
   (\_ _ : ot)
 )
 
-matchList = (\oe oc : triage 
-  oe 
-  _ 
-  oc
-)
-
-matchPair = (\op : triage 
-  _ 
-  _ 
-  op
-)
-
-not? = matchBool false true
-and? = matchBool id (\_ : false)
-emptyList? = matchList true (\_ _ : false)
-
-head = matchList t (\head _ : head)
-tail = matchList t (\_ tail : tail)
-
-lconcat = y (\self : matchList 
-  (\k : k) 
-  (\h r k : pair h (self r k)))
-
 lAnd = (triage
   (\_     : false)
   (\_ x   : x)
-  (\_ _ x : x)
+  (\_ _ x : x))
-)
 
 lOr = (triage
   (\x     : x)
   (\_ _   : true)
-  (\_ _ _ : true)
+  (\_ _ _ : true))
-)
 
-map_ = y (\self : 
+matchPair = \a : triage _ _ a
-  matchList 
+
-    (\_ : t) 
+not? = matchBool false true
-    (\head tail f : pair (f head) (self tail f)))
+and? = matchBool id (\_ : false)
-map = (\f l : map_ l f)
+
+or? = (\x z : 
+  matchBool 
+    (matchBool true true z)
+    (matchBool true false z)
+    x)
+
+xor? = (\x z : 
+  matchBool 
+    (matchBool false true z)
+    (matchBool true false z)
+    x)
 
 equal? = y (\self : triage
   (triage
@@ -84,13 +64,11 @@ equal? = y (\self : triage
       (\_ : false)
       (\bx by : lAnd (self ax bx) (self ay by))))
 
-filter_ = y (\self : matchList 
+succ = y (\self :
-  (\_ : t) 
+  triage
-  (\head tail f : matchBool (t head) i (f head) (self tail f)))
+    1
-filter  = (\f l : filter_ l f)
+    t
-
+    (triage
-foldl_ = y (\self f l x : matchList (\acc : acc) (\head tail acc : self f tail (f acc head)) l x)
+      (t (t t))
-foldl  = (\f x l : foldl_ f l x)
+      (\_ tail : t t (self tail))
-
+      t))
-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)

lib/list.tri

@@ -0,0 +1,68 @@
+!import "base.tri" !Local
+
+matchList = \a b : triage a _ b
+
+emptyList? = matchList true (\_ _ : false)
+head = matchList t (\head _ : head)
+tail = matchList t (\_ tail : tail)
+
+append = y (\self : matchList
+  (\k : k)
+  (\h r k : pair h (self r k)))
+
+lExist? = y (\self x : matchList
+  false
+  (\h z : or? (equal? x h) (self x z)))
+
+map_ = y (\self :
+  matchList
+    (\_ : t)
+    (\head tail f : pair (f head) (self tail f)))
+map = \f l : map_ l f
+
+filter_ = y (\self : matchList
+  (\_ : t)
+  (\head tail f : matchBool (t head) id (f head) (self tail f)))
+filter  = \f l : filter_ l f
+
+foldl_ = y (\self f l x : matchList (\acc : acc) (\head tail acc : self f tail (f acc head)) l x)
+foldl  = \f x l : foldl_ f l x
+
+foldr_ = y (\self x f l : matchList x (\head tail : f (self x f tail) head) l)
+foldr  = \f x l : foldr_ x f l
+
+length = y (\self : matchList
+  0
+  (\_ tail : succ (self tail)))
+
+reverse = y (\self : matchList
+  t
+  (\head tail : append (self tail) (pair head t)))
+
+snoc = y (\self x : matchList
+  (pair x t)
+  (\h z : pair h (self x z)))
+
+count = y (\self x : matchList
+  0
+  (\h z : matchBool
+    (succ (self x z))
+    (self x z)
+    (equal? x h)))
+
+last = y (\self : matchList
+  t
+  (\hd tl : matchBool
+    hd
+    (self tl)
+    (emptyList? tl)))
+
+all? = y (\self pred : matchList
+  true
+  (\h z : and? (pred h) (self pred z)))
+
+any? = y (\self pred : matchList
+  false
+  (\h z : or? (pred h) (self pred z)))
+
+intersect = \xs ys : filter (\x : lExist? x ys) xs

lib/patterns.tri

@@ -0,0 +1,36 @@
+!import "list.tri" !Local
+
+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 (map (\sublist :
+    pair (head sublist) (head (tail sublist)))
+    patterns))
+
+otherwise = const (t t)
+
+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!")]])

src/Eval.hs

@@ -3,33 +3,43 @@ module Eval where
 import Parser
 import Research
 
+import Data.List (partition, (\\))
 import Data.Map  (Map)
-
 import qualified Data.Map as Map
 import qualified Data.Set as Set
 
 evalSingle :: Env -> TricuAST -> Env
 evalSingle env term
-  | SFunc name [] body <- term =
+  | SDef name [] body <- term
-      let res = evalAST env body
+  = case Map.lookup name env of
-      in Map.insert "__result" res (Map.insert name res env)
+      Just existingValue
-  | SApp func arg <- term =
+        | existingValue == evalAST env body -> env
-      let res = apply (evalAST env func) (evalAST env arg)
+        | otherwise -> errorWithoutStackTrace $
-      in Map.insert "__result" res env
+            "Unable to rebind immutable identifier: " ++ name
-  | SVar name <- term =
+      Nothing ->
-      case Map.lookup name env of
+        let res = evalAST env body
-        Just v  -> Map.insert "__result" v env
+        in Map.insert "!result" res (Map.insert name res env)
-        Nothing -> errorWithoutStackTrace $ "Variable " ++ name ++ " not defined"
+  | SApp func arg <- term
-  | otherwise =
+  = let res = apply (evalAST env func) (evalAST env arg)
-      Map.insert "__result" (evalAST env term) env
+      in Map.insert "!result" res env
+  | 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
+  = Map.insert "!result" (evalAST env term) env
 
 evalTricu :: Env -> [TricuAST] -> Env
-evalTricu env []     = env
+evalTricu env x = go env (reorderDefs env x)
-evalTricu env [x]    =
+  where
-  let updatedEnv = evalSingle env x
+    go env []     = env
-  in Map.insert "__result" (result updatedEnv) updatedEnv
+    go env [x]    =
-evalTricu env (x:xs) =
+      let updatedEnv = evalSingle env x
-  evalTricu (evalSingle env x) xs
+      in Map.insert "!result" (result updatedEnv) updatedEnv
+    go env (x:xs) =
+      evalTricu (evalSingle env x) xs
 
 evalAST :: Env -> TricuAST -> T
 evalAST env term
@@ -49,16 +59,30 @@ evalAST env term
         (errorWithoutStackTrace $ "Variable " ++ name ++ " not defined")
         name env
 
