Remove Nix caching that can't work due to /nix/store permissions

Adds support for several special characters in identifiers. Adds a demo
for converting values to source code and another for checking equality.
Updates the existing demo and tests to reflect new names for functions
returning booleans.

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

@@ -1,86 +1,69 @@
-name: Test and Build
+name: Test, Build, and Release
 
 on: 
   push:
-    branches:
+    tags:
-      - main
+      - '*'
-  pull_request:
-    types:
-      - opened
-      - synchronize
 
 jobs:
   test:
     container:
-      image: docker.matri.cx/nix-runner:latest
+      image: docker.matri.cx/nix-runner:v0.1.0
       credentials:
         username: ${{ secrets.REGISTRY_USERNAME }}
         password: ${{ secrets.REGISTRY_PASSWORD }}
     steps:
-      - name: Checkout code
+      - uses: actions/checkout@v3
-        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
 
       - name: Set up cache for Cabal
         uses: actions/cache@v4
         with:
           path: |
-            ~/.cabal
+            ~/.cache/cabal
-            ~/.ghc
+            ~/.config/cabal
-          key: cabal-${{ runner.os }}-${{ hashFiles('tricu.cabal') }}
+            ~/.local/state/cabal
+          key: cabal-${{ hashFiles('tricu.cabal') }}
           restore-keys: |
-            cabal-${{ runner.os }}-
+            cabal-
-
-      - name: Set up cache for Nix
-        uses: actions/cache@v4
-        with:
-          path: |
-            /nix/store
-            /nix/var/nix/cache
-          key: nix-${{ runner.os }}-${{ hashFiles('flake.lock') }}
-          restore-keys: |
-            nix-${{ runner.os }}-
 
       - name: Initialize Cabal and update package list
         run: |
           nix develop --command cabal update
 
-      - name: Install dependencies and run tests
+      - name: Run test suite
         run: |
           nix develop --command cabal test
 
   build:
     needs: test
     container:
-      image: docker.matri.cx/nix-runner:latest
+      image: docker.matri.cx/nix-runner:v0.1.0
       credentials:
         username: ${{ secrets.REGISTRY_USERNAME }}
         password: ${{ secrets.REGISTRY_PASSWORD }}
     steps:
-      - name: Checkout code
+      - uses: actions/checkout@v3
-        uses: actions/checkout@v3
-
-      - name: Set up cache for Cabal
-        uses: actions/cache@v4
         with:
-          path: |
+          fetch-depth: 0
-            ~/.cabal
-            ~/.ghc
-          key: cabal-${{ runner.os }}-${{ hashFiles('tricu.cabal') }}
-          restore-keys: |
-            cabal-${{ runner.os }}-
 
-      - 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-${{ runner.os }}-${{ hashFiles('flake.lock') }}
-          restore-keys: |
-            nix-${{ runner.os }}-
-
-      - name: Build binary
         run: |
           nix build
-          ls -alh ./result/bin/tricu
+          cp -L ./result/bin/tricu ./tricu
+          chmod 755 ./tricu
+          nix develop --command upx ./tricu
   
+      - name: Setup go for release action
+        uses: actions/setup-go@v5
+        with:
+          go-version: '>=1.20.1'
+  
+      - name: Release binary
+        uses: https://gitea.com/actions/release-action@main
+        with:
+          files: |-
+            ./tricu
+          api_key: '${{ secrets.RELEASE_TOKEN }}'
+          pre_release: true

README.md

@@ -16,7 +16,7 @@ These features move us cleanly out of the [turing tarpit](https://en.wikipedia.o
 
 tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)`. This project was named "sapling" until I discovered the name is already being used for other (completely unrelated) programming language development projects.
 
