From ca9b97f14e4b55902ddac6f909cc2ad732ae16ec Mon Sep 17 00:00:00 2001
From: Nikolay Yakimov <root@livid.pp.ru>
Date: Wed, 3 Jun 2020 18:28:10 +0300
Subject: [PATCH] Make lexer FA graph output optional

---
 Main.hs            | 9 ++++++---
 README.md          | 2 ++
 lib/Lexer/Build.hs | 8 +++++---
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/Main.hs b/Main.hs
index 6c7ed66..5bc71eb 100644
--- a/Main.hs
+++ b/Main.hs
@@ -21,11 +21,11 @@ import qualified Options.Applicative as OA
 import Data.Version
 import Paths_alpaca_parser_generator
 
-type MainProgram = Text -> FilePath -> FilePath -> IO ()
+type MainProgram = Bool -> Text -> FilePath -> FilePath -> IO ()
 
 runProgram :: (LexerWriter lang, ParserWriter parser lang) =>
               Proxy lang -> Proxy parser -> MainProgram
-runProgram lang parserMethod parserName baseFileName inputFile = do
+runProgram lang parserMethod debugLexer parserName baseFileName inputFile = do
   input <- T.readFile inputFile
   let (lexicRaw, grammarLines) = second (drop 1) . break (=="%%") $ T.lines input
       rootdir = takeDirectory inputFile
@@ -33,7 +33,7 @@ runProgram lang parserMethod parserName baseFileName inputFile = do
       lexic = filter (not . T.null) lexicRaw
   setCurrentDirectory rootdir
   runInIO $ do
-    writeFiles =<< makeLexer lang lexic
+    writeFiles =<< makeLexer lang debugLexer lexic
     wrap parserName $ makeParser lang parserMethod ParserOptions{
         parserOptionsName = parserName
       , parserOptionsBaseFileName = baseFileName
@@ -88,6 +88,9 @@ parser = (option (enumReader langTbl)
       <> help "Parser method, default lalr"
       <> metavar (intercalate "|" (concatMap fst parsTbl))
       <> value (ParserProxy lalrParser)))
+  <*> switch
+       ( long "debug-lexer"
+      <> help "Output lexer finite automata graphs in GraphViz format")
   <*> strOption
        ( short 'n'
       <> long "name"
diff --git a/README.md b/README.md
index 72296b2..0ec776d 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,8 @@ Available options:
                            Target language, default cpp
   -p,--parser recursive|rec|ll1|lr0|lr1|slr|lalr
                            Parser method, default lalr
+  --debug-lexer            Output lexer finite automata graphs in GraphViz
+                           format
   -n,--name NAME           Parser class name, default "Parser"
   -b,--basename FILENAME   Parser output file base name, default "parser"
   GRAMMARFILE              Grammar input file
diff --git a/lib/Lexer/Build.hs b/lib/Lexer/Build.hs
index 38e6d9c..5a02df2 100644
--- a/lib/Lexer/Build.hs
+++ b/lib/Lexer/Build.hs
@@ -24,12 +24,14 @@ import Lexer.Types
 import Data.Proxy
 
 makeLexer :: (LexerWriter lang, Monad m) => Proxy lang
-           -> [Text] -> MyMonadT m [(FilePath,Text)]
-makeLexer lang input = do
+          -> Bool -> [Text] -> MyMonadT m [(FilePath,Text)]
+makeLexer lang outputDebug input = do
   defs <- liftEither . left T.lines $ mapM (fmap regex . scanLine) input
   let nfa = evalState (buildNFA defs) 0
       dfa = simplifyDFA . nfaToDFA $ nfa
-      debug = (("nfa.gv", nfaToGraphviz nfa) :) . (("dfa.gv", dfaToGraphviz dfa) :)
+      debug = if outputDebug
+        then (("nfa.gv", nfaToGraphviz nfa) :) . (("dfa.gv", dfaToGraphviz dfa) :)
+        else id
       stList = map (second (second M.toList)) $ IM.toList dfa
 
   accSt <- catMaybes <$> mapM (\(f, (s, _)) -> fmap (f,) <$> isSingle f s) stList