Re: Determining what parameters exist for an item

[David Kastrup]

Kieren MacMillan <address@hidden> writes:

> Hi Carl,
>
>> 4) Going to one of these interfaces […]
>> provides a list of user-settable properties for that interface
>
> Yes, but unless I’m missing something, you can’t find the default
> value(s) there, right?

Interfaces don't have default values.  Grobs have.

> I personally would love to be able to get, for any grob, a list of
> every settable value (“native” or “interfaced”) *including the default
> value for each setting*.

You mean, something like


3.1.24 ChordName
----------------

ChordName objects are created by: *note Chord_name_engraver::.

   Standard settings:

     ‘after-line-breaking’ (boolean):
          ‘ly:chord-name::after-line-breaking’

          Dummy property, used to trigger callback for
          ‘after-line-breaking’.

     ‘extra-spacing-height’ (pair of numbers):
          '(0.2 . -0.2)

          In the horizontal spacing problem, we increase the height of
          each item by this amount (by adding the ‘car’ to the bottom of
          the item and adding the ‘cdr’ to the top of the item).  In
          order to make a grob infinitely high (to prevent the
          horizontal spacing problem from placing any other grobs above
          or below this grob), set this to ‘(-inf.0 . +inf.0)’.

     ‘extra-spacing-width’ (pair of numbers):
          '(-0.5 . 0.5)

          In the horizontal spacing problem, we pad each item by this
          amount (by adding the ‘car’ on the left side of the item and
          adding the ‘cdr’ on the right side of the item).  In order to
          make a grob take up no horizontal space at all, set this to
          ‘(+inf.0 . -inf.0)’.

     ‘font-family’ (symbol):
          ‘'sans’

          The font family is the broadest category for selecting text
          fonts.  Options include: ‘sans’, ‘roman’.

     ‘font-size’ (number):
          ‘1.5’

          The font size, compared to the ‘normal’ size.  ‘0’ is
          style-sheet’s normal size, ‘-1’ is smaller, ‘+1’ is bigger.
          Each step of 1 is approximately 12% larger; 6 steps are
          exactly a factor 2 larger.  If the context property ‘fontSize’
          is set, its value is added to this before the glyph is
          printed.  Fractional values are allowed.

     ‘stencil’ (stencil):
          ‘ly:text-interface::print’

          The symbol to print.

     ‘word-space’ (dimension, in staff space):
          ‘0.0’

          Space to insert between words in texts.

     ‘Y-extent’ (pair of numbers):
          ‘#<unpure-pure-container #<primitive-procedure
          ly:grob::stencil-height> >’

          Extent (size) in the Y direction, measured in staff-space
          units, relative to object’s reference point.

-- 
David Kastrup