Re: GNU Guile 2.9.9 Released [beta]

[Stefan Israelsson Tampe]

1. I don't understand why you decrement the count in operator position

2. I don't see that you increase the count when a procedure is returned from a lambda

Example

(define (f a) a)

(define (g)

    (hash-set! H f 1) ; (*)

    (f 1)) ;(**)

(define (h)

   (pk (hash-ref H f))) ; (*)

(g)

(h)

=> '(#f) as count in your patch is counted up twice (*) and down ones (**) in total count = 1 so you will not maintain the identity of f and you will get a bad printout

Then we also have this example

(define (f a) a)

(define (u) f)

(define (g) (hash-set! H (u) 1))

(define (h) (pk (hash-ref H f)))

(g)

(h)

This will again print (#f) as the count will be 1.

/Stefan

    

On Tue, Jan 14, 2020 at 5:16 PM Andy Wingo <address@hidden> wrote:

On Tue 14 Jan 2020 15:47, Stefan Israelsson Tampe <address@hidden> writes:

> Yes, your patch is indicating when you should use the same identity
> e.g. all uses of procedures in a higher order position such as an
> argument or a return value. But I looked at your patch, which looks
> good but I saw that for operator position you decrease the count. Why?
> Also you are free to use one version in argument / return position and
> another one in operator position the only limit is to use the same
> identity for on operator position. Finally don't you need to count
> usage of returning a variable as well?

Not sure what the bug is.  Do you have a test case that shows the
behavior that you think is not good?

Andy