--- https://github.com/barry-jay-personal/typed_tree_calculus/blob/main/typed_program_analysis.pdf
--- Chapter 4: Lambda-Abstraction
 elimLambda :: TricuAST -> TricuAST
 elimLambda = go
   where
+    -- η-reduction
+    go (SLambda [v] (SApp f (SVar x)))
+      | v == x && not (isFree v f) = elimLambda f
+    -- Triage optimization
+    go (SLambda [a] (SLambda [b] (SLambda [c] body)))
+      | body == triageBody         = _TRIAGE
+      where
+        triageBody =
+          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
+    -- 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)
+      | null vs                    = toSKI v (elimLambda body)
-      | otherwise            = elimLambda (SLambda [v] (SLambda vs body))
+      | otherwise                  = elimLambda (SLambda [v] (SLambda vs body))
-    go (SApp f g)            = SApp (elimLambda f) (elimLambda g)
+    go (SApp f g)                  = SApp (elimLambda f) (elimLambda g)
-    go x                     = x
+    go x                           = x
 
     toSKI x (SVar y)
       | x == y           = _I
@@ -68,25 +92,106 @@ elimLambda = go
       | otherwise        = SApp (SApp _S (toSKI x n)) (toSKI x u)
     toSKI x t
       | not (isFree x t) = SApp _K t
-      | otherwise        = SApp (SApp _S (toSKI x t)) TLeaf
+      | otherwise        = errorWithoutStackTrace "Unhandled toSKI conversion"
 
-    _S = parseSingle "t (t (t t t)) t"
+    _S       = parseSingle "t (t (t t t)) t"
-    _K = parseSingle "t t"
+    _K       = parseSingle "t t"
-    _I = parseSingle "t (t (t 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"
 
-    isFree x = Set.member x . freeVars
+isFree :: String -> TricuAST -> Bool
-    freeVars (SVar    v    ) = Set.singleton v
+isFree x = Set.member x . freeVars
-    freeVars (SInt    _    ) = Set.empty
+
-    freeVars (SStr    _    ) = Set.empty
+freeVars :: TricuAST -> Set.Set String
-    freeVars (SList   s    ) = foldMap freeVars s
+freeVars (SVar    v    ) = Set.singleton v
-    freeVars (SApp    f a  ) = freeVars f <> freeVars a
+freeVars (SInt    _    ) = Set.empty
-    freeVars (TLeaf        ) = Set.empty
+freeVars (SStr    _    ) = Set.empty
-    freeVars (SFunc   _ _ b) = freeVars b
+freeVars (SList   s    ) = foldMap freeVars s
-    freeVars (TStem   t    ) = freeVars t
+freeVars (SApp    f a  ) = freeVars f <> freeVars a
-    freeVars (TFork   l r  ) = freeVars l <> freeVars r
+freeVars  TLeaf          = Set.empty
-    freeVars (SLambda v b  ) = foldr Set.delete (freeVars b) v
+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
+
+reorderDefs :: Env -> [TricuAST] -> [TricuAST]
+reorderDefs env defs
+  | not (null missingDeps) =
+      errorWithoutStackTrace $
+        "Missing dependencies detected: " ++ show missingDeps
+  | otherwise = orderedDefs ++ others
+  where
+    (defsOnly, others) = partition isDef defs
+    defNames = [ name | SDef name _ _ <- defsOnly ]
+
+    defsWithFreeVars = [(def, freeVars body) | def@(SDef _ _ body) <- defsOnly]
+
+    graph = buildDepGraph defsOnly
+    sortedDefs = sortDeps graph
+    defMap = Map.fromList [(name, def) | def@(SDef name _ _) <- defsOnly]
+    orderedDefs = map (\name -> defMap Map.! name) sortedDefs
+
+    freeVarsDefs = foldMap snd defsWithFreeVars
+    freeVarsOthers = foldMap freeVars others
+    allFreeVars = freeVarsDefs <> freeVarsOthers
+    validNames = Set.fromList defNames `Set.union` Set.fromList (Map.keys env)
+    missingDeps = Set.toList (allFreeVars `Set.difference` validNames)
+
+    isDef (SDef _ _ _) = True
+    isDef _            = False
+
+buildDepGraph :: [TricuAST] -> Map.Map String (Set.Set String)
+buildDepGraph topDefs
+  | not (null conflictingDefs) =
+      errorWithoutStackTrace $
+        "Conflicting definitions detected: " ++ show conflictingDefs
+  | 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)
+      ]
+
+sortDeps :: Map.Map String (Set.Set String) -> [String]
+sortDeps graph = go [] Set.empty (Map.keys graph)
+  where
+    go sorted sortedSet [] = sorted
+    go sorted sortedSet remaining =
+      let ready = [ name | name <- remaining
+                        , let deps = Map.findWithDefault Set.empty name graph
+                        , Set.isSubsetOf deps sortedSet ]
+          notReady = remaining \\ ready
+      in if null ready
+         then errorWithoutStackTrace
+          "ERROR: Cyclic dependency detected and prohibited.\n\
+          \RESOLVE: Use nested lambdas."
+         else go (sorted ++ ready)
+                 (Set.union sortedSet (Set.fromList ready))
+                 notReady
+
+depends :: [TricuAST] -> TricuAST -> Set.Set String
+depends topDefs (SDef _ _ body) =
+  Set.intersection
+    (Set.fromList [n | SDef n _ _ <- topDefs])
+    (freeVars body)
+depends _ _ = Set.empty
 
 result :: Env -> T
-result r = case Map.lookup "__result" r of
+result r = case Map.lookup "!result" r of
   Just a -> a
-  Nothing -> errorWithoutStackTrace "No __result field found in provided environment"
+  Nothing -> errorWithoutStackTrace "No !result field found in provided env"
+
+mainResult :: Env -> T
+mainResult r = case Map.lookup "main" r of
+  Just  a -> a
+  Nothing -> errorWithoutStackTrace "No valid definition for `main` found."

src/FileEval.hs

@@ -1,30 +1,158 @@
 module FileEval where
 
 import Eval
+import Lexer
 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 asts = parseTricu contents
+  let tokens = lexTricu contents
-  let finalEnv = evalTricu Map.empty asts
+  case parseProgram tokens of
-  case Map.lookup "__result" finalEnv of
+    Left err -> errorWithoutStackTrace (handleParseError err)
-    Just finalResult -> return finalResult
+    Right ast -> do
-    Nothing -> errorWithoutStackTrace "No expressions to evaluate found"
+      processedAst <- preprocessFile filePath
+      let finalEnv = evalTricu Map.empty processedAst
+      case extractMain finalEnv of
+        Right result -> return result
+        Left err -> errorWithoutStackTrace err
 
 evaluateFile :: FilePath -> IO Env
 evaluateFile filePath = do
   contents <- readFile filePath
-  let asts = parseTricu contents
+  let tokens = lexTricu contents
-  pure $ evalTricu Map.empty asts
+  case parseProgram tokens of
+    Left err -> errorWithoutStackTrace (handleParseError err)
+    Right ast -> do
+      ast <- preprocessFile filePath
+      pure $ evalTricu Map.empty ast
 
