Not a duration. Why not?

[Trevor Skeggs]

Is it OK to post suggestions on this site?
(I could not find any link for such in the Lilypond site, 
 other than for documentation changes).


1). If a note duration such as c3 is detected, an error message is issued:

    error: not a duration: 3

    Why should 3 not be a valid duration, mid-way between 2 and 4?
    (It would have the same value as a dotted 4).

    After all, if the program is going to the trouble of weeding-out 
    these values and printing an error message, it may just as well 
    substitute the code for a dotted 4 !

    Similarly, 6 should be a valid code equivalent to a dotted eigth-note.  

    [Why did I enter a 3? Because, decades ago, I wrote an music interpreter 
     program for a Z80 that used exactly these codes. I had a mental relapse!]
 

2). Currently, if an stand-alone number is detected, a complier error is issued:
    error: syntax error, unexpected DIGIT

    Why should this be so?
    What else can such a number represent, other than a duration?

    Previous notes are "memorised" for used in relative mode calculations.
    Why then shouldn't it be possible to type a "quick note", e.g.:

    c2 8 8 4 d1 ?


3). The convenience of omitting a duration when it is the same as the previous
    note is frequently upset by the requirement for a dotted note.
    Dotted notes usually "steal time" from the following notes: 
    
    g4  g8. g16 a4 g8. g16  g4  f8. e16  d2  (chorus from "Waltzing Matilda")
            

    If the previous two suggestions were to be merged, then would it be 
    possible to reserve durations 3 and 6 as a special case?

    In this special case, the duration of the preceding note is "remembered"
    and stached away. The 3 or 6 temporarily sets-up a duration of a dotted 
    4 or 8 and sets a flag.  After the note is completed, the presence
    of this flag over-rides the next note duration to be a 8 or 16.

    The original duration stored-away is then restored.

    That means the above music sequence can be written in "quick" style as:

    g4 3 g a g3 g g  f3 e d2  

    The stand-alone 3 signifies that the previous pitch is to be used.
    The g following the 3 is the pitch of the automatic 16th-note.
    The a following the g is restored to the original quarter-note.