From 3686f4c33ea82e1cb04895e85ad001dec69eb071 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Sat, 11 May 2024 11:41:27 +0200
Subject: [PATCH] Avoid re-parsing if delimiter reaches the end of the string
 (#64)

---
 lib/makeup/lexer/combinators.ex | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/makeup/lexer/combinators.ex b/lib/makeup/lexer/combinators.ex
index fc094fe..2961b07 100644
--- a/lib/makeup/lexer/combinators.ex
+++ b/lib/makeup/lexer/combinators.ex
@@ -120,6 +120,9 @@ defmodule Makeup.Lexer.Combinators do
   Matches a given combinator, repeated 0 or more times, surrounded by left and right delimiters.
 
   Delimiters can be combinators or literal strings (either both combinators or both literal strings).
+
+  It also succeeds if we get to the end of string and the closing delimiter is missing,
+  to avoid parsing the program multiple times in case of mismatched delimeters or invalid programs.
   """
   def many_surrounded_by(combinator, left, right) when is_binary(left) and is_binary(right) do
     token(left, :punctuation)
@@ -129,7 +132,7 @@ defmodule Makeup.Lexer.Combinators do
         |> concat(combinator)
       )
     )
-    |> concat(token(right, :punctuation))
+    |> choice([token(right, :punctuation), eos()])
   end
 
   def many_surrounded_by(combinator, left, right) do
@@ -140,12 +143,15 @@ defmodule Makeup.Lexer.Combinators do
         |> concat(combinator)
       )
     )
-    |> concat(right)
+    |> choice([right, eos()])
   end
 
   @doc """
   Matches a given combinator, repeated 0 or more times, surrounded by left and right delimiters,
   and wraps the `right` and `left` delimiters into a token of the given `ttype`.
+
+  It also succeeds if we get to the end of string and the closing delimiter is missing,
+  to avoid parsing the program multiple times in case of mismatched delimeters or invalid programs.
   """
   def many_surrounded_by(combinator, left, right, ttype) do
     token(left, ttype)
@@ -155,7 +161,7 @@ defmodule Makeup.Lexer.Combinators do
         |> concat(combinator)
       )
     )
-    |> concat(token(right, ttype))
+    |> choice([token(right, ttype), eos()])
   end
 
   @doc false