From 039fffb33964f29258716710dee996fda959742e Mon Sep 17 00:00:00 2001
From: Mark <markjordanthom@gmail.com>
Date: Tue, 27 Jun 2023 16:39:10 -0600
Subject: [PATCH] better detect syntax errors in lexer.rs (#1771)

---
 src/lib/charsio.pl  | 1 +
 src/parser/lexer.rs | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/lib/charsio.pl b/src/lib/charsio.pl
index 1fc120f0..99b5c281 100644
--- a/src/lib/charsio.pl
+++ b/src/lib/charsio.pl
@@ -193,6 +193,7 @@ get_single_char(C) :-
 % ```
 read_from_chars(Chars, Term) :-
     must_be(chars, Chars),
+    must_be(var, Term),
     '$read_term_from_chars'(Chars, Term).
 
 %% write_term_to_chars(+Term, +Options, -Chars).
diff --git a/src/parser/lexer.rs b/src/parser/lexer.rs
index 9aeacd82..236585d9 100644
--- a/src/parser/lexer.rs
+++ b/src/parser/lexer.rs
@@ -859,7 +859,13 @@ impl<'a, R: CharRead> Lexer<'a, R> {
 
                     self.get_single_quoted_char()
                         .map(|c| Token::Literal(Literal::Fixnum(Fixnum::build_with(c as i64))))
-                        .or_else(|_| {
+                        .or_else(|err| {
+                            match err {
+                                ParserError::UnexpectedChar('\'', ..) => {
+                                }
+                                err => return Err(err),
+                            }
+
                             self.return_char(c);
 
                             i64::from_str_radix(&token, 10)
-- 
2.54.0