Re: chord with notes of different duration

[Marc Mouries]

 On 10/6/2010 3:44 PM, Carl Sorensen wrote:
> Learning Manual section 4.1.4.
thanks for pointing me in the right direction. However the page you 
pointed me to was not helpful as it dealt only with color tweaks but 
then i googled "tweak duration" and then found the page:
http://www.kainhofer.com/~lilypond/ajax/Documentation/notation/the-tweak-command.nl.html
which contained the following snippet:
< c \tweak #'color #red d g \tweak #'duration-log #1 a > 4

<g d' b'  \tweak #'duration-log #1 g'>4 s4}


It is really not clear:
1) why the property is called duration-log and not just duration?
2) why the duration parameter must be #1 while the duration is a half note?
3) why a skip is needed whereas the top note is a half note (otherwise 
the measure is not complete)?

-Marc