# Modules

Basic implementation of a module system including tests.

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
@@ -31,6 +32,7 @@ tests = testGroup "Tricu Tests"
   , lambdas
   , baseLibrary
   , fileEval
+  , modules
   , demos
   ]
 
@@ -70,9 +72,9 @@ lexer = testGroup "Lexer Tests"
         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"
   ]
 
 parser :: TestTree
@@ -498,22 +500,54 @@ fileEval = testGroup "File evaluation tests"
       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
+  ]
+
+
+-- All of our demo tests are also module tests
 demos :: TestTree
 demos = testGroup "Test provided demo functionality"
   [ testCase "Structural equality demo" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
-      res     <- liftIO $ evaluateFileWithContext library "./demos/equality.tri"
-      decodeResult (result res) @?= "t t"
+      res     <- liftIO $ evaluateFileResult "./demos/equality.tri"
+      decodeResult res @?= "t t"
   , testCase "Convert values back to source code demo" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
-      res     <- liftIO $ evaluateFileWithContext library "./demos/toSource.tri"
-      decodeResult (result res) @?= "\"(t (t (t t) (t t t)) (t t (t t t)))\""
+      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
-      library <- liftIO $ evaluateFile "./lib/base.tri"
-      res     <- liftIO $ evaluateFileWithContext library "./demos/size.tri"
-      decodeResult (result res) @?= "454"
+      res     <- liftIO $ evaluateFileResult "./demos/size.tri"
+      decodeResult res @?= "454"
   , testCase "Level Order Traversal demo" $ do
-      library <- liftIO $ evaluateFile "./lib/base.tri"
-      res     <- liftIO $ evaluateFileWithContext library "./demos/levelOrderTraversal.tri"
-      decodeResult (result res) @?= "\"\n1 \n2 3 \n4 5 6 7 \n8 11 10 9 12 \""
+      res     <- liftIO $ evaluateFileResult "./demos/levelOrderTraversal.tri"
+      decodeResult res @?= "\"\n1 \n2 3 \n4 5 6 7 \n8 11 10 9 12 \""
   ]

test/cycle-1.tri

@@ -0,0 +1,5 @@
+!module Cycle
+
+!import "test/cycle-2.tri" Cycle2
+
+cycle1 = t Cycle2.cycle2

test/cycle-2.tri

@@ -0,0 +1,5 @@
+!module Cycle2
+
+!import "test/cycle-1.tri" Cycle1
+
+cycle2 = t Cycle1.cycle1

test/lambda-A.tri

@@ -0,0 +1,2 @@
+!module A
+main = (\x : x) t

test/modules-1.tri

@@ -0,0 +1,5 @@
+!module Test
+
+!import "lib/base.tri" Lib
+
+main = Lib.not? t

test/modules-2.tri

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

test/multi-level-A.tri

@@ -0,0 +1,3 @@
+!module A
+!import "./test/multi-level-B.tri" B
+main = B.main

test/multi-level-B.tri

@@ -0,0 +1,3 @@
+!module B
+!import "./test/multi-level-C.tri" C
+main = C.val

test/multi-level-C.tri

@@ -0,0 +1,2 @@
+!module C
+val = t

test/namespace-A.tri

@@ -0,0 +1,3 @@
+!module A
+!import "./test/namespace-B.tri" B
+main = B.x

test/namespace-B.tri

@@ -0,0 +1,2 @@
+!module B
+x = t

test/unresolved-A.tri

@@ -0,0 +1,2 @@
+!module A
+main = undefinedVar

test/vars-A.tri

@@ -0,0 +1,7 @@
+!module A
+
+!import "./test/vars-B.tri" B
+
+!import "./test/vars-C.tri" C
+
+main = B.y (C.z)

test/vars-B.tri

@@ -0,0 +1,2 @@
+!module B
+y = \x : x

test/vars-C.tri

@@ -0,0 +1,2 @@
+!module C
+z = t