LilyIssues / Issues / #4645 Use a MelismaEvent for \melisma

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#4645 Use a MelismaEvent for \melisma

Status: Accepted

Owner: nobody

Labels: None

Needs:

Patch:

Type: Enhancement

Updated: 2015-10-27

Created: 2015-10-26

Creator: Simon Albrecht

Private: No

Currently, \melisma and \melismaEnd are defined (in ly/declarations-init.ly) as:

:::Scheme
melisma = #(context-spec-music (make-property-set 'melismaBusy #t) 'Bottom)
melismaEnd = #(context-spec-music (make-property-unset 'melismaBusy) 'Bottom)

whereas slurs, ligatures and beams use events and the respective melismaBusyProperties are set ‘behind the scenes’. The difference is that \melisma[End] are thus executed at the next timestep, while the events belonging to other melisma-related objects happen at the timestep of the note to which they are attached.

The inconsistency alone would not matter, but it does provide an ‘unnecessary’ difficulty: one must remember to always have \melisma last, i.e. after all post-events. This is more difficult with e.g.

"(" = \melisma
")" = \melismaEnd

applied, which is an important feature in producing different editions (following different conventions of notating melismata) from the same source. For example, { c8([ d)] } is valid and common coding AFAICS, but with the above redefinition it doesn’t work (Error: unexpected post-event).

Discussion

Description has changed:

Diff:

--- old
+++ new
@@ -6,33 +6,11 @@
 melismaEnd = #(context-spec-music (make-property-unset 'melismaBusy) 'Bottom)
 ~~~~

-whereas slurs, ligatures and beams use events and the respective `melismaBusyProperties` are set ‘behind the scenes’. A crucial difference is that \melisma[End] are thus executed at the _next_ timestep, while the events belonging to other melisma-related objects happen at the timestep of the note to which they are attached.
+whereas slurs, ligatures and beams use events and the respective `melismaBusyProperties` are set ‘behind the scenes’. The difference is that \melisma[End] are thus executed at the _next_ timestep, while the events belonging to other melisma-related objects happen at the timestep of the note to which they are attached.

-There may not be many use cases where this makes a difference, but it has the following two downsides (apart from the inconsistency I see):
-
-1– One must remember to always have \melisma last, i.e. after all post-events. This is more difficult with e.g.
+The inconsistency alone would not matter, but it does provide an ‘unnecessary’ difficulty: one must remember to always have \melisma last, i.e. after all post-events. This is more difficult with e.g.

     "(" = \melisma
     ")" = \melismaEnd

 applied, which is an important feature in producing different editions (following different conventions of notating melismata) from the same source. For example, `{ c8([ d)] }` is valid and common coding AFAICS, but with the above redefinition it doesn’t work (Error: unexpected post-event).
-
-2– It is not possible to redefine \melisma so that it enables automatic beaming for the duration of the melisma. The following:
-
-~~~~
-:::Scheme
-melisma =
-#(context-spec-music (make-sequential-music
-                      (list (make-property-set 'melismaBusy #t)
-                        (make-property-set 'autoBeaming #t)))
-   'Bottom)
-melismaEnd =
-#(context-spec-music (make-sequential-music
-                      (list (make-property-unset 'melismaBusy)
-                        (make-property-set 'autoBeaming #f)))
-   'Bottom)
-~~~~
-
-amongst other malfunctions (which I don’t understand yet) doesn’t beam the first note of the melisma (and will continue autoBeaming until the first note after the melisma).
-
-This is certainly of low priority, but I think it’s not invalid.

Simon Albrecht - 2015-10-27

I cancelled the second topic from this issue, because 1) I underestimated (of course, sorry) the complications which arise and 2) it’s another issue.

If you would like to refer to this comment somewhere else in this project, copy and paste the following link:

Simon Albrecht - 2015-10-27

And I raised https://sourceforge.net/p/forge/site-support/11453/ on behalf of the mess in the diff above (first comment).

If you would like to refer to this comment somewhere else in this project, copy and paste the following link:

Use a MelismaEvent for \melisma

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#4645 Use a MelismaEvent for \melisma

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