Theory Code_Char

(*  Title:      HOL/Library/Code_Char.thy
    Author:     Florian Haftmann
*)

section ‹Code generation of pretty characters (and strings)›

theory Code_Char
imports Main Char_ord
begin

code_printing
  type_constructor char ⇀
    (SML) "char"
    and (OCaml) "char"
    and (Haskell) "Prelude.Char"
    and (Scala) "Char"

setup ‹
  fold String_Code.add_literal_char ["SML", "OCaml", "Haskell", "Scala"] 
  #> String_Code.add_literal_list_string "Haskell"
›

code_printing
  constant integer_of_char ⇀
    (SML) "!(IntInf.fromInt o Char.ord)"
    and (OCaml) "Big'_int.big'_int'_of'_int (Char.code _)"
    and (Haskell) "Prelude.toInteger (Prelude.fromEnum (_ :: Prelude.Char))"
    and (Scala) "BigInt(_.toInt)"
| constant char_of_integer ⇀
    (SML) "!(Char.chr o IntInf.toInt)"
    and (OCaml) "Char.chr (Big'_int.int'_of'_big'_int _)"
    and (Haskell) "!(let chr k | (0 <= k && k < 256) = Prelude.toEnum k :: Prelude.Char in chr . Prelude.fromInteger)"
    and (Scala) "!((k: BigInt) => if (BigInt(0) <= k && k < BigInt(256)) k.charValue else error(\"character value out of range\"))"
| class_instance char :: equal ⇀
    (Haskell) -
| constant "HOL.equal :: char ⇒ char ⇒ bool" ⇀
    (SML) "!((_ : char) = _)"
    and (OCaml) "!((_ : char) = _)"
    and (Haskell) infix 4 "=="
    and (Scala) infixl 5 "=="
| constant "Code_Evaluation.term_of :: char ⇒ term" ⇀
    (Eval) "HOLogic.mk'_char/ (IntInf.fromInt/ (Char.ord/ _))"

code_reserved SML
  char

code_reserved OCaml
  char

code_reserved Scala
  char

code_reserved SML String

code_printing
  constant String.implode ⇀
    (SML) "String.implode"
    and (OCaml) "!(let l = _ in let res = String.create (List.length l) in let rec imp i = function | [] -> res | c :: l -> String.set res i c; imp (i + 1) l in imp 0 l)"
    and (Haskell) "_"
    and (Scala) "!(\"\" ++/ _)"
| constant String.explode ⇀
    (SML) "String.explode"
    and (OCaml) "!(let s = _ in let rec exp i l = if i < 0 then l else exp (i - 1) (String.get s i :: l) in exp (String.length s - 1) [])"
    and (Haskell) "_"
    and (Scala) "!(_.toList)"

code_printing
  constant "Orderings.less_eq :: char ⇒ char ⇒ bool" ⇀
    (SML) "!((_ : char) <= _)"
    and (OCaml) "!((_ : char) <= _)"
    and (Haskell) infix 4 "<="
    and (Scala) infixl 4 "<="
    and (Eval) infixl 6 "<="
| constant "Orderings.less :: char ⇒ char ⇒ bool" ⇀
    (SML) "!((_ : char) < _)"
    and (OCaml) "!((_ : char) < _)"
    and (Haskell) infix 4 "<"
    and (Scala) infixl 4 "<"
    and (Eval) infixl 6 "<"
|  constant "Orderings.less_eq :: String.literal ⇒ String.literal ⇒ bool" ⇀
    (SML) "!((_ : string) <= _)"
    and (OCaml) "!((_ : string) <= _)"
    ― ‹Order operations for @{typ String.literal} work in Haskell only 
          if no type class instance needs to be generated, because String = [Char] in Haskell
          and @{typ "char list"} need not have the same order as @{typ String.literal}.›
    and (Haskell) infix 4 "<="
    and (Scala) infixl 4 "<="
    and (Eval) infixl 6 "<="
| constant "Orderings.less :: String.literal ⇒ String.literal ⇒ bool" ⇀
    (SML) "!((_ : string) < _)"
    and (OCaml) "!((_ : string) < _)"
    and (Haskell) infix 4 "<"
    and (Scala) infixl 4 "<"
    and (Eval) infixl 6 "<"

end