section \<open>Concrete Syntax\<close>
theory Quote_Antiquote imports Main begin
syntax
  "_quote"     :: "'b \<Rightarrow> ('a \<Rightarrow> 'b)"                ("(\<guillemotleft>_\<guillemotright>)" [0] 1000)
  "_antiquote" :: "('a \<Rightarrow> 'b) \<Rightarrow> 'b"                ("\<acute>_" [1000] 1000)
  "_Assert"    :: "'a \<Rightarrow> 'a set"                    ("(\<lbrace>_\<rbrace>)" [0] 1000)
translations
  "\<lbrace>b\<rbrace>" \<rightharpoonup> "CONST Collect \<guillemotleft>b\<guillemotright>"
parse_translation \<open>
  let
    fun quote_tr [t] = Syntax_Trans.quote_tr \<^syntax_const>\<open>_antiquote\<close> t
      | quote_tr ts = raise TERM ("quote_tr", ts);
  in [(\<^syntax_const>\<open>_quote\<close>, K quote_tr)] end
\<close>
end