 evaluateFileWithContext :: Env -> FilePath -> IO Env
 evaluateFileWithContext env filePath = do
   contents <- readFile filePath
-  let asts = parseTricu contents
+  let tokens = lexTricu contents
-  pure $ evalTricu env asts
+  case parseProgram tokens of
+    Left err -> errorWithoutStackTrace (handleParseError err)
+    Right ast -> do
+      ast <- preprocessFile filePath
+      pure $ evalTricu env ast
+
+preprocessFile :: FilePath -> IO [TricuAST]
+preprocessFile p = preprocessFile' Set.empty p p
+
+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
+  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
+
+makeRelativeTo :: FilePath -> FilePath -> FilePath
+makeRelativeTo f i =
+    let d = takeDirectory f
+    in normalise $ d </> i
+
+nsDefinitions :: String -> [TricuAST] -> [TricuAST]
+nsDefinitions moduleName = map (nsDefinition moduleName)
+
+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
+
+nsBody :: String -> TricuAST -> TricuAST
+nsBody 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
+
+nsBodyScoped :: String -> [String] -> TricuAST -> TricuAST
+nsBodyScoped 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)
+  SDef name innerArgs innerBody ->
+    SDef (nsVariable moduleName name) innerArgs
+         (nsBodyScoped 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

src/Lexer.hs

@@ -3,6 +3,7 @@ module Lexer where
 import Research
 
 import Control.Monad               (void)
+import Data.Functor                (($>))
 import Data.Void
 import Text.Megaparsec
 import Text.Megaparsec.Char hiding (space)
@@ -12,21 +13,111 @@ import qualified Data.Set as Set
 
 type Lexer = Parsec Void String
 
+tricuLexer :: Lexer [LToken]
+tricuLexer = do
+  sc
+  header <- many $ do
+    tok <- choice
+      [ try lImport
+      , lnewline
+      ]
+    sc
+    pure tok
+  tokens <- many $ do
+    tok <- choice tricuLexer'
+    sc
+    pure tok
+  sc
+  eof
+  pure (header ++ tokens)
+  where
+    tricuLexer' =
+      [ try lnewline
+      , try namespace
+      , try dot
+      , try identifier
+      , try keywordT
+      , try integerLiteral
+      , try stringLiteral
+      , assign
+      , colon
+      , backslash
+      , openParen
+      , closeParen
+      , openBracket
+      , closeBracket
+      ]
+
+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 *> pure LKeywordT
+keywordT = string "t" *> notFollowedBy alphaNumChar $> LKeywordT
 
 identifier :: Lexer LToken
 identifier = do
-  first <- letterChar <|> char '_'
+  first <- lowerChar <|> char '_'
   rest  <- many $ letterChar
-              <|> digitChar 
+              <|> digitChar <|> char '_' <|> char '-' <|> char '?'
-              <|> char '_' <|> char '-' <|> char '?' <|> char '!'
+              <|> char '$'  <|> char '#' <|> char '@' <|> char '%'
-              <|> char '$' <|> char '#' <|> char '@' <|> char '%'
   let name = first : rest
-  if (name == "t" || name == "__result")
+  if name == "t" || name == "!result"
-    then fail "Keywords (`t`, `__result`) cannot be used as an identifier"
+    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
+
+backslash :: Lexer LToken
+backslash = char '\\' $> LBackslash
+
+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
@@ -39,63 +130,3 @@ stringLiteral = do
   char '"' --"
   return (LStringLiteral content)
 
-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
-  tokens <- many $ do
-    tok <- choice tricuLexer'
-    sc
-    pure tok
-  sc
-  eof
-  pure tokens
-    where
-      tricuLexer' = 
-        [ try lnewline
-        , try identifier
-        , try keywordT
-        , try integerLiteral
-        , try stringLiteral
-        , assign
-        , colon
-        , backslash
-        , openParen
-        , closeParen
-        , openBracket
-        , closeBracket
-        ]
-
-lexTricu :: String -> [LToken]
-lexTricu input = case runParser tricuLexer "" input of
-  Left err -> errorWithoutStackTrace $ "Lexical error:\n" ++ errorBundlePretty err
-  Right tokens -> tokens

src/Main.hs

@@ -1,6 +1,6 @@
 module Main where
 
-import Eval                   (evalTricu, result)
+import Eval                   (evalTricu, mainResult, result)
 import FileEval
 import Parser                 (parseTricu)
 import REPL
@@ -8,7 +8,9 @@ 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
@@ -16,7 +18,7 @@ import qualified Data.Map as Map
 data TricuArgs
   = Repl
   | Evaluate { file :: [FilePath], form :: EvaluatedForm }
-  | Decode { file :: [FilePath] }
+  | TDecode { file :: [FilePath] }
   deriving (Show, Data, Typeable)
 
 replMode :: TricuArgs
@@ -31,7 +33,7 @@ evaluateMode = Evaluate
       \ Defaults to stdin."
       &= name "f" &= typ "FILE"
     , form = TreeCalculus &= typ "FORM"
-      &= help "Optional output form: (tree|fsl|ast|ternary|ascii).\n \
+      &= help "Optional output form: (tree|fsl|ast|ternary|ascii|decode).\n \
       \ Defaults to tricu-compatible `t` tree form."
       &= name "t"
   }
@@ -40,7 +42,7 @@ evaluateMode = Evaluate
   &= name "eval"
 
 decodeMode :: TricuArgs
-decodeMode = Decode
+decodeMode = TDecode
   { file = def
     &= help "Optional input file path to attempt decoding.\n \
     \ Defaults to stdin."
@@ -52,16 +54,17 @@ decodeMode = Decode
 
 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 "tricu Evaluator and REPL"
+    &= summary versionStr
+    &= versionArg [explicit, name "version", summary versionStr]
   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.`"
-      library <- liftIO $ evaluateFile "./lib/base.tri"
+      repl Map.empty
-      repl $ Map.delete "__result" library
     Evaluate { file = filePaths, form = form } -> do
       result <- case filePaths of
         [] -> do
@@ -70,15 +73,14 @@ main = do
         (filePath:restFilePaths) -> do
             initialEnv <- evaluateFile filePath
             finalEnv <- foldM evaluateFileWithContext initialEnv restFilePaths
-            pure $ result finalEnv
+            pure $ mainResult finalEnv
       let fRes = formatResult form result
       putStr fRes
-    Decode { file = filePaths } -> do
+    TDecode { file = filePaths } -> do
       value <- case filePaths of
         [] -> getContents
         (filePath:_) -> readFile filePath
-      library <- liftIO $ evaluateFile "./lib/base.tri"
+      putStrLn $ decodeResult $ result $ evalTricu Map.empty $ parseTricu value
-      putStrLn $ decodeResult $ result $ evalTricu library $ parseTricu value
 
