1.3 String literals

The raw byte sequence within a string literal is escaped according to the C++ standard. In particular, this means that UTF-8 encoded strings are supported, however they are not tested for invalid byte sequences. A print or reject statement should properly display Unicode characters if your terminal supports the encoding used in the input. In other words, Stan simply preserves any string of bytes between two double quotes (") when passing to C++. On compliant terminals, this allows the use of glyphs and other characters from encodings such as UTF-8 that fall outside the ASCII-compatible range.

ASCII is the recommended encoding for maximum portability, because it encodes the ASCII characters (Unicode code points 0–127) using the same sequence of bytes as the UTF-8 encoding of Unicode and common ISO-8859 extensions of Latin.