From e36e490a30fe7e08e8064445d6822d9b0c31a4cc Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Tue, 30 Mar 2021 13:59:27 +0800
Subject: [PATCH] Support back-tick at EOL for literal strings.

---
 src/parser.rs   |  4 ++--
 src/token.rs    | 37 +++++++++++++++++++++++++++++--------
 tests/string.rs | 12 ++++++++++++
 3 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/src/parser.rs b/src/parser.rs
index 49c1d57d..4460539d 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -715,13 +715,13 @@ fn parse_map_literal(
                 return Err(PERR::Reserved(s).into_err(pos));
             }
             (Token::LexError(err), pos) => return Err(err.into_err(pos)),
-            (_, pos) if map.is_empty() => {
+            (Token::EOF, pos) => {
                 return Err(
                     PERR::MissingToken(Token::RightBrace.into(), MISSING_RBRACE.into())
                         .into_err(pos),
                 );
             }
-            (Token::EOF, pos) => {
+            (_, pos) if map.is_empty() => {
                 return Err(
                     PERR::MissingToken(Token::RightBrace.into(), MISSING_RBRACE.into())
                         .into_err(pos),
diff --git a/src/token.rs b/src/token.rs
index c5498416..0aea77b5 100644
--- a/src/token.rs
+++ b/src/token.rs
@@ -1294,15 +1294,36 @@ fn get_next_token_inner(
                 return get_identifier(stream, pos, start_pos, c);
             }
 
-            // " or ` - string literal
-            ('"', _) | ('`', _) => {
-                let multi_line = c == '`';
+            // " - string literal
+            ('"', _) => {
+                return parse_string_literal(stream, state, pos, c, true, false).map_or_else(
+                    |err| Some((Token::LexError(err.0), err.1)),
+                    |out| Some((Token::StringConstant(out), start_pos)),
+                );
+            }
+            // ` - string literal
+            ('`', _) => {
+                // Start from the next line if ` at the end of line
+                match stream.peek_next() {
+                    // `\r - start from next line
+                    Some('\r') => {
+                        eat_next(stream, pos);
+                        // `\r\n
+                        if stream.peek_next().map(|ch| ch == '\n').unwrap_or(false) {
+                            eat_next(stream, pos);
+                        }
+                    }
+                    // `\n - start from next line
+                    Some('\n') => {
+                        eat_next(stream, pos);
+                    }
+                    _ => (),
+                }
 
-                return parse_string_literal(stream, state, pos, c, !multi_line, multi_line)
-                    .map_or_else(
-                        |err| Some((Token::LexError(err.0), err.1)),
-                        |out| Some((Token::StringConstant(out), start_pos)),
-                    );
+                return parse_string_literal(stream, state, pos, c, false, true).map_or_else(
+                    |err| Some((Token::LexError(err.0), err.1)),
+                    |out| Some((Token::StringConstant(out), start_pos)),
+                );
             }
 
             // ' - character literal
diff --git a/tests/string.rs b/tests/string.rs
index d6885a34..2e2d74a7 100644
--- a/tests/string.rs
+++ b/tests/string.rs
@@ -8,6 +8,10 @@ fn test_string() -> Result<(), Box<EvalAltResult>> {
         engine.eval::<String>(r#""Test string: \u2764""#)?,
         "Test string: ❤"
     );
+    assert_eq!(
+        engine.eval::<String>("\"Test\rstring: \\u2764\"")?,
+        "Test\rstring: ❤"
+    );
     assert_eq!(
         engine.eval::<String>("   \"Test string: \\u2764\\\n     hello, world!\"")?,
         "Test string: ❤ hello, world!"
@@ -16,6 +20,14 @@ fn test_string() -> Result<(), Box<EvalAltResult>> {
         engine.eval::<String>("     `Test string: \\u2764\nhello,\\nworld!`")?,
         "Test string: \\u2764\nhello,\\nworld!"
     );
+    assert_eq!(
+        engine.eval::<String>("     `\nTest string: \\u2764\nhello,\\nworld!`")?,
+        "Test string: \\u2764\nhello,\\nworld!"
+    );
+    assert_eq!(
+        engine.eval::<String>("     `\r\nTest string: \\u2764\nhello,\\nworld!`")?,
+        "Test string: \\u2764\nhello,\\nworld!"
+    );
     assert_eq!(
         engine.eval::<String>(r#""Test string: \x58""#)?,
         "Test string: X"