 runTricu :: String -> T
 runTricu input =

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.List.NonEmpty        (toList)
-import Data.Void (Void)
+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
@@ -74,9 +74,22 @@ parseSingle input =
 parseProgramM :: ParserM [TricuAST]
 parseProgramM = do
   skipMany topLevelNewline
+  importNodes <- many (do
+    node <- parseImportM
+    skipMany topLevelNewline
+    return node)
+  skipMany topLevelNewline
   exprs <- sepEndBy parseOneExpression (some topLevelNewline)
   skipMany topLevelNewline
-  return exprs
+  return (importNodes ++ exprs)
+
+parseImportM :: ParserM TricuAST
+parseImportM = do
+  LImport filePath moduleName <- satisfyM isImport
+  pure (SImport filePath moduleName)
+  where
+    isImport (LImport _ _) = True
+    isImport _             = False
 
 parseOneExpression :: ParserM TricuAST
 parseOneExpression = scnParserM *> parseExpressionM
@@ -85,13 +98,10 @@ scnParserM :: ParserM ()
 scnParserM = skipMany $ do
   t  <- lookAhead anySingle
   st <- get
-  if | (parenDepth st > 0 || bracketDepth st > 0) && case t of
+  if | (parenDepth st > 0 || bracketDepth st > 0) && (t == LNewline) ->
-         LNewline -> True
+       void $ satisfyM (== LNewline)
-         _        -> False -> void $ satisfyM $ \case
+     | otherwise ->
-           LNewline -> True
+       fail "In nested context or no space token" <|> empty
-           _        -> False
-     | otherwise -> fail "In nested context or no space token" <|> empty
-
 
 eofM :: ParserM ()
 eofM = lift eof
@@ -109,32 +119,23 @@ parseExpressionM = choice
 
 parseFunctionM :: ParserM TricuAST
 parseFunctionM = do
-  LIdentifier name <- satisfyM $ \case
+  let ident = (\case LIdentifier _ -> True; _ -> False)
-    LIdentifier _ -> True
+  LIdentifier name <- satisfyM ident
-    _             -> False
+  args <- many $ satisfyM ident
-  args <- many $ satisfyM $ \case
-    LIdentifier _ -> True
-    _             -> False
   _    <- satisfyM (== LAssign)
   scnParserM
   body <- parseExpressionM
-  pure (SFunc name (map getIdentifier args) body)
+  pure (SDef name (map getIdentifier args) body)
 
 parseLambdaM :: ParserM TricuAST
-parseLambdaM =
+parseLambdaM = do
-  between (satisfyM (== LOpenParen)) (satisfyM (== LCloseParen)) $ do
+  let ident = (\case LIdentifier _ -> True; _ -> False)
-    _     <- satisfyM (== LBackslash)
+  _      <- satisfyM (== LBackslash)
-    param <- satisfyM $ \case
+  params <- some (satisfyM ident)
-      LIdentifier _ -> True
+  _      <- satisfyM (== LColon)
-      _             -> False
+  scnParserM
-    rest  <- many $ satisfyM $ \case
+  body  <- parseLambdaExpressionM
-      LIdentifier _ -> True
+  pure $ foldr (\param acc -> SLambda [getIdentifier param] acc) body params
-      _             -> False
-    _     <- satisfyM (== LColon)
-    scnParserM
-    body <- parseLambdaExpressionM
-    let nested = foldr (\v acc -> SLambda [getIdentifier v] acc) body rest
-    pure (SLambda [getIdentifier param] nested)
 
 parseLambdaExpressionM :: ParserM TricuAST
 parseLambdaExpressionM = choice
@@ -180,9 +181,8 @@ parseAtomicBaseM = choice
 
 parseTreeLeafM :: ParserM TricuAST
 parseTreeLeafM = do
-  _ <- satisfyM $ \case
+  let keyword = (\case LKeywordT -> True; _ -> False)
-    LKeywordT -> True
+  _ <- satisfyM keyword
-    _         -> False
   notFollowedBy $ lift $ satisfy (== LAssign)
   pure TLeaf
 
@@ -248,37 +248,45 @@ parseGroupedItemM = do
 
 parseSingleItemM :: ParserM TricuAST
 parseSingleItemM = do
-  token <- satisfyM $ \case
+  token <- satisfyM (\case LIdentifier _ -> True; LKeywordT -> True; _ -> False)
-    LIdentifier _ -> True
+  if | LIdentifier name <- token -> pure (SVar name)
-    LKeywordT     -> True
+     | token == LKeywordT        -> pure TLeaf
-    _             -> False
+     | otherwise                 -> fail "Unexpected token in list item"
-  case token of
-    LIdentifier name -> pure (SVar name)
-    LKeywordT        -> pure TLeaf
-    _                -> fail "Unexpected token in list item"
 
 parseVarM :: ParserM TricuAST
 parseVarM = do
-  LIdentifier name <- satisfyM $ \case
+  token <- satisfyM (\case
+    LNamespace _ -> True
     LIdentifier _ -> True
-    _             -> False
+    _ -> False)
-  if name == "t" || name == "__result"
+  case token of
-    then fail ("Reserved keyword: " ++ name ++ " cannot be assigned.")
+    LNamespace ns -> do
-    else pure (SVar name)
+      _ <- satisfyM (== LDot)
+      LIdentifier name <- satisfyM (\case LIdentifier _ -> True; _ -> False)
+      pure $ SVar (ns ++ "." ++ name)
+    LIdentifier name
+      | name == "t" || name == "!result" ->
+        fail ("Reserved keyword: " ++ name ++ " cannot be assigned.")
+      | otherwise -> pure (SVar name)
+    _ -> fail "Unexpected token while parsing variable"
 
 parseIntLiteralM :: ParserM TricuAST
 parseIntLiteralM = do
-  LIntegerLiteral value <- satisfyM $ \case
+  let intL = (\case LIntegerLiteral _ -> True; _ -> False)
-    LIntegerLiteral _ -> True
+  token <- satisfyM intL
-    _                 -> False
+  if | LIntegerLiteral value <- token ->
-  pure (SInt value)
+       pure (SInt value)
+     | otherwise                      ->
+       fail "Unexpected token while parsing integer literal"
 
 parseStrLiteralM :: ParserM TricuAST
 parseStrLiteralM = do
-  LStringLiteral value <- satisfyM $ \case 
+  let strL = (\case LStringLiteral _ -> True; _ -> False)
-    LStringLiteral _ -> True
+  token <- satisfyM strL
-    _ -> False
+  if | LStringLiteral value <- token ->
-  pure (SStr value)
+       pure (SStr value)
+     | otherwise                     ->
+       fail "Unexpected token while parsing string literal"
 
 getIdentifier :: LToken -> String
 getIdentifier (LIdentifier name) = name

src/REPL.hs

@@ -6,50 +6,154 @@ import Lexer
 import Parser
 import Research
 
-import Control.Exception         (SomeException, catch)
+import Control.Exception         (IOException, SomeException, catch
+                                 , displayException)
+import Control.Monad             (forM_)
+import Control.Monad.Catch       (handle, MonadCatch)
 import Control.Monad.IO.Class    (liftIO)
-import Data.Char                 (isSpace)
+import Control.Monad.Trans.Class (lift)
-import Data.List                 (dropWhile, dropWhileEnd, intercalate)
+import Control.Monad.Trans.Maybe (MaybeT(..), runMaybeT)
+import Data.Char                 (isSpace, isUpper)
+import Data.List                 (dropWhile, dropWhileEnd, isPrefixOf)
+import Data.Version (showVersion)
+import Paths_tricu (version)
 import System.Console.Haskeline
 
