Adds basic tests for modules

Basic tests for modules. Fixes for parsing multiple import statements.

README.md

@@ -10,12 +10,13 @@ tricu is the word for "tree" in Lojban: `(x1) is a tree of species/cultivar (x2)
 
 - Tree Calculus operator: `t`
 - Assignments: `x = t t`
+- Immutabile 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 : lconcat a "!") [("Hello")]`
 - Intensionality blurs the distinction between functions and data (see REPL examples)
-- Immutability
+- Simple module system for code organization
 
 ## REPL examples
 

src/Parser.hs

@@ -76,12 +76,16 @@ parseProgramM = do
   skipMany topLevelNewline
   moduleNode <- optional parseModuleM
   skipMany topLevelNewline
-  importNodes <- many parseImportM
+  importNodes <- many (do
+    node <- parseImportM
+    skipMany topLevelNewline
+    return node)
   skipMany topLevelNewline
   exprs <- sepEndBy parseOneExpression (some topLevelNewline)
   skipMany topLevelNewline
   return (maybe [] (: []) moduleNode ++ importNodes ++ exprs)
 
+
 parseModuleM :: ParserM TricuAST
 parseModuleM = do
   LModule moduleName <- satisfyM isModule

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
   ]
 
@@ -498,6 +500,42 @@ 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

test/lambda-A.tri

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