(* Title: HOL/ex/Multiquote.thy
ID: $Id$
Author: Markus Wenzel, TU Muenchen
*)
header {* Multiple nested quotations and anti-quotations *}
theory Multiquote imports Main begin
text {*
Multiple nested quotations and anti-quotations -- basically a
generalized version of de-Bruijn representation.
*}
syntax
"_quote" :: "'b => ('a => 'b)" ("\<guillemotleft>_\<guillemotright>" [0] 1000)
"_antiquote" :: "('a => 'b) => 'b" ("\<acute>_" [1000] 1000)
parse_translation {*
let
fun antiquote_tr i (Const ("_antiquote", _) $ (t as Const ("_antiquote", _) $ _)) =
skip_antiquote_tr i t
| antiquote_tr i (Const ("_antiquote", _) $ t) =
antiquote_tr i t $ Bound i
| antiquote_tr i (t $ u) = antiquote_tr i t $ antiquote_tr i u
| antiquote_tr i (Abs (x, T, t)) = Abs (x, T, antiquote_tr (i + 1) t)
| antiquote_tr _ a = a
and skip_antiquote_tr i ((c as Const ("_antiquote", _)) $ t) =
c $ skip_antiquote_tr i t
| skip_antiquote_tr i t = antiquote_tr i t;
fun quote_tr [t] = Abs ("s", dummyT, antiquote_tr 0 (Term.incr_boundvars 1 t))
| quote_tr ts = raise TERM ("quote_tr", ts);
in [("_quote", quote_tr)] end
*}
text {* basic examples *}
term "\<guillemotleft>a + b + c\<guillemotright>"
term "\<guillemotleft>a + b + c + \<acute>x + \<acute>y + 1\<guillemotright>"
term "\<guillemotleft>\<acute>(f w) + \<acute>x\<guillemotright>"
term "\<guillemotleft>f \<acute>x \<acute>y z\<guillemotright>"
text {* advanced examples *}
term "\<guillemotleft>\<guillemotleft>\<acute>\<acute>x + \<acute>y\<guillemotright>\<guillemotright>"
term "\<guillemotleft>\<guillemotleft>\<acute>\<acute>x + \<acute>y\<guillemotright> o \<acute>f\<guillemotright>"
term "\<guillemotleft>\<acute>(f o \<acute>g)\<guillemotright>"
term "\<guillemotleft>\<guillemotleft>\<acute>\<acute>(f o \<acute>g)\<guillemotright>\<guillemotright>"
end