What is relanote?

relanote is a pure functional, statically-typed language for music. It has a single big idea: everything is relative. Pitch is relative. Rhythm is relative. Chords are intervals over a root, sections are blocks over a beat-grid, parts are sections over an instrument, layers are parts over time. A line is the relationship between its notes; nothing in the language pins music to where it absolutely sits.

That's not a stylistic preference. It's the entire design.

Pitch is relative

Conventional notation and most code-based approaches tie pitches to absolute positions: C4, D4, E4. That's fine for engraving — and the worst possible shape for software. Transpose a melody and every pitch needs rewriting. Try a different mode and you start over. The musical idea is hidden inside the encoding.

relanote describes lines by their scale-degree references instead:

rela

scale Major = { R, M2, M3, P4, P5, M6, M7 }

; Five degrees, in any key, in any mode.
let theme = | <1> <3> <5> <3> <1> |

<1> is the root, <3> is the third, <5> is the fifth — of whatever scale is in scope. The same five symbols play C-E-G-E-C in C major, G-B-D-B-G in G major and D-F-A-F-D in D minor. Switching key is one edit. Switching mode is one edit. Transposing for a different instrument is one function call:

rela

theme |> transpose P5

Rhythm is relative

Conventional notation pins rhythm to absolute durations too — quarter notes, eighth notes, milliseconds. relanote's blocks share a slot equally among the notes inside them:

rela

; Four notes share the slot equally.
let fast = | <1> <3> <5> <3> |

; Two notes share the same slot — each at half the density of `fast`.
let slow = | <1> <5> |

; Both blocks take the same total time. Density is what changed.
fast ++ slow

Tempo changes the *length* of the slot, not the *shape* inside it. Double the tempo and you don't rewrite anything.

Everything else, recursively

Once pitch and rhythm are relative, the rest follows. A chord is intervals over a root. A section is blocks over a beat-grid. A part is a section played by an instrument. A layer is parts running in parallel. The whole language is built out of relationships, and the runtime unwinds them when it's time to produce sound.

Functional, pure, typed

relanote is also a programming language, with the things you'd expect:

Immutable values. Transformations return new values; the originals

never change.

First-class functions. Pass them, compose them, store them.
Pure functions. No hidden state, no surprise side effects.
Hindley-Milner type inference. The type checker rejects programs

that would have produced nonsense at runtime.

rela

scale Major = { R, M2, M3, P4, P5, M6, M7 }

; Compile error: a Scale and an Interval don't add.
let wrong = Major + P5

; OK: transpose the scale by a perfect fifth.
let correct = Major |> transpose P5

What you can build

Melodies with scale-degree references and intervals.
Chord progressions with functional harmony.
Multi-part arrangements with parts, sections and layers.
Algorithmic compositions using map, filter, fold and recursion.
Standard MIDI files ready for any DAW.

Ready to write one? Start with the Quick Start.

Listen-through example

The first half is a relative pitch idea; the second half changes the rhythmic density while keeping the same center.

rela

scale Major = { R, M2, M3, P4, P5, M6, M7 }

let question = | <1> <3> <5> <3> |:2
let answer   = | <6> <5> <3> <1> - <1> |:4

question ++ answer