let in_scope_tag = "tag:in_scope" ;;
let out_scope_tag_prefix = "tag:out_scope:"
let out_scope_tag n = out_scope_tag_prefix ^ string_of_int n ;;
let in_scope_tag = "tag:in_scope" ;;
let out_scope_tag_prefix = "tag:out_scope:"
let out_scope_tag n = out_scope_tag_prefix ^ string_of_int n ;;