Re: Custom Format

[Aaron Hill]

On 2021-03-30 5:30 pm, Callum Cassidy-Nolan wrote:
> [...]
> I would love to use it, but I have a particular way I interact with 
> music.
>
> Particularly I don't use letter names, but instead I use numbers, to
> understand what I mean, please take a look at my document:
> https://gitlab.com/cuppajoeman/music/-/blob/master/diagrams/standard_to_semitones.pdf
>
> I just saw a basic example in the documentation, something like this:
>
> \version "2.22.0"
> {
>   c' e' g' e'
> }
>
> In my system I would write something like this:
>
> \version "2.22.0"
> {
>   0' 4' 7' 4'
> }
> [...]

Not sure why I have done this, but here are some rather horrendous* 
things that can be accomplished entirely within LilyPond so as to not 
require pre-processing:

(* This is entering the nearly indecipherable territory of esoteric 
languages.)

%%%%
\version "2.22.0"

%% -----
%% Option 1:
%% Use a procedure to convert a number to pitch:
#(define (: n)
  (apply
   ly:make-pitch
   (cons (1- (floor (/ n 12)))
         (list-ref `((0 0) (0 ,SHARP) (1 0) (1 ,SHARP)
                     (2 0) (3 0) (3 ,SHARP) (4 0)
                     (4 ,SHARP) (5 0) (5 ,SHARP) (6 0))
                   (modulo n 12)))))

{ $(: 0)' 8. $(: 9) 16 $(: 2)' $(: 6)' $(: 9)' 8 $(: 4)'' 2 }

%% Pros:
%%  - Values outside the interval [0,11] work.
%%  - Octave marks can appear snugly next to the expression.
%% Cons:
%%  - Requires five extra characters to input than the number,
%%    assuming the procedure is named with a single character.
%% -----
%% Option 2:
%% Define appropriately named variables with pitches:

defineNoteIndices =
#(define-void-function
  (music) (ly:music?)
  (let ((pitches (music-pitches music)))
   (for-each
    (lambda (idx pitch)
     (module-define! (current-module)
      (string->symbol (format #f ":~a" idx)) pitch))
    (iota (length pitches))
    pitches)))

\defineNoteIndices { c cis d dis e f fis g gis a ais b }

{ $:0 ' 8. $:9 16 $:2 ' $:6 ' $:9 ' 8 $:4 '' 2 }

%% Pros:
%%  - Can work with as many or as few notes as needed.
%%    (Think of pentatonic music without alterations.)
%%  - Easier to customize as pitches are entered naturally.
%%  - Only two additional characters to input a pitch*.
%% Cons:
%%  - Only supports exactly as many indices as defined.
%%  - Whitespace needed between pitch and octave mark.
%%    * So potentially, three additional characters needed.
%% -----
%%%%

NOTE: I only used a colon above as it was not yet a defined symbol.  
However, colons are used in LilyPond syntax as the short-hand for 
tremolo repeats.  So, almost certainly a different character would be 
better.


-- Aaron Hill

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