Use our own ~s ly:format placeholder, since guile is broken with wide chars

Use our own ~s ly:format placeholder, since guile is broken with wide chars

We need our own ~S format placeholder to escape quotes, so use
lilypond's string formating to make wide utf-8 chars work in filenames

Guile seems unable to handle wide characters, so we mustn't use
simple-format or format, because that will break with non-ANSI characters
(char code > 255). Instead, Implement our own ~S placeholder, that
wraps the string in double quotes and escapes backslashes and double
quotes.

Use this format placeholder to generate the proper cmd line args
for our calls to gs.

[joeneeman, 2009-08-21 22:59:33]

http://codereview.appspot.com/109070/diff/1/2
File lily/general-scheme.cc (right):

http://codereview.appspot.com/109070/diff/1/2#newcode437
Line 437: replace_all (&s, "\"", "\\\"");
Don't forget to escape $. Or else use single quotes rather than double quotes.

[Patrick McCarty, 2009-08-21 23:49:51]

http://codereview.appspot.com/109070/diff/1/2
File lily/general-scheme.cc (right):

http://codereview.appspot.com/109070/diff/1/2#newcode432
Line 432: else if (scm_is_string (arg)) {
Can you also fix the indentation (move open brace to next line) and below
likewise?

[Reinhold, 2009-08-22 00:11:34]

http://codereview.appspot.com/109070/diff/1/2
File lily/general-scheme.cc (right):

http://codereview.appspot.com/109070/diff/1/2#newcode437
Line 437: replace_all (&s, "\"", "\\\"");
On 2009/08/21 22:59:33, joeneeman wrote:
> Don't forget to escape $. Or else use single quotes rather than double quotes.

Good catch. $ needs to be escaped, too. Using single quotes does not work with
gs.

[joeneeman, 2009-08-22 00:28:39]

On 2009/08/22 00:11:34, Reinhold wrote:
> http://codereview.appspot.com/109070/diff/1/2
> File lily/general-scheme.cc (right):
> 
> http://codereview.appspot.com/109070/diff/1/2#newcode437
> Line 437: replace_all (&s, "\"", "\\\"");
> On 2009/08/21 22:59:33, joeneeman wrote:
> > Don't forget to escape $. Or else use single quotes rather than double
quotes.
> 
> Good catch. $ needs to be escaped, too. Using single quotes does not work with
> gs.

Well, it should be the shell that sees the quotes, not gs. Perhaps you're using
cmd.exe and it doesn't like single quotes? Which brings up the issue that the
escaping/quoting rules are different between windows and linux, so you'd need to
test which system lilypond is running on...

Unless you use guile's system* function instead of system, which doesn't run a
shell and hence needs no escaping or quoting. That's probably a safer and
simpler approach.

[Ian Hulin, 2009-08-22 12:29:57]

If we're covering shell variables for Windows, like $ for *ix, we'd need to
escape "%" character, too.
That way we'd handle cmd variables like %HOME% or %PATH%.

http://codereview.appspot.com/109070/diff/15/16
File lily/general-scheme.cc (right):

http://codereview.appspot.com/109070/diff/15/16#newcode440
Line 440: replace_all (&s, "$", "\\$");
You would need to add 
replace_all (&s, "%", "\\%"); 
to cover the similar case to "$" for Windows (shell variable substituion)