tricu/test/Spec.hs

module Main where

import Eval
import Lexer
import Library
import Parser
import Research
import Control.Exception (evaluate, try, SomeException)
import Test.Tasty
import Test.Tasty.HUnit
import Test.Tasty.QuickCheck
import Text.Megaparsec (runParser)

import qualified Data.Map as Map
import qualified Data.Set as Set

main :: IO ()
main = defaultMain tests

runTricu :: String -> String
runTricu s = show $ result (evalTricu Map.empty $ parseTricu s)

tests :: TestTree
tests = testGroup "Tricu Tests"
  [ lexerTests
  , parserTests
  , integrationTests
  , evaluationTests
  , lambdaEvalTests
  , propertyTests
  ]

lexerTests :: TestTree
lexerTests = testGroup "Lexer Tests"
  [ testCase "Lex simple identifiers" $ do
      let input = "x a b = a"
          expect = Right [LIdentifier "x", LIdentifier "a", LIdentifier "b", LAssign, LIdentifier "a"]
      runParser 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
          Left _ -> return ()
          Right _ -> assertFailure "Expected failure when trying to assign the value of __result"
  ]

parserTests :: TestTree
parserTests = testGroup "Parser Tests"
  [ --testCase "Error when parsing incomplete definitions" $ do
    --  let input = lexTricu "x = "
    --  case (runParser parseExpression "" input) of
    --    Left _ -> return ()
    --    Right _ -> assertFailure "Expected failure on invalid input"
  testCase "Error when assigning a value to T" $ do
      let input = lexTricu "t = x"
      case (runParser parseExpression "" input) 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"))))
      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")))
      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))))
      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")))
      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]
      parseTricu input @?= expect
  ]

integrationTests :: TestTree
integrationTests = testGroup "Integration Tests"
  [ testCase "Combine lexer and parser" $ do
      let input = "x = t t t"
          expect = SFunc "x" [] (SApp (SApp TLeaf TLeaf) TLeaf)
      parseSingle input @?= expect
  , testCase "Complex Tree Calculus expression" $ do
      let input = "t (t t t) t"
          expect = SApp (SApp TLeaf (SApp (SApp TLeaf TLeaf) TLeaf)) TLeaf
      parseSingle input @?= expect
  ]

evaluationTests :: TestTree
evaluationTests = 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 \
                  \ z = y\n \
                  \ variablewithamuchlongername = z\n \
                  \ variablewithamuchlongername"
          env = evalTricu Map.empty (parseTricu input)
      (result env) @?= (Stem (Stem Leaf))
  , testCase "Evaluate variable shadowing" $ do
      let input = "x = t t\nx = t\nx"
          env = evalTricu Map.empty (parseTricu input)
      (result env) @?= Leaf
    , testCase "Apply identity to Boolean Not" $ do
      let not = "(t (t (t t) (t t t)) t)"
      let input = "x = (\\a : a)\nx " ++ not
          env = evalTricu Map.empty (parseTricu input)
      result env @?= Fork (Fork (Stem Leaf) (Fork Leaf Leaf)) Leaf
    , testCase "Constant function matches" $ do
      let input = "k = (\\a b : a)\nk (t t) t"
          env = evalTricu Map.empty (parseTricu input)
      result env @?= Stem Leaf
   , testCase "Boolean AND_ TF" $ do
      let input = "and (t t) (t)"
          env = evalTricu library (parseTricu input)
      result env @?= Leaf
   , testCase "Boolean AND_ FT" $ do
      let input = "and (t) (t t)"
          env = evalTricu library (parseTricu input)
      result env @?= Leaf
   , testCase "Boolean AND_ FF" $ do
      let input = "and (t) (t)"
          env = evalTricu library (parseTricu input)
      result env @?= Leaf
    , testCase "Boolean AND_ TT" $ do
      let input = "and (t t) (t t)"
          env = evalTricu library (parseTricu input)
      result env @?= Stem Leaf
    , testCase "Verifying Equality" $ do
      let input = "equal (t t t) (t t t)"
          env = evalTricu library (parseTricu input)
      result env @?= Stem Leaf
  ]

