Experimental parser: Fix multi-line strings.

src/lexer/lexer.re

Index: src/lexer/lexer.re
diff --git a/src/lexer/lexer.re b/src/lexer/lexer.re
index 6a48880c550a2e705bd7ce567578b733db889218..942a9ceddeff1160bed2f7719f466168da3d019a 100644
--- a/src/lexer/lexer.re
+++ b/src/lexer/lexer.re
@@ -322,12 +322,16 @@ start_:
 
     <DoubleQuoteString> "\\\""  { goto yy0; }
     <DoubleQuoteString> '"'     { PUSH_TOKEN(Token::STRING);}
+    <DoubleQuoteString> "\\" "\n" "\r"? { goto yy0; }
+    <DoubleQuoteString> "\\" "\r" "\n"? { goto yy0; }
     <DoubleQuoteString> line_terminator { TERMINATE_ILLEGAL(); }
     <DoubleQuoteString> eof     { TERMINATE_ILLEGAL(); }
     <DoubleQuoteString> any     { goto yy0; }
 
     <SingleQuoteString> "\\'"   { goto yy0; }
     <SingleQuoteString> "'"     { PUSH_TOKEN(Token::STRING);}
+    <SingleQuoteString> "\\" "\n" "\r"? { goto yy0; }
+    <SingleQuoteString> "\\" "\r" "\n"? { goto yy0; }
     <SingleQuoteString> line_terminator { TERMINATE_ILLEGAL(); }
     <SingleQuoteString> eof     { TERMINATE_ILLEGAL(); }
     <SingleQuoteString> any     { goto yy0; }