# Modules

Basic implementation of a module system including tests.

src/Lexer.hs

@@ -20,11 +20,11 @@ identifier = do
   first <- letterChar <|> char '_'
   rest  <- many $ letterChar 
               <|> digitChar 
-              <|> char '_' <|> char '-' <|> char '?' <|> char '!'
+              <|> 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"
+  if (name == "t" || name == "!result")
+    then fail "Keywords (`t`, `!result`) cannot be used as an identifier"
     else return (LIdentifier name)
 
 integerLiteral :: Lexer LToken
@@ -39,6 +39,22 @@ stringLiteral = do
   char '"' --"
   return (LStringLiteral content)
 
+lModule :: Lexer LToken
+lModule = do
+  _ <- string "!module"
+  space1
+  LIdentifier moduleName <- identifier
+  return (LModule moduleName)
+
+lImport :: Lexer LToken
+lImport = do
+  _ <- string "!import"
+  space1
+  LStringLiteral path <- stringLiteral
+  space1
+  LIdentifier name <- identifier
+  return (LImport path name)
+
 assign :: Lexer LToken
 assign = char '=' *> pure LAssign
 
@@ -72,28 +88,36 @@ sc = space
 tricuLexer :: Lexer [LToken]
 tricuLexer = do
   sc
+  header <- many $ do
+    tok <- choice
+      [ try lModule
+      , try lImport
+      , lnewline
+      ]
+    sc
+    pure tok
   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
-        ]
+  pure (header ++ 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