lambdaEvalTests :: TestTree
lambdaEvalTests = testGroup "Lambda Evaluation Tests"
  [ testCase "Lambda Identity Function" $ do
      let input = "id = (\\x : x)\nid t"
      runTricu input @?= "Leaf"
  , testCase "Lambda Constant Function (K combinator)" $ do
      let input = "k = (\\x y : x)\nk t (t t)"
      runTricu input @?= "Leaf"
  , testCase "Lambda Application with Variable" $ do
      let input = "id = (\\x : x)\nval = t t\nid val"
      runTricu input @?= "Stem Leaf"
  , testCase "Lambda Application with Multiple Arguments" $ do
      let input = "apply = (\\f x y : f x y)\nk = (\\a b : a)\napply k t (t t)"
      runTricu input @?= "Leaf"
   , testCase "Nested Lambda Application" $ do
      let input = "apply = (\\f x y : f x y)\nid = (\\x : x)\napply (\\f x : f x) id t"
      runTricu input @?= "Leaf"
  , testCase "Lambda with a complex body" $ do
      let input = "f = (\\x : t (t x))\nf t"
      runTricu input @?= "Stem (Stem Leaf)"
  , testCase "Lambda returning a function" $ do
      let input = "f = (\\x : (\\y : x))\ng = f t\ng (t t)"
      runTricu input @?= "Leaf"
  , testCase "Lambda with Shadowing" $ do
      let input = "f = (\\x : (\\x : x))\nf t (t t)"
      runTricu input @?= "Stem Leaf"
   , testCase "Lambda returning another lambda" $ do
      let input = "k = (\\x : (\\y : x))\nk_app = k t\nk_app (t t)"
      runTricu input @?= "Leaf"
   , testCase "Lambda with free variables" $ do
      let input = "y = t t\nf = (\\x : y)\nf t"
      runTricu input @?= "Stem Leaf"
   , testCase "SKI Composition" $ do
      let input = "s = (\\x y z : x z (y z))\nk = (\\x y : x)\ni = (\\x : x)\ncomp = s k i\ncomp t (t t)"
      runTricu input @?= "Stem (Stem Leaf)"
   , testCase "Lambda with multiple parameters and application" $ do
      let input = "f = (\\a b c : t a b c)\nf t (t t) (t t t)"
      runTricu input @?= "Stem Leaf"
   , testCase "Lambda with nested application in the body" $ do
      let input = "f = (\\x : t (t (t x)))\nf t"
      runTricu input @?= "Stem (Stem (Stem Leaf))"
    , testCase "Lambda returning a function and applying it" $ do
        let input = "f = (\\x : (\\y : t x y))\ng = f t\ng (t t)"
        runTricu input @?= "Fork Leaf (Stem Leaf)"
    , testCase "Lambda applying a variable" $ do
        let input = "id = (\\x : x)\na = t t\nid a"
        runTricu input @?= "Stem Leaf"
    , testCase "Nested lambda abstractions in the same expression" $ do
        let input = "f = (\\x : (\\y : x y))\ng = (\\z : z)\nf g t"
        runTricu input @?= "Leaf"
  , testCase "Lambda with a string literal" $ do
        let input = "f = (\\x : x)\nf \"hello\""
        runTricu input @?= "Fork (Fork Leaf (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork Leaf (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) (Fork (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork (Stem Leaf) Leaf))))))) Leaf))))"
   , testCase "Lambda with an integer literal" $ do
        let input = "f = (\\x : x)\nf 42"
        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) (Fork Leaf (Fork (Stem Leaf) Leaf)))))"
   , testCase "Lambda with a list literal" $ do
        let input = "f = (\\x : x)\nf [t (t t)]"
        runTricu input @?= "Fork Leaf (Fork (Stem Leaf) Leaf)"
  ]

propertyTests :: TestTree
propertyTests = testGroup "Property Tests"
  [ testProperty "Lexing and parsing round-trip" $ \input ->
      case runParser tricuLexer "" input of
        Left _ -> property True
        Right tokens -> case runParser parseExpression "" tokens of
          Left _ -> property True
          Right ast -> parseSingle input === ast
  ]