Re: Creating new articulation (adding to an internal alist)

[David Nalesnik]

On Fri, Mar 6, 2015 at 7:24 AM, David Nalesnik <address@hidden> wrote:

 \version "2.19.16"

#(set! default-script-alist

       (append default-script-alist

         (list

          `("weakbeat"

             . (

                 (script-stencil . (feta . ("weakbeat" . "weakbeat")))

                 ; any other properties

                 (toward-stem-shift-in-column . 0.0)

                 (padding . 0.20)

                 (avoid-slur . around)

                 (direction . ,UP))))))

weakbeat = #(make-articulation "weakbeat")

{ c\weakbeat }

\layout {

  \context {

    \Score

    scriptDefinitions = #default-script-alist

  }

}

%%%

Here's my conclusion:

When using append, we are setting default-script-alist to a list which doesn't necessarily share structure with the original default-script-alist.  scriptDefinitions is bound to the original default-script-alist unless you reassign it to the concatenated list.  append! destructively modifies the list that scriptDefinitions is bound to, so there is no need for the set in the context block. 

--David