-## What does it look like?
+## REPL examples
 
 ```
 tricu < -- Anything after `--` on a single line is a comment
@@ -29,11 +29,11 @@ tricu > "Hello,  world!"
 tricu < -- Intensionality! We can inspect the structure of a function.
 tricu < triage = (\a b c : t (t a b) c)
 tricu < test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
-tricu < test t t
+tricu < test (t t)
 tricu > "Stem"
-tricu < -- We can even write a function to convert a function to source code
+tricu < -- We can even convert a term back to source code (/demos/toSource.tri)
-tricu < toTString id
+tricu < toSource not?
-tricu > "t (t (t t)) t"
+tricu > "(t (t (t t) (t t t)) (t t (t t t)))"
 ```
 
 ## Installation and Use
@@ -79,4 +79,4 @@ tricu decode [OPTIONS]
 
 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

@@ -0,0 +1,24 @@
+false = t
+true  = t t
+
+triage = (\a b c : t (t a b) c)
+
+matchBool = (\ot of : triage
+  of
+  (\_ : ot)
+  (\_ _ : ot)
+)
+
+not_TC?     = t (t (t t) (t t t)) (t t (t t t))
+not_Lambda? = matchBool false true
+
+areEqual? = equal not_TC not_Lambda
+
+true_TC?  = not_TC false
+false_TC? = not_TC true
+
+true_Lambda?  = not_Lambda false
+false_Lambda? = not_Lambda true
+
+areTrueEqual?  = equal true_TC  true_Lambda
+areFalseEqual? = equal false_TC false_Lambda

demos/levelOrderTraversal.tri

@@ -17,20 +17,15 @@
 --   4   5    6
 --
 
-isLeaf = (\node : 
+label = (\node : head node)
-  lOr 
-    (emptyList node) 
-    (emptyList (tail node)))
 
-getLabel = (\node : head node)
+left  = (\node : if (emptyList node) 
-
-getLeft  = (\node : if (emptyList node) 
   [] 
   (if (emptyList (tail node)) 
     [] 
     (head (tail node))))
 
-getRight = (\node : if (emptyList node) 
+right = (\node : if (emptyList node) 
   [] 
   (if (emptyList (tail node)) 
     [] 
@@ -40,11 +35,11 @@ getRight = (\node : if (emptyList node)
 
 processLevel = y (\self queue : if (emptyList queue) 
   [] 
-  (pair (map getLabel queue) (self (filter 
+  (pair (map label queue) (self (filter 
     (\node : not (emptyList node)) 
-      (lconcat (map getLeft queue) (map getRight queue))))))
+      (lconcat (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) 
   "" 
@@ -52,12 +47,19 @@ toLineString = y (\self levels : if (emptyList levels)
     (lconcat (map (\x : lconcat x " ") (head levels)) "") 
     (if (emptyList (tail levels)) "" (lconcat (t (t 10 t) t) (self (tail levels))))))
 
-levelOrderToString = (\s : toLineString (levelOrderTraversal s))
+levelOrderToString = (\s : toLineString (levelOrderTraversal_ s))
 
 flatten = foldl (\acc x : lconcat acc x) ""
-flatLOT = (\s : lconcat (t 10 t) (flatten (levelOrderToString s)))
 
-exampleOne = flatLOT [("1") [("2") [("4") t t] t] [("3") [("5") t t] [("6") t t]]]
+levelOrderTraversal = (\s : lconcat (t 10 t) (flatten (levelOrderToString s)))
-exampleTwo = flatLOT [("1") [("2") [("4") [("8") t t] [("9") t t]] [("6") [("10") t t] [("12") t t]]] [("3") [("5") [("11") t t] t] [("7") t t]]]
 
-exampleOne
+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]]] 
+                                 [("3") [("5") [("11") t t] t] [("7") t t]]]
+
+exampleTwo

demos/toSource.tri

@@ -0,0 +1,46 @@
+-- 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 
+-- 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)
+
+-- Base case of a single Leaf
+sourceLeaf = t (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.
+
+-- 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.
+
+-- Wrapper around triage 
+toSource_ = y (\self arg :
+  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 "")
+
+exampleOne = toSource true -- OUT: "(t t)"
+exampleTwo = toSource not  -- OUT: "(t (t (t t) (t t t)) (t t (t t t)))"

flake.nix

@@ -32,10 +32,11 @@
         defaultPackage = self.packages.${system}.default;
 
         devShells.default = pkgs.mkShell {
-          buildInputs = with pkgs.haskellPackages; [
+          buildInputs = with pkgs; [
-            cabal-install
+            haskellPackages.cabal-install
-            ghcid
+            haskellPackages.ghcid
             customGHC
+            upx
           ];
           inputsFrom = builtins.attrValues self.packages.${system};
         };

lib/base.tri

@@ -15,8 +15,11 @@ y = yi iC
 yC    = yi iD
 yD    = yi iE
 id    = (\a : a)
-triage = (\a b c : t (t a b) c)
 pair  = t
+if    = (\cond then else : t (t else (t t then)) t cond)
+
+triage = (\a b c : t (t a b) c)
+test   = triage "Leaf" (\_ : "Stem") (\_ _ : "Fork")
 
 matchBool = (\ot of : triage 
   of 
@@ -36,21 +39,19 @@ matchPair = (\op : triage
   op
 )
 