 import qualified Data.Map as Map
+import qualified Data.Text as T
+import qualified Data.Text.IO as T
 
 repl :: Env -> IO ()
-repl env = runInputT defaultSettings (loop env)
+repl env = runInputT settings (withInterrupt (loop env Decode))
   where
-    loop :: Env -> InputT IO ()
+    settings :: Settings IO
-    loop env = do
+    settings = Settings
-      minput <- getInputLine "tricu < "
+      { complete = completeWord Nothing " \t" completeCommands
-      if
+      , historyFile = Just "~/.local/state/tricu/history"
-        | Nothing <- minput                     -> outputStrLn "Exiting tricu"
+      , autoAddHistory = True
-        | Just s  <- minput, strip s == "!exit" -> outputStrLn "Exiting tricu"
+      }
-        | Just s  <- minput, strip s == ""      -> do
-          outputStrLn ""
-          loop env
-        | Just s  <- minput, strip s == "!load" -> 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
 
-    processInput :: Env -> String -> IO Env
+    completeCommands :: String -> IO [Completion]
-    processInput env input = do
+    completeCommands str = return $ map simpleCompletion $
+      filter (str `isPrefixOf`) commands
+      where
+        commands = [ "!exit"
+                   , "!output"
+                   , "!definitions"
+                   , "!import"
+                   , "!clear"
+                   , "!save"
+                   , "!reset"
+                   , "!version"
+                   ]
+
+    loop :: Env -> EvaluatedForm -> InputT IO ()
+    loop env form = handle (interruptHandler env form) $ do
+      minput <- getInputLine "tricu < "
+      case minput of
+        Nothing -> outputStrLn "Exiting tricu"
+        Just s
+          | strip s == "" -> loop env 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
+
+    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
       let asts   = parseTricu input
           newEnv = evalTricu env asts
-      if
+      case Map.lookup "!result" newEnv of
-        | Just r <- Map.lookup "__result" newEnv -> do
+        Just r -> do
-          putStrLn $ "tricu > " ++ decodeResult r
+          putStrLn $ "tricu > " ++ formatResult form r
-        | otherwise -> return ()
+        Nothing -> pure ()
       return newEnv
 
     errorHandler :: Env -> SomeException -> IO (Env)
@@ -60,9 +164,27 @@ repl env = runInputT defaultSettings (loop env)
     strip :: String -> String
     strip = dropWhileEnd isSpace . dropWhile isSpace
 
-decodeResult :: T -> String
+    handleSave :: Env -> EvaluatedForm -> InputT IO ()
-decodeResult tc
+    handleSave env form = do
-  | Right num  <- toNumber tc = show num
+      let fset = setComplete completeFilename defaultSettings
-  | Right str  <- toString tc = "\"" ++ str ++ "\""
+      path <- runInputT fset $
-  | Right list <- toList tc   = "[" ++ intercalate ", " (map decodeResult list) ++ "]"
+        getInputLineWithInitial "File to save < " ("", "")
-  | otherwise                 = formatResult TreeCalculus tc
+
+      case path of
+        Nothing -> do
+          outputStrLn "Save cancelled"
+          loop env form
+        Just p -> do
+          let definitions = Map.toList $ Map.delete "!result" env
+              filepath = strip p
+
+          outputStrLn "Starting save..."
+          liftIO $ writeFile filepath ""
+          outputStrLn "File created..."
+          forM_ definitions $ \(name, value) -> do
+            let content = name ++ " = " ++ formatResult TreeCalculus value ++ "\n"
+            outputStrLn $ "Writing definition: " ++ name ++ " with length " ++ show (length content)
+            liftIO $ appendFile filepath content
+          outputStrLn $ "Saved " ++ show (length definitions) ++ " definitions to " ++ p
+
+          loop env form

src/Research.hs

@@ -1,6 +1,5 @@
 module Research where
 
-import Control.Monad.State
 import Data.List                 (intercalate)
 import Data.Map                  (Map)
 import Data.Text                 (Text, replace)
@@ -19,47 +18,60 @@ data TricuAST
   | SInt Int
   | SStr String
   | SList [TricuAST]
-  | SFunc String [String] TricuAST
+  | SDef String [String] TricuAST
   | SApp TricuAST TricuAST
   | TLeaf
   | TStem TricuAST
   | TFork TricuAST TricuAST
   | SLambda [String] TricuAST
   | SEmpty
+  | SImport String String
   deriving (Show, Eq, Ord)
 
 -- Lexer Tokens
 data LToken
   = LKeywordT
   | LIdentifier String
+  | LNamespace String
   | LIntegerLiteral Int
   | LStringLiteral String
   | LAssign
   | LColon
+  | LDot
   | LBackslash
   | LOpenParen
   | LCloseParen
   | LOpenBracket
   | LCloseBracket
   | LNewline
+  | LImport String String
   deriving (Show, Eq, Ord)
 
 -- Output formats
-data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii
+data EvaluatedForm = TreeCalculus | FSL | AST | Ternary | Ascii | Decode
   deriving (Show, Data, Typeable)
 
 -- Environment containing previously evaluated TC terms
 type Env = Map.Map String T
 
--- Tree Calculus Reduction
+-- Tree Calculus Reduction Rules
+{- 
+  The t operator is left associative.
+  1.  t  t      a b       -> a
+  2.  t (t a)   b c       -> a c (b c)
+  3a. t (t a b) c t       -> a
+  3b. t (t a b) c (t u)   -> b u
+  3c. t (t a b) c (t u v) -> c u v
+-}
 apply :: T -> T -> T
-apply Leaf b                            = Stem b
+apply (Fork Leaf a)         _         = a
-apply (Stem a) b                        = Fork a b
+apply (Fork (Stem a) b) c             = apply (apply a c) (apply b c)
-apply (Fork Leaf a) _                   = a
+apply (Fork (Fork a  b) c)  Leaf      = a
-apply (Fork (Stem a1) a2) b             = apply (apply a1 b) (apply a2 b)
+apply (Fork (Fork a  b) c) (Stem u)   = apply b u
-apply (Fork (Fork a1 a2) a3) Leaf       = a1
+apply (Fork (Fork a  b) c) (Fork u v) = apply (apply c u) v
-apply (Fork (Fork a1 a2) a3) (Stem u)   = apply a2 u
+-- Left associative `t`
-apply (Fork (Fork a1 a2) a3) (Fork u v) = apply (apply a3 u) v
+apply  Leaf b                         = Stem b
+apply (Stem a) b                      = Fork a b
 
 -- Booleans
 _false :: T
@@ -73,7 +85,7 @@ _not = Fork (Fork _true (Fork Leaf _false)) Leaf
 
