Allow escaped quotation marks in BLT parser

src/parser/blt.rs

@@ -255,9 +255,27 @@ impl<N: Number, I: Iterator<Item=char>> BLTParser<N, I> {
 		if self.lookahead() == '"' {
 			self.accept(); // Opening quotation mark
 			let mut result = String::new();
+			
+			loop {
+				// Read string contents
+				if self.lookahead() == '"' {
+					break;
+				} else if self.lookahead() == '\\' {
+					// Escape sequence
+					self.accept();
+					if self.lookahead() == '"' || self.lookahead() == '\\' {
+						result.push(self.accept());
+					} else {
+						return Err(ParseError::Unexpected(self.line_no, self.col_no, self.lookahead()));
+					}
+				} else {
+					result.push(self.accept());
+				}
+			}
+			
 			while self.lookahead() != '"' {
 				// TODO: BufRead::read_until ?
-				result.push(self.accept());
+				
 			}
 			self.accept(); // Closing quotation mark
 			if !self.eof() {