-not = matchBool false true
+not? = matchBool false true
-and = matchBool id (\z : false)
+and? = matchBool id (\_ : false)
-if = (\cond then else : t (t else (t t then)) t cond)
+emptyList? = matchList true (\_ _ : false)
-test = triage "Leaf" (\z : "Stem") (\a b : "Fork")
 
-emptyList = matchList true (\y z : false)
+head = matchList t (\head _ : head)
-head = matchList t (\hd tl : hd)
+tail = matchList t (\_ tail : tail)
-tail = matchList t (\hd tl : tl)
 
 lconcat = y (\self : matchList 
   (\k : k) 
   (\h r k : pair h (self r k)))
 
 lAnd = (triage 
-  (\x : false) 
+  (\_     : false) 
   (\_ x   : x) 
   (\_ _ x : x)
 )
@@ -58,36 +59,38 @@ lAnd = (triage
 lOr = (triage 
   (\x     : x) 
   (\_ _   : true) 
-  (\_ _ x : true)
+  (\_ _ _ : true)
 )
 
-hmap = y (\self : 
+map_ = y (\self : 
   matchList 
-    (\f : t) 
+    (\_ : t) 
-    (\hd tl f : pair 
+    (\head tail f : pair (f head) (self tail f)))
-                  (f hd) 
+map = (\f l : map_ l f)
-                  (self tl f)))
-map = (\f l : hmap l f)
 
-equal = y (\self : triage 
+equal? = y (\self : triage 
   (triage 
     true 
-    (\z : false) 
+    (\_   : false) 
-    (\y z : false)) 
+    (\_ _ : false)) 
-  (\ax : triage 
+  (\ax : 
+    triage 
       false 
       (self ax) 
-          (\y z : false)) 
+      (\_ _ : false)) 
-  (\ax ay : triage 
+  (\ax ay : 
+    triage 
       false 
-              (\z : false) 
+      (\_ : false) 
       (\bx by : lAnd (self ax bx) (self ay by))))
 
-hfilter = y (\self : matchList (\f : t) (\hd tl f : matchBool (t hd) i (f hd) (self tl f)))
+filter_ = y (\self : matchList 
-filter  = (\f l : hfilter l f)
+  (\_ : t) 
+  (\head tail f : matchBool (t head) i (f head) (self tail f)))
+filter  = (\f l : filter_ l f)
 
-hfoldl  = y (\self f l x : matchList (\acc : acc) (\hd tl acc : self f tl (f acc hd)) l x)
+foldl_ = y (\self f l x : matchList (\acc : acc) (\head tail acc : self f tail (f acc head)) l x)
-foldl   = (\f x l : hfoldl f l x)
+foldl  = (\f x l : foldl_ f l x)
 
-hfoldr  = y (\self x f l : matchList x (\hd tl : f (self x f tl) hd) l)
+foldr_ = y (\self x f l : matchList x (\head tail : f (self x f tail) head) l)
-foldr   = (\f x l : hfoldr x f l)
+foldr  = (\f x l : foldr_ x f l)

src/Lexer.hs

@@ -18,7 +18,10 @@ keywordT = string "t" *> notFollowedBy alphaNumChar *> pure LKeywordT
 identifier :: Lexer LToken
 identifier = do
   first <- letterChar <|> char '_'
-  rest <- many (letterChar <|> char '_' <|> char '-' <|> digitChar)
+  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"

src/Parser.hs

@@ -12,7 +12,8 @@ import Text.Megaparsec.Error (ParseErrorBundle, errorBundlePretty)
 import qualified Data.Set as Set
 
 data PState = PState
-  { depth :: Int
+  { parenDepth  :: Int
+  , bracketDepth :: Int
   } deriving (Show)
 
 type ParserM = StateT PState (Parsec Void [LToken])
@@ -24,24 +25,33 @@ satisfyM f = do
   return token
 
