Java serialization (pretty print) of strings does not escape special chars

[marco-comini]

While predefined basic type String in Haskell backend serialization escapes special chars in strings (like "line1\nline2") in Java it does not (and output is "line1
line2").

[andreasabel]

This issue exists in all non-FP backends.

The Haskell backend produces the following printer for strings:

printString :: String -> Doc
printString s = doc (showChar '"' . concatS (map (mkEsc '"') s) . showChar '"')

mkEsc :: Char -> Char -> ShowS
mkEsc q = \case
  s | s == q -> showChar '\\' . showChar s
  '\\' -> showString "\\\\"
  '\n' -> showString "\\n"
  '\t' -> showString "\\t"
  s -> showChar s

The Ocaml backend produces:

let prtString (_:int) (s:string) : doc = render ("\"" ^ String.escaped s ^ "\"")

From the docs: https://v2.ocaml.org/api/String.html

escaped s is s with special characters represented by escape sequences, following the lexical conventions of OCaml.

All characters outside the US-ASCII printable range [0x20;0x7E] are escaped, as well as backslash (0x2F) and double-quote (0x22).

Java produces only this:

  private static void printQuoted(String s) { render("\"" + s + "\""); }

CPP this:

void PrintAbsyn::visitString(String s)
{
  bufAppend('\"');
  bufAppend(s);
  bufAppend('\"');
  bufAppend(' ');
}

[andreasabel]

While working on this issue, I found that two backends do not lex escape characters properly:

• Java/ANTLR does not lex escape sequences in String #451
• Ocaml backends do not lex escape sequences in Char #452

[marco-comini]

thank you