bug#10621: Incorrect usage of hash procedures in (ice-9 mapping)

[Daniel Hartwig <mandyke@gmail.com>]

Mark H Weaver <mhw@netris.org> wrote:
> ice-9/mapping.scm:97:48: warning: possibly wrong number of arguments to `hashx-get-handle'
> ice-9/mapping.scm:94:48: warning: possibly unbound variable `hashx-create-handle'

This module is quite ancient, and, in addition to these warnings, has
not worked for some time.  Some logic errors in hash-table-mapping
(detecting len) and mapping-ref (detecting dflt), for example.  Since
noone has reported the brokenness I guess that means the module has no
users.

There is no practical way to accomodate a separate delete-proc, as
hashx-remove! uses assoc.  The use of delq! and others to convey the
intended delete semantics is incorrect, since mapping-remove! actually
presents and expects a different interface, that of hashq-remove!.

There is no documentation.

It seems the main purpose of this module is to associate hash and assoc
procedures with a hash table, and so provide a single set of accessors
(rather than one for each of hashq, hashv, etc.).  This is more-or-less
handled by both srfi-69 and rnrs hashtables.

A short module, it is not hard to fix, though given all of the above it
makes sense to simply remove it.