From de249084d343a1503400112580a28fe5b038d4f6 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Wed, 23 Feb 2022 20:42:03 +0100
Subject: Cool trees

---
 src/Fun/Parser.hs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

(limited to 'src/Fun/Parser.hs')

diff --git a/src/Fun/Parser.hs b/src/Fun/Parser.hs
index 4519e2f..8042caa 100644
--- a/src/Fun/Parser.hs
+++ b/src/Fun/Parser.hs
@@ -2,8 +2,9 @@ module Fun.Parser where
 
 import           Fun.Tree
 
+data Trace = StringTrace String | OrTrace [Trace] [Trace]
 data State = State
-  { trace :: [String]
+  { trace :: [Trace]
   , line  :: Maybe String
   }
 type Parser a = String -> Either State (a, String)
@@ -33,7 +34,7 @@ isAlpha c = elem c $ lowerAlpha ++ upperAlpha
 ----
 
 char :: Parser Char
-char []       = Left $ State ["char"] Nothing
+char []       = Left $ State [StringTrace "char"] Nothing
 char (x : xs) = Right (x, xs)
 
 digit :: Parser Char
@@ -86,7 +87,7 @@ result :: a -> Parser a
 result a cs = Right (a, cs)
 
 invalid :: a -> Parser a
-invalid a cs = Left $ State ["<unknown>"] $ Just "Invalid"
+invalid a cs = Left $ State [StringTrace "<unknown>"] $ Just "Invalid"
 
 iter :: Parser Char -> Parser String
 iter m = (iterS m) <=> (/= "") <?> "multiple chars"
@@ -166,7 +167,7 @@ infixl 3 <|>
     Left (State t' l) -> case (t, t') of
       (t , []) -> Left (State t l)
       ([], t') -> Left (State t' l)
-      (t , t') -> Left (State (t ++ ["<OR>"] ++ t') l)
+      (t , t') -> Left (State [OrTrace t t'] l)
     Right (result, cs) -> Right (result, cs)
   result -> result
 
@@ -174,7 +175,7 @@ infixl 3 <|>
 infix 0 <?>
 (<?>) :: Parser a -> String -> Parser a
 (parser <?> string) input = case parser input of
-  Left  (State t l) -> Left $ State ([string] ++ t) l
+  Left  (State t l) -> Left $ State ([StringTrace string] ++ t) l
   Right a           -> Right a
 
 ----
-- 
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