Hello,
In the thread about creating custom metronome markups
(http://lists.gnu.org/archive/html/lilypond-user/2008-04/msg00629.html)
and the subsequent discussion at The LilyPond Report, Valentin
expressed the wish for a convenient way to convert duration strings to
durations. Since I agreed, I thought I'd have a go at implementing an
exported scheme function in duration-scheme.cc which can be used
within lilypond files.
Attached is a patch with "My First C++ Code", which provides this
functionality. :)
Regards,
Neil
From a33b00dd24d4174e6279e9afb66e3ff719767d53 Mon Sep 17 00:00:00 2001
From: Neil Puttock <[EMAIL PROTECTED]>
Date: Fri, 16 May 2008 19:41:36 +0100
Subject: [PATCH] Scheme function ly:string->duration
---
lily/duration-scheme.cc | 50 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/lily/duration-scheme.cc b/lily/duration-scheme.cc
index d371475..2b03862 100644
--- a/lily/duration-scheme.cc
+++ b/lily/duration-scheme.cc
@@ -7,8 +7,13 @@
Han-Wen Nienhuys <[EMAIL PROTECTED]>
*/
+#include <sstream>
+using namespace std;
+
#include "duration.hh"
+#include "international.hh"
#include "misc.hh"
+#include "warn.hh"
MAKE_SCHEME_CALLBACK (Duration, less_p, 2);
SCM
@@ -136,3 +141,48 @@ LY_DEFINE (ly_duration_factor, "ly:duration-factor",
Rational r = unsmob_duration (dur)->factor ();
return scm_cons (scm_from_int (r.num ()), scm_from_int (r.den ()));
}
+
+LY_DEFINE (ly_string_2_duration, "ly:string->duration",
+ 1, 0, 0, (SCM str),
+ "Convert @var{str} to a duration.")
+{
+ LY_ASSERT_TYPE (scm_is_string, str, 1);
+ string s = ly_scm2string (str);
+ stringstream stream (s);
+ int len = 0;
+ int dots = 0;
+ size_t pos = 0;
+
+ while (pos !=NPOS)
+ {
+ pos = s.find (".", pos);
+ if (pos != NPOS)
+ {
+ dots++;
+ pos++;
+ }
+ }
+ s = s.substr (0, (s.length () - dots));
+
+ stream >> len;
+ if (!stream.fail () && (len && len == 1 << intlog2 (len)))
+ len = intlog2 (len);
+ else
+ {
+ if (s == "breve")
+ len = -1;
+ else if (s == "longa")
+ len = -2;
+ else if (s == "maxima")
+ len = -3;
+ else
+ {
+ len = 0;
+ dots = 0;
+ warning (_ ("invalid duration string, setting to whole note"));
+ }
+ }
+
+ Duration p (len, dots);
+ return p.smobbed_copy ();
+}
--
1.5.4.3
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