(* Title: Pure/General/antiquote.ML
Author: Makarius
Antiquotations within plain text.
*)
signature ANTIQUOTE =
sig
type antiq = Symbol_Pos.T list * {start: Position.T, stop: Position.T, range: Position.range}
datatype 'a antiquote = Text of 'a | Antiq of antiq
val is_text: 'a antiquote -> bool
val antiq_reports: antiq -> Position.report list
val antiquote_reports: ('a -> Position.report_text list) ->
'a antiquote list -> Position.report_text list
val scan_antiq: Symbol_Pos.T list -> antiq * Symbol_Pos.T list
val scan_antiquote: Symbol_Pos.T list -> Symbol_Pos.T list antiquote * Symbol_Pos.T list
val read: Symbol_Pos.T list * Position.T -> Symbol_Pos.T list antiquote list
end;
structure Antiquote: ANTIQUOTE =
struct
(* datatype antiquote *)
type antiq = Symbol_Pos.T list * {start: Position.T, stop: Position.T, range: Position.range};
datatype 'a antiquote = Text of 'a | Antiq of antiq;
fun is_text (Text _) = true
| is_text _ = false;
(* reports *)
fun antiq_reports ((_, {start, stop, range = (pos, _)}): antiq) =
[(start, Markup.antiquote), (stop, Markup.antiquote), (pos, Markup.antiquoted)];
fun antiquote_reports text =
maps (fn Text x => text x | Antiq antiq => map (rpair "") (antiq_reports antiq));
(* scan *)
open Basic_Symbol_Pos;
local
val err_prefix = "Antiquotation lexical error: ";
val scan_txt =
Scan.repeat1 ($$$ "@" --| Scan.ahead (~$$ "{") ||
Scan.many1 (fn (s, _) => s <> "@" andalso Symbol.is_regular s)) >> flat;
val scan_antiq_body =
Scan.trace (Symbol_Pos.scan_string_qq err_prefix || Symbol_Pos.scan_string_bq err_prefix) >> #2 ||
Scan.trace (Symbol_Pos.scan_cartouche err_prefix) >> #2 ||
Scan.one (fn (s, _) => s <> "}" andalso Symbol.is_regular s) >> single;
in
val scan_antiq =
Symbol_Pos.scan_pos -- ($$ "@" |-- $$ "{" |-- Symbol_Pos.scan_pos --
Symbol_Pos.!!! (fn () => err_prefix ^ "missing closing brace")
(Scan.repeat scan_antiq_body -- Symbol_Pos.scan_pos -- ($$ "}" |-- Symbol_Pos.scan_pos)))
>> (fn (pos1, (pos2, ((body, pos3), pos4))) =>
(flat body,
{start = Position.set_range (pos1, pos2),
stop = Position.set_range (pos3, pos4),
range = Position.range pos1 pos4}));
val scan_antiquote = scan_antiq >> Antiq || scan_txt >> Text;
end;
(* read *)
fun read (syms, pos) =
(case Scan.read Symbol_Pos.stopper (Scan.repeat scan_antiquote) syms of
SOME xs => (Position.reports_text (antiquote_reports (K []) xs); xs)
| NONE => error ("Malformed quotation/antiquotation source" ^ Position.here pos));
end;