 updateDepth :: LToken -> PState -> PState
-updateDepth LOpenParen  st = st { depth = depth st + 1 }
+updateDepth LOpenParen    st = st { parenDepth   = parenDepth st   + 1 }
-updateDepth LCloseParen st = st { depth = max 0 (depth st - 1) }
+updateDepth LOpenBracket  st = st { bracketDepth = bracketDepth st + 1 }
+updateDepth LCloseParen   st = st { parenDepth   = parenDepth st   - 1 }
+updateDepth LCloseBracket st = st { bracketDepth = bracketDepth st - 1 }
 updateDepth _ st = st
 
 topLevelNewline :: ParserM ()
 topLevelNewline = do
   st <- get
-  if depth st == 0
+  if parenDepth st == 0 && bracketDepth st == 0
     then void (satisfyM (== LNewline))
-    else fail "Top-level exit in paren context"
+    else fail "Top-level exit in nested context (paren or bracket)"
 
 parseProgram :: [LToken] -> Either (ParseErrorBundle [LToken] Void) [TricuAST]
 parseProgram tokens =
-  runParser (evalStateT parseProgramM (PState 0)) "" tokens
+  runParser (evalStateT (parseProgramM <* finalizeDepth <* eof) (PState 0 0)) "" tokens
 
 parseSingleExpr :: [LToken] -> Either (ParseErrorBundle [LToken] Void) TricuAST
 parseSingleExpr tokens =
-  runParser (evalStateT (scnParserM *> parseExpressionM <* eofM) (PState 0)) "" tokens
+  runParser (evalStateT (scnParserM *> parseExpressionM <* finalizeDepth <* eof) (PState 0 0)) "" tokens
+
+finalizeDepth :: ParserM ()
+finalizeDepth = do
+  st <- get
+  case (parenDepth st, bracketDepth st) of
+    (0, 0) -> pure ()
+    (p, b) -> fail $ "Unmatched tokens: " ++ show (p, b)
 
 parseTricu :: String -> [TricuAST]
 parseTricu input =
@@ -49,7 +59,7 @@ parseTricu input =
     [] -> []
     toks ->
       case parseProgram toks of
-        Left err   -> error (handleParseError err)
+        Left err   -> errorWithoutStackTrace (handleParseError err)
         Right asts -> asts
 
 parseSingle :: String -> TricuAST
@@ -58,7 +68,7 @@ parseSingle input =
     [] -> SEmpty
     toks ->
       case parseSingleExpr toks of
-        Left err -> error (handleParseError err)
+        Left err -> errorWithoutStackTrace (handleParseError err)
         Right ast -> ast
 
 parseProgramM :: ParserM [TricuAST]
@@ -75,10 +85,13 @@ scnParserM :: ParserM ()
 scnParserM = skipMany $ do
   t  <- lookAhead anySingle
   st <- get
-  if depth st > 0 && isNewline t
+  if | (parenDepth st > 0 || bracketDepth st > 0) && case t of
-    then void (satisfyM isNewline)
+         LNewline -> True
-    else
+         _        -> False -> void $ satisfyM $ \case
-      fail "In paren context or no space token" <|> empty
+           LNewline -> True
+           _        -> False
+     | otherwise -> fail "In nested context or no space token" <|> empty
+
 
 eofM :: ParserM ()
 eofM = lift eof
@@ -96,18 +109,27 @@ parseExpressionM = choice
 
 parseFunctionM :: ParserM TricuAST
 parseFunctionM = do
-  LIdentifier name <- satisfyM isIdentifier
+  LIdentifier name <- satisfyM $ \case
-  args <- many (satisfyM isIdentifier)
+    LIdentifier _ -> True
+    _             -> False
+  args <- many $ satisfyM $ \case
+    LIdentifier _ -> True
+    _             -> False
   _    <- satisfyM (== LAssign)
   scnParserM
   body <- parseExpressionM
   pure (SFunc name (map getIdentifier args) body)
 
