(* Title: HOL/ex/Antiquote.thy
Author: Markus Wenzel, TU Muenchen
*)
header {* Antiquotations *}
theory Antiquote
imports Main
begin
text {*
A simple example on quote / antiquote in higher-order abstract
syntax.
*}
syntax
"_Expr" :: "'a => 'a" ("EXPR _" [1000] 999)
definition
var :: "'a => ('a => nat) => nat" ("VAR _" [1000] 999)
where "var x env = env x"
definition
Expr :: "(('a => nat) => nat) => ('a => nat) => nat"
where "Expr exp env = exp env"
parse_translation {*
[Syntax_Trans.quote_antiquote_tr
@{syntax_const "_Expr"} @{const_syntax var} @{const_syntax Expr}]
*}
print_translation {*
[Syntax_Trans.quote_antiquote_tr'
@{syntax_const "_Expr"} @{const_syntax var} @{const_syntax Expr}]
*}
term "EXPR (a + b + c)"
term "EXPR (a + b + c + VAR x + VAR y + 1)"
term "EXPR (VAR (f w) + VAR x)"
term "Expr (\<lambda>env. env x)" -- {* improper *}
term "Expr (\<lambda>env. f env)"
term "Expr (\<lambda>env. f env + env x)" -- {* improper *}
term "Expr (\<lambda>env. f env y z)"
term "Expr (\<lambda>env. f env + g y env)"
term "Expr (\<lambda>env. f env + g env y + h a env z)"
end