 -- Marshalling
 ofString :: String -> T
-ofString str = ofList (map ofNumber (map fromEnum str))
+ofString str = ofList $ map (ofNumber . fromEnum) str
 
 ofNumber :: Int -> T
 ofNumber 0 = Leaf
@@ -83,8 +95,7 @@ ofNumber n =
     (ofNumber (n `div` 2))
 
 ofList :: [T] -> T
-ofList [] = Leaf
+ofList = foldr Fork Leaf
-ofList (x:xs) = Fork x (ofList xs)
 
 toNumber :: T -> Either String Int
 toNumber Leaf = Right 0
@@ -115,13 +126,14 @@ formatResult FSL          = show
 formatResult AST          = show . toAST
 formatResult Ternary      = toTernaryString
 formatResult Ascii        = toAscii
+formatResult Decode       = decodeResult
 
 toSimpleT :: String -> String
 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"
@@ -147,4 +159,19 @@ toAscii tree = go tree "" True
         ++ go left (prefix ++ (if isLast then "    " else "|   ")) False
         ++ go right (prefix ++ (if isLast then "    " else "|   ")) True
 
--- Utility
+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

test/Spec.hs

@@ -7,12 +7,13 @@ import Parser
 import REPL
 import Research
 
-import Control.Exception (evaluate, try, SomeException)
+import Control.Exception      (evaluate, try, SomeException)
 import Control.Monad.IO.Class (liftIO)
+import Data.List              (isInfixOf)
 import Test.Tasty
 import Test.Tasty.HUnit
 import Test.Tasty.QuickCheck
-import Text.Megaparsec (runParser)
+import Text.Megaparsec        (runParser)
 
 import qualified Data.Map as Map
 import qualified Data.Set as Set
@@ -25,180 +26,218 @@ runTricu s = show $ result (evalTricu Map.empty $ parseTricu s)
 
 tests :: TestTree
 tests = testGroup "Tricu Tests"
-  [ lexerTests
+  [ lexer
-  , parserTests
+  , parser
-  , evaluationTests
+  , simpleEvaluation
-  , lambdaEvalTests
+  , lambdas
-  , libraryTests
+  , providedLibraries
-  , fileEvaluationTests
+  , fileEval
+  , modules
+  , demos
+  , decoding
   ]
 
-lexerTests :: TestTree
+lexer :: TestTree
-lexerTests = testGroup "Lexer Tests"
+lexer = 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 tricuLexer "" input @?= expect
+
   , testCase "Lex Tree Calculus terms" $ do
       let input = "t t t"
           expect = Right [LKeywordT, LKeywordT, LKeywordT]
       runParser tricuLexer "" input @?= expect
+
   , testCase "Lex escaped characters in strings" $ do
       let input = "\"hello\\nworld\""
           expect = Right [LStringLiteral "hello\\nworld"]
       runParser tricuLexer "" input @?= expect
+
   , testCase "Lex mixed literals" $ do
       let input = "t \"string\" 42"
           expect = Right [LKeywordT, LStringLiteral "string", LIntegerLiteral 42]
       runParser tricuLexer "" input @?= expect
+
   , testCase "Lex invalid token" $ do
       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 tricuLexer "" input) of
         Left _ -> assertFailure "Failed to lex input"
         Right i -> i @?= expect
+
   , testCase "Error when using invalid characters in identifiers" $ do
-        case (runParser tricuLexer "" "__result = 5") of
+        case (runParser tricuLexer "" "!result = 5") of
           Left _ -> return ()
-          Right _ -> assertFailure "Expected failure when trying to assign the value of __result"
+          Right _ -> assertFailure "Expected failure when trying to assign the value of !result"
   ]
 
-parserTests :: TestTree
+parser :: TestTree
-parserTests = testGroup "Parser Tests"
+parser = testGroup "Parser Tests"
   [ testCase "Error when assigning a value to T" $ do
       let tokens = lexTricu "t = x" 
       case parseSingleExpr tokens of
         Left  _ -> return ()
         Right _ -> assertFailure "Expected failure when trying to assign the value of T"
+
   , testCase "Parse function definitions" $ do
       let input = "x = (\\a b c : a)"
-          expect = SFunc "x" [] (SLambda ["a"] (SLambda ["b"] (SLambda ["c"] (SVar "a"))))
+          expect = SDef "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"
           expect = SApp (SApp TLeaf (SApp TLeaf TLeaf)) TLeaf
       parseSingle input @?= expect
+
   , testCase "Parse sequential Tree Calculus terms" $ do
       let input = "t t t"
           expect = SApp (SApp TLeaf TLeaf) TLeaf
       parseSingle input @?= expect
+
   , testCase "Parse mixed list literals" $ do
       let input = "[t (\"hello\") t]"
           expect = SList [TLeaf, SStr "hello", TLeaf]
       parseSingle input @?= expect
+
   , testCase "Parse function with applications" $ do
       let input  = "f = (\\x : t x)"
-          expect = SFunc "f" [] (SLambda ["x"] (SApp TLeaf (SVar "x")))
+          expect = SDef "f" [] (SLambda ["x"] (SApp TLeaf (SVar "x")))
       parseSingle input @?= expect
+
   , testCase "Parse nested lists" $ do
       let input  = "[t [(t t)]]"
           expect = SList [TLeaf,SList [SApp TLeaf TLeaf]]
       parseSingle input @?= expect
+
   , testCase "Parse complex parentheses" $ do
       let input  = "t (t t (t t))"
           expect = SApp TLeaf (SApp (SApp TLeaf TLeaf) (SApp TLeaf TLeaf))
       parseSingle input @?= expect
+
   , testCase "Parse empty list" $ do
       let input  = "[]"
           expect = SList []
       parseSingle input @?= expect
+
   , testCase "Parse multiple nested lists" $ do
       let input  = "[[t t] [t (t t)]]"
           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 ]"
           expect = SList [TLeaf, TLeaf]
       parseSingle input1 @?= expect
       parseSingle input2 @?= expect
+
   , testCase "Parse string in list" $ do
       let input  = "[(\"hello\")]"
           expect = SList [SStr "hello"]
       parseSingle input @?= expect
+
   , testCase "Parse parentheses inside list" $ do
       let input  = "[t (t t)]"
           expect = SList [TLeaf,SApp TLeaf TLeaf]
       parseSingle input @?= expect
+
   , testCase "Parse nested parentheses in function body" $ do
       let input  = "f = (\\x : t (t (t t)))"
-          expect = SFunc "f" [] (SLambda ["x"] (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf))))
+          expect = SDef "f" [] (SLambda ["x"] (SApp TLeaf (SApp TLeaf (SApp TLeaf TLeaf))))
       parseSingle input @?= expect
+
   , testCase "Parse lambda abstractions" $ do
       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)"
-          expect = SFunc "x" [] (SLambda ["a"] (SLambda ["b"] (SVar "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)"
-          expect = [SFunc "x" [] (SLambda ["a"] (SVar "a")),SApp (SVar "x") TLeaf]
+          expect = [SDef "x" [] (SLambda ["a"] (SVar "a")),SApp (SVar "x") TLeaf]
       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
   ]
 
