Re: guile-2.0 and debian

[Antonio Ospite]

On Sun, 20 Nov 2016 01:12:59 +0100
Thomas Morley <address@hidden> wrote:

> Hi,
> 
> for now I looked only at a single problem, the meta-data. (Giving me a
> royal headache)
> 
> 2016-11-19 16:05 GMT+01:00 Antonio Ospite <address@hidden>:
> 
> > The following change fixes the issue at hand:
> >
> > ---------------------------------------------------------------------
> > diff --git a/scm/framework-ps.scm b/scm/framework-ps.scm
> > index a404119..b2b6802 100644
> > --- a/scm/framework-ps.scm
> > +++ b/scm/framework-ps.scm
> > @@ -28,6 +28,9 @@
> >               (scm clip-region)
> >               (lily))
> >
> > +(if (guile-v2)
> > +  (use-modules(rnrs bytevectors)))
> > +
> >  (define format ergonomic-simple-format)
> >
> >  (define framework-ps-module (current-module))
> > @@ -518,15 +521,22 @@
> >    (define (metadata-encode val)
> >      ;; First, call ly:encode-string-for-pdf to encode the string (Latin1 or
> >      ;; utf-16be), then escape all parentheses and backslashes
> > -    ;; FIXME guile-2.0: use (string->utf16 str 'big) instead
> > +    ;; With guile-2.0: use (string->utf16 str 'big) instead
> > +    (if (guile-v2)
> > +      (ps-quote (utf16->string (string->utf16 val 'big)))
> 
> Well, the line above does not make much sense, because val is
> effectively returned unchanged, before ps-quote does it's work. See:
> (string=? (utf16->string (string->utf16 "ちりぬるを)" 'big)) "ちりぬるを)")
> --> #t
>

You are right, I didn't understand that the actual representation in
UTF-16 was done below when setting the port encoding, and not here.

I am new to guile and I am still doing something "by coincidence".

> > +      (ps-quote (ly:encode-string-for-pdf val))))
> >
> > -    (ps-quote (ly:encode-string-for-pdf val)))
> >    (define (metadata-lookup-output overridevar fallbackvar field)
> >      (let* ((overrideval (ly:modules-lookup (list header) overridevar))
> >             (fallbackval (ly:modules-lookup (list header) fallbackvar))
> >             (val (if overrideval overrideval fallbackval)))
> >        (if val
> > -          (format port "/~a (~a)\n" field (metadata-encode (markup->string 
> > val (list header)))))))
> > +        (begin
> > +          (format port "/~a (" field)
> > +          (set-port-encoding! port "UTF-16")
> > +          (format port "~a" (metadata-encode (markup->string val (list 
> > header))))
> > +          (set-port-encoding! port "ISO-8859-1")
> > +          (format port ")\n")))))
> >
> >    (if (module? header)
> >        (begin
> > ---------------------------------------------------------------------
> >
> > This is rather ugly, but encoding only the actual _value_ of the field
> > in UTF-16 allows to have exactly the same output as with guile-1.8.
> 
> Well, this example gives a gs-error again:
> 
> \header { title = "ちりぬるを)" } \markup \null
>

The problem here is that, when writing to the postscript file, the
escaping is (mistakenly) done before the encoding, so the escaped "\)"
gets represented in UTF-16 as "address@hidden@)" which makes the ')' not really
escaped anymore and ghostscript fails.

I'll try to come up with a better solution for this problem.

Ciao,
   Antonio

-- 
Antonio Ospite
https://ao2.it
https://twitter.com/ao2it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?