Formal comment #93 (defect)

Protocol environment
Reported by:	Andre van Tonder

Component:	records
Version:	5.91

Summary: 

The environment for the protocol is not well specified.

Description: 

On page 70, the description: 

(protocol <expression>) 

<Expression> is evaluated in the same environment as the
define-record-type form, ...

does not clarify whether the protocol can refer to the predicates and
accessors of the same record type being defined. In other words, is
the following possible?

(define-record-type point 
  (fields (immutable x) 
          (immutable y)) 
  (protocol (lambda (p) 
              (case-lambda 
                ((x y) (p x y)) ; ordinary constructor
                ((pt) (p (point-x pt) ; copy existing point 
                         (point-y pt))))))) 

Here the usages of point-x and point-y are supposed to be the ones
being defined in the same define-record-type.

This is a very useful and reasonable thing to do.

Suggestion: 

Let the protocol <expression> be evaluated in the scope of the
bindings of the constructor, predicate, accessors and mutators being
defined in the define-record-type expression.

RESPONSE:

The comment was withdrawn as per

http://lists.r6rs.org/pipermail/r6rs-discuss/2006-November/001064.html