-evaluationTests :: TestTree
+simpleEvaluation :: TestTree
-evaluationTests = testGroup "Evaluation Tests"
+simpleEvaluation = testGroup "Evaluation Tests"
   [ testCase "Evaluate single Leaf" $ do
       let input = "t"
       let ast = parseSingle input
       (result $ evalSingle Map.empty ast) @?= Leaf
+
   , testCase "Evaluate single Stem" $ do
       let input = "t t"
       let ast = parseSingle input
       (result $ evalSingle Map.empty ast) @?= Stem Leaf
+
   , testCase "Evaluate single Fork" $ do
       let input = "t t t"
       let ast = parseSingle input
       (result $ evalSingle Map.empty ast) @?= Fork Leaf Leaf
+
   , testCase "Evaluate nested Fork and Stem" $ do
       let input = "t (t t) t"
       let ast = parseSingle input
       (result $ evalSingle Map.empty ast) @?= Fork (Stem Leaf) Leaf
+
   , testCase "Evaluate `not` function" $ do
       let input = "t (t (t t) (t t t)) t"
       let ast = parseSingle input
       (result $ evalSingle Map.empty ast) @?=
         Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
+
   , testCase "Environment updates with definitions" $ do
       let input = "x = t\ny = x"
           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"
           env = evalTricu Map.empty (parseTricu input)
       (result env) @?= Stem (Stem Leaf)
+
   , testCase "Multiline input evaluation" $ do
       let input = "x = t\ny = t t\nx"
           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) @?= ofString "hello"
+
   , testCase "Evaluate list literal" $ do
       let input = "[t (t t)]"
       let ast = parseSingle input
       (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) @?= ofList []
+
   , testCase "Evaluate variable dependency chain" $ do
       let input = "x = t (t t)\n \
                   \ y = x\n \
@@ -207,10 +246,17 @@ evaluationTests = testGroup "Evaluation Tests"
                   \ variablewithamuchlongername"
           env = evalTricu Map.empty (parseTricu input)
       (result env) @?= (Stem (Stem Leaf))
-  , testCase "Evaluate variable shadowing" $ do
+
+
+  , testCase "Immutable definitions" $ do
       let input = "x = t t\nx = t\nx"
           env = evalTricu Map.empty (parseTricu input)
-      (result env) @?= Leaf
+      result <- try (evaluate (runTricu input)) :: IO (Either SomeException String)
+      case result of
+        Left  _ -> return ()
+        Right _ -> assertFailure "Expected evaluation error"
+
+
   , testCase "Apply identity to Boolean Not" $ do
       let not = "(t (t (t t) (t t t)) t)"
       let input = "x = (\\a : a)\nx " ++ not
@@ -218,194 +264,294 @@ evaluationTests = testGroup "Evaluation Tests"
       result env @?= Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
   ]
 
-lambdaEvalTests :: TestTree
+lambdas :: TestTree
-lambdaEvalTests = testGroup "Lambda Evaluation Tests"
+lambdas = 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
+
+  , testCase "Lambda applied to string literal" $ do
         let input = "f = (\\x : x)\nf \"hello\""
         runTricu input @?= "Fork (Fork Leaf (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) Leaf))))"
-   , testCase "Lambda with an integer literal" $ do
+
+
+   , testCase "Lambda applied to integer literal" $ do
         let input = "f = (\\x : x)\nf 42"
         runTricu input @?= "Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) Leaf)))))"
-   , testCase "Lambda with a list literal" $ do
+
+   , testCase "Lambda applied to list literal" $ do
         let input = "f = (\\x : x)\nf [t (t t)]"
         runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
+
+  , testCase "Lambda containing list literal" $ do
+      let input = "(\\a : [(a)]) 1"
+      runTricu input @?= "Fork (Fork (Stem Leaf) Leaf) Leaf"
   ]
 
-libraryTests :: TestTree
+providedLibraries :: TestTree
-libraryTests = testGroup "Library Tests"
+providedLibraries = testGroup "Library Tests"
-  [ testCase "K combinator 1" $ do
+  [ testCase "Triage test Leaf" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.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"
+      library <- evaluateFile "./lib/list.tri"
       let input = "test (t t)"
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Stem\""
+
   , testCase "Triage test (Fork Leaf Leaf)" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "test (t t t)"
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Fork\""
+
   , testCase "Boolean NOT: true" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? true"
           env = result $ evalTricu library (parseTricu input)
       env @?= Leaf
+
   , testCase "Boolean NOT: false" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? false"
           env = result $ evalTricu library (parseTricu input)
       env @?= Stem Leaf
+
+
   , testCase "Boolean AND TF" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
+
   , testCase "Boolean AND FT" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
+
   , testCase "Boolean AND FF" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
+
   , testCase "Boolean AND TT" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "and? (t t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
+
   , testCase "List head" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "head [(t) (t t) (t t t)]"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
+
   , testCase "List tail" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "head (tail (tail [(t) (t t) (t t t)]))"
           env = evalTricu library (parseTricu input)
       result env @?= Fork Leaf Leaf
+
   , testCase "List map" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "head (tail (map (\\a : (t t t)) [(t) (t) (t)]))"
           env = evalTricu library (parseTricu input)
       result env @?= Fork Leaf Leaf
+
   , testCase "Empty list check" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "emptyList? []"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
+
   , testCase "Non-empty list check" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "not? (emptyList? [(1) (2) (3)])"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
+
   , testCase "Concatenate strings" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
-      let input = "lconcat \"Hello, \" \"world!\""
+      let input = "append \"Hello, \" \"world!\""
           env = decodeResult $ result $ evalTricu library (parseTricu input)
       env @?= "\"Hello, world!\""
+
   , testCase "Verifying Equality" $ do
-      library <- evaluateFile "./lib/base.tri"
+      library <- evaluateFile "./lib/list.tri"
       let input = "equal? (t t t) (t t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
   ]
 