 parseLambdaM :: ParserM TricuAST
-parseLambdaM = between (satisfyM (== LOpenParen)) (satisfyM (== LCloseParen)) $ do
+parseLambdaM =
+  between (satisfyM (== LOpenParen)) (satisfyM (== LCloseParen)) $ do
     _     <- satisfyM (== LBackslash)
-  param   <- satisfyM isIdentifier
+    param <- satisfyM $ \case
-  rest    <- many (satisfyM isIdentifier)
+      LIdentifier _ -> True
+      _             -> False
+    rest  <- many $ satisfyM $ \case
+      LIdentifier _ -> True
+      _             -> False
     _     <- satisfyM (== LColon)
     scnParserM
     body <- parseLambdaExpressionM
@@ -158,8 +180,10 @@ parseAtomicBaseM = choice
 
 parseTreeLeafM :: ParserM TricuAST
 parseTreeLeafM = do
-  _ <- satisfyM isKeywordT
+  _ <- satisfyM $ \case
-  notFollowedBy (lift (satisfy (== LAssign)))
+    LKeywordT -> True
+    _         -> False
+  notFollowedBy $ lift $ satisfy (== LAssign)
   pure TLeaf
 
 parseTreeTermM :: ParserM TricuAST
@@ -201,7 +225,10 @@ parseLiteralM = choice
 parseListLiteralM :: ParserM TricuAST
 parseListLiteralM = do
   _        <- satisfyM (== LOpenBracket)
-  elements <- many parseListItemM
+  elements <- many $ do
+    scnParserM
+    parseListItemM
+  scnParserM
   _        <- satisfyM (== LCloseBracket)
   pure (SList elements)
 
@@ -221,7 +248,10 @@ parseGroupedItemM = do
 
 parseSingleItemM :: ParserM TricuAST
 parseSingleItemM = do
-  token <- satisfyM isListItem
+  token <- satisfyM $ \case
+    LIdentifier _ -> True
+    LKeywordT     -> True
+    _             -> False
   case token of
     LIdentifier name -> pure (SVar name)
     LKeywordT        -> pure TLeaf
@@ -229,71 +259,46 @@ parseSingleItemM = do
 
 parseVarM :: ParserM TricuAST
 parseVarM = do
-  LIdentifier name <- satisfyM isIdentifier
+  LIdentifier name <- satisfyM $ \case
+    LIdentifier _ -> True
+    _             -> False
   if name == "t" || name == "__result"
     then fail ("Reserved keyword: " ++ name ++ " cannot be assigned.")
     else pure (SVar name)
 
 parseIntLiteralM :: ParserM TricuAST
 parseIntLiteralM = do
-  LIntegerLiteral value <- satisfyM isIntegerLiteral
+  LIntegerLiteral value <- satisfyM $ \case
+    LIntegerLiteral _ -> True
+    _                 -> False
   pure (SInt value)
 
 parseStrLiteralM :: ParserM TricuAST
 parseStrLiteralM = do
-  LStringLiteral value <- satisfyM isStringLiteral
+  LStringLiteral value <- satisfyM $ \case 
+    LStringLiteral _ -> True
+    _ -> False
   pure (SStr value)
 
-isKeywordT :: LToken -> Bool
-isKeywordT LKeywordT = True
-isKeywordT _         = False
-
-isIdentifier :: LToken -> Bool
-isIdentifier (LIdentifier _) = True
-isIdentifier _               = False
-
-isIntegerLiteral :: LToken -> Bool
-isIntegerLiteral (LIntegerLiteral _) = True
-isIntegerLiteral _                   = False
-
-isStringLiteral :: LToken -> Bool
-isStringLiteral (LStringLiteral _)   = True
-isStringLiteral _                    = False
-
-isLiteral :: LToken -> Bool
-isLiteral (LIntegerLiteral _) = True
-isLiteral (LStringLiteral _)  = True
-isLiteral _                   = False
-
-isListItem :: LToken -> Bool
-isListItem (LIdentifier _) = True
-isListItem LKeywordT       = True
-isListItem _               = False
-
-isNewline :: LToken -> Bool
-isNewline LNewline = True
-isNewline _        = False
-
 getIdentifier :: LToken -> String
 getIdentifier (LIdentifier name) = name
-getIdentifier _                  = error "Expected identifier"
+getIdentifier _                  = errorWithoutStackTrace "Expected identifier"
 
