From 2f07d890433bebedc136037ad9cce2eed25b0437 Mon Sep 17 00:00:00 2001
From: Mirek Kratochvil <exa.exa@gmail.com>
Date: Wed, 14 Dec 2022 22:56:47 +0100
Subject: 10h vacuum cleaner sound

---
 app/Parser.hs | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

(limited to 'app/Parser.hs')

diff --git a/app/Parser.hs b/app/Parser.hs
index 864cdc5..acc8104 100644
--- a/app/Parser.hs
+++ b/app/Parser.hs
@@ -172,29 +172,27 @@ literal = Literal . unTok <$> free (satisfy isNormalTok <* notFollowedBy lParen)
 
 call = do
   fn <- unTok <$> satisfy isNormalTok -- not free
-  Seq inner <- free parens
-  return $ Call fn $ splitOn [Literal ","] inner
+  (Call fn [] <$ try emptyParens) <|> do
+    Seq inner <- free parens
+    return $ Call fn $ splitOn [Literal ","] inner
 
 parens = Seq <$> (free lParen *> some seqItem <* free rParen)
 
+emptyParens = Literal "()" <$ (free lParen >> free rParen)
+
 list = do
   free lBracket
-  choice
-    [ List [] Nothing <$ free rBracket
-    , do items <- splitOn [Literal ","] <$> some seqItem
-         choice
-           [ List items Nothing <$ free rBracket
-           , List items . Just <$>
-             (free listTail *> some seqItem <* free rBracket)
-           ]
-    ]
+  (List [] Nothing <$ free rBracket) <|> do
+    items <- splitOn [Literal ","] <$> some seqItem
+    (List items Nothing <$ free rBracket) <|>
+      (List items . Just <$> (free listTail *> some seqItem <* free rBracket))
 
-seqItem = choice [try call, literal, parens, list]
+seqItem = choice [try call, literal, try emptyParens, parens, list]
 
 simpleTok :: String -> Parser ()
 simpleTok s = void $ single (Tok s)
 
-comma = simpleTok "."
+period = simpleTok "."
 
 lParen = simpleTok "("
 
@@ -207,7 +205,7 @@ listTail = simpleTok "|"
 rBracket = simpleTok "]"
 
 clause :: Parser PAST
-clause = Seq <$> some (free seqItem) <* free comma
+clause = Seq <$> some (free seqItem) <* free period
 
 parsePrlg :: Parser [PAST]
 parsePrlg = ws *> many clause <* eof
-- 
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