support for multi-line defines

Language/SystemVerilog/Parser/Preprocess.hs

@@ -48,18 +48,21 @@ preprocess env file content = unlines $ pp True [] env $ lines $ uncomment file
   where
   pp :: Bool -> [Bool] -> [(String, String)] -> [String] -> [String]
   pp _ _ _ [] = []
-  pp on stack env (a : rest) = case words a of
-    "`define" : name : value -> "" : pp on stack (if on then (name, ppLine env $ unwords value) : env else env) rest
-    "`ifdef"  : name : _     -> "" : pp (on && (elem    name $ fst $ unzip env)) (on : stack) env rest
-    "`ifndef" : name : _     -> "" : pp (on && (notElem name $ fst $ unzip env)) (on : stack) env rest
-    "`else" : _
-      | not $ null stack     -> "" : pp (head stack && not on) stack env rest
-      | otherwise            -> error $ "`else  without associated `ifdef/`ifndef: " ++ file
-    "`endif" : _
-      | not $ null stack     -> "" : pp (head stack) (tail stack) env rest
-      | otherwise            -> error $ "`endif  without associated `ifdef/`ifndef: " ++ file
-    "`default_nettype" : _   -> "" : pp on stack env rest
-    _                        -> (if on then ppLine env a else "") : pp on stack env rest
+  pp on stack env (a : rest) =
+    if a /= "" && last a == '\\' && head a == '`'
+    then pp on stack env $ ((init a) ++ " " ++ (head rest)) : (tail rest)
+    else case words a of
+      "`define" : name : value -> "" : pp on stack (if on then (name, ppLine env $ unwords value) : env else env) rest
+      "`ifdef"  : name : _     -> "" : pp (on && (elem    name $ fst $ unzip env)) (on : stack) env rest
+      "`ifndef" : name : _     -> "" : pp (on && (notElem name $ fst $ unzip env)) (on : stack) env rest
+      "`else" : _
+        | not $ null stack     -> "" : pp (head stack && not on) stack env rest
+        | otherwise            -> error $ "`else  without associated `ifdef/`ifndef: " ++ file
+      "`endif" : _
+        | not $ null stack     -> "" : pp (head stack) (tail stack) env rest
+        | otherwise            -> error $ "`endif  without associated `ifdef/`ifndef: " ++ file
+      "`default_nettype" : _   -> "" : pp on stack env rest
+      _                        -> (if on then ppLine env a else "") : pp on stack env rest
 
 ppLine :: [(String, String)] -> String -> String
 ppLine _ "" = ""