 handleParseError :: ParseErrorBundle [LToken] Void -> String
 handleParseError bundle =
   let errors = bundleErrors bundle
-      errorList     = Data.List.NonEmpty.toList errors
+      formattedErrors = map formatError (Data.List.NonEmpty.toList errors)
-      formattedErrs = map showError errorList
+  in unlines ("Parse error(s) encountered:" : formattedErrors)
-  in unlines ("Parse error(s) encountered:" : formattedErrs)
-
-showError :: ParseError [LToken] Void -> String
-showError (TrivialError offset (Just (Tokens tokenStream)) expected) =
-  "Parse error at offset " ++ show offset
-    ++ ": unexpected token " ++ show tokenStream
-    ++ ", expected one of " ++ show (Set.toList expected)
-showError (FancyError offset fancy) =
-  "Parse error at offset " ++ show offset ++ ":\n "
-    ++ unlines (map show (Set.toList fancy))
-showError (TrivialError offset Nothing expected) =
-  "Parse error at offset " ++ show offset
-    ++ ": expected one of " ++ show (Set.toList expected)
 
+formatError :: ParseError [LToken] Void -> String
+formatError (TrivialError offset unexpected expected) =
+  let unexpectedMsg = case unexpected of
+        Just x  -> "unexpected token " ++ show x
+        Nothing -> "unexpected end of input"
+      expectedMsg = if null expected
+        then ""
+        else "expected " ++ show (Set.toList expected)
+  in "Parse error at offset " ++ show offset ++ ": " ++ unexpectedMsg ++
+     if null expectedMsg then "" else " " ++ expectedMsg
+formatError (FancyError offset _) =
+  "Parse error at offset " ++ show offset ++ ": unexpected FancyError"

test/Spec.hs

@@ -308,7 +308,7 @@ libraryTests = testGroup "Library Tests"
       result env @?= Fork (Stem (Stem Leaf)) (Stem Leaf)
   , testCase "I combinator" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "i not"
+      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
@@ -328,32 +328,32 @@ libraryTests = testGroup "Library Tests"
       env @?= "\"Fork\""
   , testCase "Boolean NOT: true" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "not true"
+      let input = "not? true"
           env = result $ evalTricu library (parseTricu input)
       env @?= Leaf
   , testCase "Boolean NOT: false" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "not false"
+      let input = "not? false"
           env = result $ evalTricu library (parseTricu input)
       env @?= Stem Leaf
   , testCase "Boolean AND TF" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "and (t t) (t)"
+      let input = "and? (t t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
   , testCase "Boolean AND FT" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "and (t) (t t)"
+      let input = "and? (t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
   , testCase "Boolean AND FF" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "and (t) (t)"
+      let input = "and? (t) (t)"
           env = evalTricu library (parseTricu input)
       result env @?= Leaf
   , testCase "Boolean AND TT" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "and (t t) (t t)"
+      let input = "and? (t t) (t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
   , testCase "List head" $ do
@@ -373,12 +373,12 @@ libraryTests = testGroup "Library Tests"
       result env @?= Fork Leaf Leaf
   , testCase "Empty list check" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "emptyList []"
+      let input = "emptyList? []"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
   , testCase "Non-empty list check" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "not (emptyList [(1) (2) (3)])"
+      let input = "not? (emptyList? [(1) (2) (3)])"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
   , testCase "Concatenate strings" $ do
@@ -388,7 +388,7 @@ libraryTests = testGroup "Library Tests"
       env @?= "\"Hello, world!\""
   , testCase "Verifying Equality" $ do
       library <- evaluateFile "./lib/base.tri"
-      let input = "equal (t t t) (t t t)"
+      let input = "equal? (t t t) (t t t)"
           env = evalTricu library (parseTricu input)
       result env @?= Stem Leaf
   ]

tricu.cabal

@@ -1,7 +1,7 @@
 cabal-version: 1.12
 
 name:           tricu
-version:        0.6.0
+version:        0.7.0
 description:    A micro-language for exploring Tree Calculus
 author:         James Eversole
 maintainer:     james@eversole.co
@@ -18,6 +18,7 @@ executable tricu
       src
   default-extensions:
       DeriveDataTypeable
+      LambdaCase
       MultiWayIf
       OverloadedStrings
   ghc-options: -threaded -rtsopts -with-rtsopts=-N -optl-pthread -fPIC
@@ -44,6 +45,7 @@ test-suite tricu-tests
   hs-source-dirs:      test, src
   default-extensions:
       DeriveDataTypeable
+      LambdaCase
       MultiWayIf
       OverloadedStrings
   build-depends: