(* Title: Pure/General/symbol_pos.ML
ID: $Id$
Author: Makarius
Symbols with explicit position information.
*)
signature BASIC_SYMBOL_POS =
sig
type T = Symbol.symbol * Position.T
val symbol: T -> Symbol.symbol
val $$$ : Symbol.symbol -> T list -> T list * T list
val ~$$$ : Symbol.symbol -> T list -> T list * T list
end
signature SYMBOL_POS =
sig
include BASIC_SYMBOL_POS
val content: T list -> string
val untabify_content: T list -> string
val is_eof: T -> bool
val stopper: T Scan.stopper
val !!! : string -> (T list -> 'a) -> T list -> 'a
val scan_pos: T list -> Position.T * T list
val scan_comment: (string -> (T list -> T list * T list) -> T list -> T list * T list) ->
T list -> T list * T list
val scan_comment_body: (string -> (T list -> T list * T list) -> T list -> T list * T list) ->
T list -> T list * T list
val source: Position.T -> (Symbol.symbol, 'a) Source.source ->
(T, Position.T * (Symbol.symbol, 'a) Source.source) Source.source
type text = string
val implode: T list -> text
val range: T list -> Position.range
val implode_range: Position.T -> Position.T -> T list -> text * Position.range
val explode: text * Position.T -> T list
end;
structure SymbolPos: SYMBOL_POS =
struct
(* type T *)
type T = Symbol.symbol * Position.T;
fun symbol ((s, _): T) = s;
(* content *)
val content = implode o map symbol;
val tab_width = (8: int);
fun untabify ("\t", pos) =
(case Position.column_of pos of
SOME n => Symbol.spaces (tab_width - ((n - 1) mod tab_width))
| NONE => Symbol.space)
| untabify (s, _) = s;
val untabify_content = implode o map untabify;
(* stopper *)
fun mk_eof pos = (Symbol.eof, pos);
val eof = mk_eof Position.none;
val is_eof = Symbol.is_eof o symbol;
val stopper =
Scan.stopper (fn [] => eof | inp => mk_eof (List.last inp |-> Position.advance)) is_eof;
(* basic scanners *)
fun !!! text scan =
let
fun get_pos [] = " (past end-of-text!)"
| get_pos ((_, pos) :: _) = Position.str_of pos;
fun err (syms, msg) =
text ^ get_pos syms ^ " at " ^ Symbol.beginning 10 (map symbol syms) ^
(case msg of NONE => "" | SOME s => "\n" ^ s);
in Scan.!! err scan end;
fun $$$ s = Scan.one (fn x => symbol x = s) >> single;
fun ~$$$ s = Scan.one (fn x => symbol x <> s) >> single;
val scan_pos = Scan.ahead (Scan.one (K true)) >> (fn (_, pos): T => pos);
(* ML-style comments *)
local
val scan_cmt =
Scan.depend (fn (d: int) => $$$ "(" @@@ $$$ "*" >> pair (d + 1)) ||
Scan.depend (fn 0 => Scan.fail | d => $$$ "*" @@@ $$$ ")" >> pair (d - 1)) ||
Scan.lift ($$$ "*" --| Scan.ahead (~$$$ ")")) ||
Scan.lift (Scan.one (fn (s, _) => s <> "*" andalso Symbol.is_regular s)) >> single;
val scan_body = Scan.pass 0 (Scan.repeat scan_cmt >> flat);
in
fun scan_comment cut =
$$$ "(" @@@ $$$ "*" @@@ cut "missing end of comment" (scan_body @@@ $$$ "*" @@@ $$$ ")");
fun scan_comment_body cut =
$$$ "(" |-- $$$ "*" |-- cut "missing end of comment" (scan_body --| $$$ "*" --| $$$ ")");
end;
(* source *)
fun source pos =
Source.source' pos Symbol.stopper (Scan.bulk (Scan.depend (fn pos =>
Scan.one Symbol.not_eof >> (fn s => (Position.advance s pos, (s, pos)))))) NONE;
(* compact representation -- with Symbol.DEL padding *)
type text = string;
fun pad [] = []
| pad [(s, _)] = [s]
| pad ((s1, pos1) :: (rest as (s2, pos2) :: _)) =
let
val end_pos1 = Position.advance s1 pos1;
val d = Int.max (0, Position.distance_of end_pos1 pos2);
in s1 :: replicate d Symbol.DEL @ pad rest end;
val implode = implode o pad;
fun range (syms as (_, pos) :: _) =
let val pos' = List.last syms |-> Position.advance
in Position.range pos pos' end
| range [] = Position.no_range;
fun implode_range pos1 pos2 syms =
let val syms' = (("", pos1) :: syms @ [("", pos2)])
in (implode syms', range syms') end;
fun explode (str, pos) =
fold_map (fn s => fn p => ((s, p), (Position.advance s p)))
(Symbol.explode str) (Position.reset_range pos)
|> #1 |> filter_out (fn (s, _) => s = Symbol.DEL);
end;
structure BasicSymbolPos: BASIC_SYMBOL_POS = SymbolPos; (*not open by default*)