From 637daa5bda4b1d26c2d8b958e5d7fb6060de6564 Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Wed, 8 Dec 2021 10:37:37 +0100
Subject: [PATCH 1/2] remove redundant test: '\n' is a layout char.

---
 crates/prolog_parser/src/lexer.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/prolog_parser/src/lexer.rs b/crates/prolog_parser/src/lexer.rs
index 5c355705..210722c6 100644
--- a/crates/prolog_parser/src/lexer.rs
+++ b/crates/prolog_parser/src/lexer.rs
@@ -791,7 +791,7 @@ impl<'a, R: Read> Lexer<'a, R> {
             let cr = self.lookahead_char();
 
             match cr {
-                Ok(c) if layout_char!(c) || new_line_char!(c) => {
+                Ok(c) if layout_char!(c) => {
                     self.skip_char()?;
                     layout_inserted = true;
                 }

From f79b8a1ca5861ae6a7652301ed2b3faea4b0f0b4 Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Wed, 8 Dec 2021 10:42:19 +0100
Subject: [PATCH 2/2] ENHANCED: support full layout text sequence (also
 comments) in integers with underscores

Example:

    ?- X = 1_/**/2.
    %@    X = 12.

Following the comment in https://github.com/mthom/scryer-prolog/pull/1112#issuecomment-981540485
---
 crates/prolog_parser/src/lexer.rs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/crates/prolog_parser/src/lexer.rs b/crates/prolog_parser/src/lexer.rs
index 210722c6..8be50d36 100644
--- a/crates/prolog_parser/src/lexer.rs
+++ b/crates/prolog_parser/src/lexer.rs
@@ -564,11 +564,8 @@ impl<'a, R: Read> Lexer<'a, R> {
 
         if c == '_' {
             self.skip_char()?;
+            self.scan_for_layout()?;
             c = self.lookahead_char()?;
-            while layout_char!(c) {
-                self.skip_char()?;
-                c = self.lookahead_char()?;
-            }
 
             if decimal_digit_char!(c) {
                 Ok(c)