purescript-vexflow

Purescript wrapper for VexFlow notation. Based on an original implementation by @marcoalkema, this version has syntax closer to that of the original VexFlow library using programmable semicolons (i.e. Monads) ala purescript-d3.

Also provides some type level safety, your code wil not compile if you try to call getContext before calling setContext, for example.

###Example Here's an example of a bar created in JavaScript, taken from the VexFlow wiki:

var notes = [
  new VF.StaveNote({clef: "treble", keys: ["c/4"], duration: "q" }),
  new VF.StaveNote({clef: "treble", keys: ["d/4"], duration: "q" }),
  new VF.StaveNote({clef: "treble", keys: ["b/4"], duration: "qr" }),
  new VF.StaveNote({clef: "treble", keys: ["c/4", "e/4", "g/4"], duration: "q" })
];

var voice = new VF.Voice({num_beats: 4,  beat_value: 4});
voice.addTickables(notes);

var formatter = new VF.Formatter().joinVoices([voice]).format([voice], 400);

voice.draw(context, stave);

The equivalent PureScript would be

  notes <- sequence
    [ note Treble [c Natural 4] quarter
    , note Treble [d Natural 4] quarter
    , note Treble [b Natural 4] quarterRest
    , note Treble [c Natural 4, e Natural 4, g Natural 4] quarter
    ]
  
  voice <- newVoice (Voice (TimeSignature 4 4))
    .. addTickables notes
    .. setContext ctx
    .. setStave stave

  formatter <- newFormatter
    .. joinVoices [build voice]
    .. format [build voice] 400.0

  drawVoice voice

There are more examples in the /Test folder.

#To Do:

###Typelevel safety

Enforce setContext before getContext
Enforce setStave before getStave
Require that the duration of notes in a voice sum to one bar length
Require addAccidental, addDot and other functions that target specific notes in a StaveNote to only target notes that exists in that StaveNote, i.e. you can't add an accidental to the 4th note if there are only three notes.

###Features

###EasyScore VexFlow provides freedom to notate music the way one chooses, but this comes at the cost of extra complexity. Notes with flats/sharps do not automatically have those flats/sharps rendered, notes are not automatically beamed, etc.

Given that VexFlow is a JavaScript library

Add EasyScore analogous to VexFlow's EasyScore