Re: How to store lengths in variables

[Jan-Peter Voigt]

Hi Urs,

as you already said units are only known inside the paper block, because 
they are dependent of the paper size an the global staff size. Inside 
the paper block the units are just numbers. If you want to multiply 
numbers you can do so outside the paper block like this:

xx = 2
yy = 3\xx
#(display yy) % will display '6'

One idea might be to store pairs or lists with the number and the unit 
name as a symbol. Inside the paper block a scheme-function can retrieve 
the unit factor and multiply it with the given value.

A rough sketch is attached.

HTH
Jan-Peter

Am 12.12.2017 um 11:40 schrieb Urs Liska:
> Hi,
>
> I would like to parametrize my paper settings. But for that I need to 
> either store the measurement unit in a variable (outside the paper 
> block) or store the plain number in the variable and create a length 
> from that within the paper block.
>
> tm = 5\in
>
> \paper {
>    top-margin = #tm
> }
>
> This doesn't work because LilyPond doesn't recognize the "\in" in the 
> toplevel variable definition.
>
> And rather than using the LilyPond syntax I would need to store the 
> settings in an alist like
>
> values =
> #'((top-margin . 5)
>     (bottom-margin . 2.5))
>
> etc. and retrieve those values in the paper definition.
>
> So I need to either store the numbers together with their unit (so I can 
> directly use them in the paper block) or have a way to "create" that 
> variable from the stored number within the paper block.
>
> Any pointers appreciated
> Urs
>
>
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paper-value.ly
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