bug#22446: (rnrs hashtables): Hash functions of eq? and eqv? hashtables

[Andy Wingo <wingo@pobox.com>]

Applied, thanks :)

On Tue 21 Jun 2016 00:34, taylanbayirli@gmail.com (Taylan Ulrich "Bayırlı/Kammer") writes:

> Also pinging this thread with a (very slightly) updated patch. :-)
>
>
> From 17599f6ce7ba0beb100e80455ff99af07333d871 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Taylan=20Ulrich=20Bay=C4=B1rl=C4=B1/Kammer?=
>  <taylanbayirli@gmail.com>
> Date: Tue, 21 Jun 2016 00:23:29 +0200
> Subject: [PATCH] Hashtable-hash-function returns #f on eq and eqv tables.
>
> * module/rnrs/hashtables.scm (r6rs:hashtable)[type]: New field.
> (r6rs:hashtable-type): New procedure.
> * test-suite/tests/r6rs-hashtables.test: Add related tests.
> ---
>  module/rnrs/hashtables.scm            | 22 +++++++++++++++-------
>  test-suite/tests/r6rs-hashtables.test |  6 +++++-
>  2 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/module/rnrs/hashtables.scm b/module/rnrs/hashtables.scm
> index 98d2d76..08f37e2 100644
> --- a/module/rnrs/hashtables.scm
> +++ b/module/rnrs/hashtables.scm
> @@ -74,8 +74,9 @@
>      (make-record-type-descriptor 
>       'r6rs:hashtable #f #f #t #t 
>       '#((mutable wrapped-table)
> -	(immutable orig-hash-function)
> -	(immutable mutable))))
> +        (immutable orig-hash-function)
> +        (immutable mutable)
> +        (immutable type))))
>  
>    (define hashtable? (record-predicate r6rs:hashtable))
>    (define make-r6rs-hashtable 
> @@ -85,6 +86,7 @@
>    (define r6rs:hashtable-set-wrapped-table! (record-mutator r6rs:hashtable 0))
>    (define r6rs:hashtable-orig-hash-function (record-accessor r6rs:hashtable 1))
>    (define r6rs:hashtable-mutable? (record-accessor r6rs:hashtable 2))
> +  (define r6rs:hashtable-type (record-accessor r6rs:hashtable 3))
>  
>    (define hashtable-mutable? r6rs:hashtable-mutable?)
>  
> @@ -96,13 +98,15 @@
>      (make-r6rs-hashtable 
>       (if k (make-hash-table eq? hashq k) (make-hash-table eq? symbol-hash))
>       symbol-hash
> -     #t))
> +     #t
> +     'eq))
>  
>    (define* (make-eqv-hashtable #:optional k)
>      (make-r6rs-hashtable 
>       (if k (make-hash-table eqv? hashv k) (make-hash-table eqv? hash-by-value))
>       hash-by-value
> -     #t))
> +     #t
> +     'eqv))
>  
>    (define* (make-hashtable hash-function equiv #:optional k)
>      (let ((wrapped-hash-function (wrap-hash-function hash-function)))
> @@ -111,7 +115,8 @@
>  	   (make-hash-table equiv wrapped-hash-function k)
>  	   (make-hash-table equiv wrapped-hash-function))
>         hash-function
> -       #t)))
> +       #t
> +       'custom)))
>   
>    (define (hashtable-size hashtable)
>      (hash-table-size (r6rs:hashtable-wrapped-table hashtable)))
> @@ -143,7 +148,8 @@
>      (make-r6rs-hashtable 
>       (hash-table-copy (r6rs:hashtable-wrapped-table hashtable))
>       (r6rs:hashtable-orig-hash-function hashtable)
> -     (and mutable #t)))
> +     (and mutable #t)
> +     (r6rs:hashtable-type hashtable)))
>  
>    (define* (hashtable-clear! hashtable #:optional k)
>      (if (r6rs:hashtable-mutable? hashtable)
> @@ -178,4 +184,6 @@
>      (hash-table-equivalence-function (r6rs:hashtable-wrapped-table hashtable)))
>  
>    (define (hashtable-hash-function hashtable)
> -    (r6rs:hashtable-orig-hash-function hashtable)))
> +    (case (r6rs:hashtable-type hashtable)
> +      ((eq eqv) #f)
> +      (else (r6rs:hashtable-orig-hash-function hashtable)))))
> diff --git a/test-suite/tests/r6rs-hashtables.test b/test-suite/tests/r6rs-hashtables.test
> index c7812c5..fbc50c9 100644
> --- a/test-suite/tests/r6rs-hashtables.test
> +++ b/test-suite/tests/r6rs-hashtables.test
> @@ -174,7 +174,11 @@
>  (with-test-prefix "hashtable-hash-function"
>    (pass-if "hashtable-hash-function returns hash function"
>      (let ((abs-hashtable (make-hashtable abs eqv?)))
> -      (eq? (hashtable-hash-function abs-hashtable) abs))))
> +      (eq? (hashtable-hash-function abs-hashtable) abs)))
> +  (pass-if "hashtable-hash-function returns #f on eq table"
> +    (eq? #f (hashtable-hash-function (make-eq-hashtable))))
> +  (pass-if "hashtable-hash-function returns #f on eqv table"
> +    (eq? #f (hashtable-hash-function (make-eqv-hashtable)))))
>  
>  (with-test-prefix "hashtable-mutable?"
>    (pass-if "hashtable-mutable? is #t on mutable hashtables"