(* Title: ZF/Let
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1995 University of Cambridge
Let expressions -- borrowed from HOL
*)
Let = ZF +
types
letbinds letbind
consts
Let :: "['a, 'a => 'b] => 'b"
syntax
"_bind" :: "[idt, 'a] => letbind" ("(2_ =/ _)" 10)
"" :: "letbind => letbinds" ("_")
"_binds" :: "[letbind, letbinds] => letbinds" ("_;/ _")
"_Let" :: "[letbinds, 'a] => 'a" ("(let (_)/ in (_))" 10)
translations
"_Let(_binds(b, bs), e)" == "_Let(b, _Let(bs, e))"
"let x = a in e" == "Let(a, %x. e)"
defs
Let_def "Let(s, f) == f(s)"
end