-fileEvaluationTests :: TestTree
+fileEval :: TestTree
-fileEvaluationTests = testGroup "Evaluation tests"
+fileEval = testGroup "File 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"
+      library <- liftIO $ evaluateFile "./lib/list.tri"
-      res @?= Stem Leaf
+      fEnv    <- liftIO $ evaluateFileWithContext library "./test/map.tri"
+      (mainResult fEnv) @?= Stem Leaf
+
   , testCase "Eval and decoding string" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
+      library <- liftIO $ evaluateFile "./lib/list.tri"
       res <- liftIO $ evaluateFileWithContext library "./test/string.tri"
       decodeResult (result res) @?= "\"String test!\""
   ]
+
+modules :: TestTree
+modules = testGroup "Test modules"
+  [ testCase "Detect cyclic dependencies" $ do
+      result <- try (liftIO $ evaluateFileResult "./test/cycle-1.tri") :: IO (Either SomeException T)
+      case result of
+        Left e -> do
+          let errorMsg = show e
+          if "Encountered cyclic import" `isInfixOf` errorMsg
+            then return ()
+            else assertFailure $ "Unexpected error: " ++ errorMsg
+        Right _ -> assertFailure "Expected cyclic dependencies"
+  , testCase "Module imports and namespacing" $ do
+      res <- liftIO $ evaluateFileResult "./test/namespace-A.tri"
+      res @?= Leaf
+  , testCase "Multiple imports" $ do
+      res <- liftIO $ evaluateFileResult "./test/vars-A.tri"
+      res @?= Leaf
+  , testCase "Error on unresolved variable" $ do
+      result <- try (liftIO $ evaluateFileResult "./test/unresolved-A.tri") :: IO (Either SomeException T)
+      case result of
+        Left e -> do
+          let errorMsg = show e
+          if "undefinedVar" `isInfixOf` errorMsg
+            then return ()
+            else assertFailure $ "Unexpected error: " ++ errorMsg
+        Right _ -> assertFailure "Expected unresolved variable error"
+  , testCase "Multi-level imports" $ do
+      res <- liftIO $ evaluateFileResult "./test/multi-level-A.tri"
+      res @?= Leaf
+  , 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)
+  ]
+
+
+-- All of our demo tests are also module tests
+demos :: TestTree
+demos = testGroup "Test provided demo functionality"
+  [ testCase "Structural equality demo" $ do
+      res     <- liftIO $ evaluateFileResult "./demos/equality.tri"
+      decodeResult res @?= "t t"
+  , testCase "Convert values back to source code demo" $ do
+      res     <- liftIO $ evaluateFileResult "./demos/toSource.tri"
+      decodeResult res @?= "\"(t (t (t t) (t t t)) (t t (t t t)))\""
+  , testCase "Determining the size of functions" $ do
+      res     <- liftIO $ evaluateFileResult "./demos/size.tri"
+      decodeResult res @?= "454"
+  , testCase "Level Order Traversal demo" $ do
+      res     <- liftIO $ evaluateFileResult "./demos/levelOrderTraversal.tri"
+      decodeResult res @?= "\"\n1 \n2 3 \n4 5 6 7 \n8 11 10 9 12 \""
+  ]
+
+decoding :: TestTree
+decoding = testGroup "Decoding Tests"
+  [ testCase "Decode Leaf" $ do
+      decodeResult Leaf @?= "t"
+
+  , testCase "Decode list of non-ASCII numbers" $ do
+      let input = ofList [ofNumber 1, ofNumber 14, ofNumber 6]
+      decodeResult input @?= "[1, 14, 6]"
+
+  , testCase "Decode list of ASCII numbers as a string" $ do
+      let input = ofList [ofNumber 97, ofNumber 98, ofNumber 99]
+      decodeResult input @?= "\"abc\""
+
+  , testCase "Decode small number" $ do
+      decodeResult (ofNumber 42) @?= "42"
+
+  , testCase "Decode large number" $ do
+      decodeResult (ofNumber 9999) @?= "9999"
+
+  , testCase "Decode string in list" $ do
+      let input = ofList [ofString "hello", ofString "world"]
+      decodeResult input @?= "[\"hello\", \"world\"]"
+
+  , testCase "Decode mixed list with strings" $ do
+      let input = ofList [ofString "hello", ofNumber 42, ofString "world"]
+      decodeResult input @?= "[\"hello\", 42, \"world\"]"
+
+  , testCase "Decode nested lists with strings" $ do
+      let input = ofList [ofList [ofString "nested"], ofString "string"]
+      decodeResult input @?= "[[\"nested\"], \"string\"]"
+  ]

test/ascii.tri

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

test/assignment.tri

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

test/comments-1.tri

@@ -2,7 +2,7 @@
 -- t (t t) (t (t t t))
 -- t (t t t) (t t)
 -- x = (\a : a)
-t (t t) t -- Fork (Stem Leaf) Leaf
+main = t (t t) t -- Fork (Stem Leaf) Leaf
 -- t t
 -- x
 -- x = (\a : a)

test/cycle-1.tri

@@ -0,0 +1,4 @@
+
+!import "cycle-2.tri" Cycle2
+
+cycle1 = t Cycle2.cycle2

test/cycle-2.tri

@@ -0,0 +1,4 @@
+
+!import "cycle-1.tri" Cycle1
+
+cycle2 = t Cycle1.cycle1

test/fork.tri

@@ -1 +1 @@
-t t t 
+main = t t t 

test/lambda-A.tri

@@ -0,0 +1 @@
+main = (\x : x) t

test/local-ns/1.tri

@@ -0,0 +1,4 @@
+
+!import "2.tri" Two
+
+main = Two.x

test/local-ns/2.tri

@@ -0,0 +1,2 @@
+
+!import "3.tri" !Local

test/local-ns/3.tri

@@ -0,0 +1 @@
+x = 3

test/map.tri

@@ -1,24 +1,2 @@
-false = t
+x = map (\i : append "Successfully concatenated " i) [("two strings!")]
-true = t t
+main = equal? x [("Successfully concatenated two strings!")]
-_ = 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/multi-level-A.tri

@@ -0,0 +1,2 @@
+!import "multi-level-B.tri" B
+main = B.main

test/multi-level-B.tri

@@ -0,0 +1,2 @@
+!import "multi-level-C.tri" C
+main = C.val

test/multi-level-C.tri

@@ -0,0 +1 @@
+val = t

test/named-imports/1.tri

@@ -0,0 +1,7 @@
+
+!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)

test/named-imports/2.tri

@@ -0,0 +1,2 @@
+
+x = 2

test/named-imports/3.tri

@@ -0,0 +1,2 @@
+
+x = 3

test/namespace-A.tri

@@ -0,0 +1,2 @@
+!import "namespace-B.tri" B
+main = B.x

test/namespace-B.tri

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

test/size.tri

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

test/string.tri

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

test/unresolved-A.tri

@@ -0,0 +1 @@
+main = undefinedVar

test/vars-A.tri

@@ -0,0 +1,6 @@
+
+!import "vars-B.tri" B
+
+!import "vars-C.tri" C
+
+main = B.y (C.z)

test/vars-B.tri

@@ -0,0 +1 @@
+y = \x : x

test/vars-C.tri

@@ -0,0 +1 @@
+z = t

tricu.cabal

@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           tricu
-version:        0.7.0
+version:        0.18.1
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co
@@ -26,10 +26,13 @@ executable tricu
     base >=4.7
     , cmdargs
     , containers
+    , exceptions
+    , filepath
     , haskeline
     , megaparsec
     , mtl
     , text
+    , transformers
   other-modules:
     Eval
     FileEval
@@ -52,6 +55,8 @@ test-suite tricu-tests
     base
     , cmdargs
     , containers
+    , exceptions
+    , filepath
     , haskeline
     , megaparsec
     , mtl
@@ -59,6 +64,7 @@ test-suite tricu-tests
     , tasty-hunit
     , tasty-quickcheck
     , text
+    , transformers
   default-language:    Haskell2010
   other-modules:
     Eval