Re: string-ports issue on Windows

[Christopher Lam]

Hi Mark
Final update - first, we've reused your efficient substring-replace
function in
https://github.com/Gnucash/gnucash/commit/7d15e6e4e727c87fb4a501e924c4ae02276e508d
from a few years ago.
Second, the email thread
https://lists.gnu.org/archive/html/guile-devel/2014-03/msg00060.html
confirmed a lot of issues in guile-2.0 could be solved in Windows by
upgrading to guile-2.2. So, GnuCash has now upgraded to guile-2.2 on
Windows and the string-ports are now behaving.
Thank you (twice)
:)

On Fri, 19 Apr 2019 at 10:26, Christopher Lam <address@hidden>
wrote:

> Hi,
> The patch *does* work and handles unicode properly :) There are unintended
> consequences however, whereby other (probably C-based) string-code in
> Windows are now reading the lira-symbol into unexpected chars (eg
> lira-symbol -> "â‚°" i.e. #xe2 #x201a #xba) but this is now outside the
> scope of this post.
> Thank you again!
>
> On Thu, 18 Apr 2019 at 21:20, Mark H Weaver <address@hidden> wrote:
>
>> Hi again,
>>
>> Earlier, I wrote:
>>
>> > Christopher Lam <address@hidden> writes:
>> >
>> >> Hi Mark
>> >> Thank you so much for looking into this.
>> >> I'm reviewing the GnuCash for Windows package (v3.5 released April
>> 2019)
>> >> which contains the following libraries:
>> >> - guile 2.0.14
>> >
>> > Ah, for some reason I thought you were using Guile 2.2.  That explains
>> > the problem.
>> >
>> > In Guile 2.0, string ports internally used the locale encoding by
>> > default, which meant that any characters not supported by the locale
>> > encoding would be munged.
>> >
>> > Guile 2.2 changed the behavior of string ports to always use UTF-8
>> > internally, which ensures that all valid Guile strings can pass through
>> > unmunged.
>> >
>> > So, this problem would almost certainly be fixed by updating to
>> > Guile 2.2.
>>
>> It's probably a good idea to update to Guile 2.2 anyway, but I'd like to
>> also offer the following workaround, which monkey patches the string
>> port procedures in Guile 2.0 to behave more like Guile 2.2.
>>
>> Note that it only patches the Scheme APIs for string ports, and not the
>> underlying C functions.  It might be that some code, possibly within
>> Guile itself, creates a string port using the C functions, and such
>> string ports may still munge characters.
>>
>> Anyway, if you want to try it, arrange for GnuCash to evaluate the code
>> below, after initializing Guile.
>>
>>       Mark
>>
>>
>> (when (string=? (effective-version) "2.0")
>>   ;; When using Guile 2.0.x, use monkey patching to change the
>>   ;; behavior of string ports to use UTF-8 as the internal encoding.
>>   ;; Note that this is the default behavior in Guile 2.2 or later.
>>   (let* ((mod                     (resolve-module '(guile)))
>>          (orig-open-input-string  (module-ref mod 'open-input-string))
>>          (orig-open-output-string (module-ref mod 'open-output-string))
>>          (orig-object->string     (module-ref mod 'object->string))
>>          (orig-simple-format      (module-ref mod 'simple-format)))
>>
>>     (define (open-input-string str)
>>       (with-fluids ((%default-port-encoding "UTF-8"))
>>         (orig-open-input-string str)))
>>
>>     (define (open-output-string)
>>       (with-fluids ((%default-port-encoding "UTF-8"))
>>         (orig-open-output-string)))
>>
>>     (define (object->string . args)
>>       (with-fluids ((%default-port-encoding "UTF-8"))
>>         (apply orig-object->string args)))
>>
>>     (define (simple-format . args)
>>       (with-fluids ((%default-port-encoding "UTF-8"))
>>         (apply orig-simple-format args)))
>>
>>     (define (call-with-input-string str proc)
>>       (proc (open-input-string str)))
>>
>>     (define (call-with-output-string proc)
>>       (let ((port (open-output-string)))
>>         (proc port)
>>         (get-output-string port)))
>>
>>     (module-set! mod 'open-input-string       open-input-string)
>>     (module-set! mod 'open-output-string      open-output-string)
>>     (module-set! mod 'object->string          object->string)
>>     (module-set! mod 'simple-format           simple-format)
>>     (module-set! mod 'call-with-input-string  call-with-input-string)
>>     (module-set! mod 'call-with-output-string call-with-output-string)
>>
>>     (when (eqv? (module-ref mod 'format) orig-simple-format)
>>       (module-set! mod 'format simple-format))))
>>
>