From 26b1c599379dec6148fb2b9145df534a7db5b0c2 Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Tue, 25 Jul 2023 15:32:42 +0200
Subject: [PATCH] Domain Parser: return the last point.

---
 src/DomainParser.purs | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/DomainParser.purs b/src/DomainParser.purs
index 75640e5..0c8ec43 100644
--- a/src/DomainParser.purs
+++ b/src/DomainParser.purs
@@ -34,11 +34,15 @@ domain = PC.try (string " ") <|> sub_eof
 sub_eof :: Parser String String
 sub_eof = do
   sub <- subdomain
-  PC.optional (char '.')
+  maybe_final_point <- PC.optionMaybe (char '.')
   eof
-  if S.length sub > 255
-  then fail $ "domain length is > 255 bytes (" <> show (S.length sub) <> ")"
-  else pure sub
+  let parsed_domain = did_we_parsed_the_final_point maybe_final_point sub
+  if S.length parsed_domain > 255
+  then fail $ "domain length is > 255 bytes (" <> show (S.length parsed_domain) <> ")"
+  else pure parsed_domain
+  where
+    did_we_parsed_the_final_point Nothing  sub = sub
+    did_we_parsed_the_final_point (Just _) sub = sub <> "."
 
 -- From RFC 1035: <subdomain> ::= <label> | <subdomain> "." <label>
 subdomain :: Parser String String
@@ -46,7 +50,7 @@ subdomain = do
   -- First: read a label. This is bare minimum for a subdomain.
   lab <- label
   -- Second: the rest is optional.
-  r <- PC.optionMaybe point_sub
+  r <- PC.optionMaybe (PC.try point_sub)
   case r of
     Nothing  -> pure lab
     Just sub -> pure $ lab <> sub