(* Title: Pure/ML/ml_syntax.ML
Author: Makarius
Basic ML syntax operations.
*)
signature ML_SYNTAX =
sig
val reserved_names: string list
val reserved: Name.context
val is_reserved: string -> bool
val is_identifier: string -> bool
val atomic: string -> string
val print_int: int -> string
val print_pair: ('a -> string) -> ('b -> string) -> 'a * 'b -> string
val print_list: ('a -> string) -> 'a list -> string
val print_option: ('a -> string) -> 'a option -> string
val print_char: string -> string
val print_string: string -> string
val print_strings: string list -> string
val print_properties: Properties.T -> string
val print_position: Position.T -> string
val make_binding: string * Position.T -> string
val print_indexname: indexname -> string
val print_class: class -> string
val print_sort: sort -> string
val print_typ: typ -> string
val print_term: term -> string
end;
structure ML_Syntax: ML_SYNTAX =
struct
(* reserved words *)
val reserved_names = filter Syntax.is_ascii_identifier ML_Lex.keywords;
val reserved = Name.make_context reserved_names;
val is_reserved = Name.is_declared reserved;
(* identifiers *)
fun is_identifier name =
not (is_reserved name) andalso Syntax.is_ascii_identifier name;
(* literal output -- unformatted *)
val atomic = enclose "(" ")";
val print_int = Int.toString;
fun print_pair f1 f2 (x, y) = "(" ^ f1 x ^ ", " ^ f2 y ^ ")";
fun print_list f = enclose "[" "]" o commas o map f;
fun print_option f NONE = "NONE"
| print_option f (SOME x) = "SOME (" ^ f x ^ ")";
fun print_char s =
if not (Symbol.is_char s) then s
else if s = "\"" then "\\\""
else if s = "\\" then "\\\\"
else
let val c = ord s in
if c < 32 then "\\^" ^ chr (c + ord "@")
else if c < 127 then s
else "\\" ^ string_of_int c
end;
val print_string = quote o implode o map print_char o Symbol.explode;
val print_strings = print_list print_string;
val print_properties = print_list (print_pair print_string print_string);
fun print_position pos = "Position.of_properties " ^ print_properties (Position.properties_of pos);
fun make_binding (name, pos) = "Binding.make " ^ print_pair print_string print_position (name, pos);
val print_indexname = print_pair print_string print_int;
val print_class = print_string;
val print_sort = print_list print_class;
fun print_typ (Type arg) = "Type " ^ print_pair print_string (print_list print_typ) arg
| print_typ (TFree arg) = "TFree " ^ print_pair print_string print_sort arg
| print_typ (TVar arg) = "TVar " ^ print_pair print_indexname print_sort arg;
fun print_term (Const arg) = "Const " ^ print_pair print_string print_typ arg
| print_term (Free arg) = "Free " ^ print_pair print_string print_typ arg
| print_term (Var arg) = "Var " ^ print_pair print_indexname print_typ arg
| print_term (Bound i) = "Bound " ^ print_int i
| print_term (Abs (s, T, t)) =
"Abs (" ^ print_string s ^ ", " ^ print_typ T ^ ", " ^ print_term t ^ ")"
| print_term (t1 $ t2) = atomic (print_term t1) ^ " $ " ^ atomic (print_term t2);
end;