Wolfgang (Amadeus Language)

Compose complete musical pieces in readable text, then export to MIDI or sheet music.

Wolfgang is a functional music DSL with an approachable text notation called Amadeus. Write melodies, chords, and structure with simple words; combine and transform ideas compositionally; output to DAWs via MIDI and to notation formats like SVG, LilyPond, and MusicXML.

Why Wolfgang

• Readable notation: Write music like "C4 quarter", "Cmaj half", "rest eighth".
• Composable: Build phrases, repeat, and transform (transpose, invert, retrograde) using functional ideas.
• Multiple outputs: Export to MIDI for DAWs and to sheet music formats for engraving and sharing.
• Hackable: Pure Haskell core with clear modules for Core, MIDI, Sheet, Parser, and Theory.

Quickstart

1. Build and run

stack setup && stack build
stack run

2. Compose a file to MIDI

# Create a file
cat > twinkle_star.amadeus <<'EOF'
# Twinkle (excerpt)
C4 quarter
C4 quarter
G4 quarter
G4 quarter
A4 quarter
A4 quarter
G4 half

Cmaj quarter
Fmaj quarter
Gmaj quarter
Cmaj half
EOF

# Compile to MIDI
stack run -- compose twinkle_star.amadeus
# => twinkle_star.mid

3. Try the REPL

stack run -- --repl
# wolfgang> :play C4 quarter
# wolfgang> :save demo.mid Cmaj half

What you can write today (Amadeus essentials)

Amadeus favors clear words over symbols. The implemented subset supports:

• Notes: C4 quarter, F#5 half
• Rests: rest eighth, rest quarter
• Named chords: Cmaj whole, Dmin half
• Scales: scale C major, scale D minor
• Directives: tempo 96, timesig 3/4, key G major, pickup quarter
• Assignments: theme = C4 quarter (assign a name to reuse later)

Durations include names and shorthands: whole|half|quarter|eighth|sixteenth and w|h|q|e|s, plus dotted and triplet shorthands in the core library.

Planned/partially implemented (see Grammar and modules):

• Sequences and parallel blocks: seq [ ... ], par [ ... ], bar-delimited |
• Chords by explicit notes: chord [C4,E4,G4] half
• Transforms: transpose n, invert PIVOT, retrograde, augment r, diminish r
• Articulations and dynamics: staccato, legato, mf, ff etc.

Refer to docs/GRAMMAR.md for the full EBNF and examples; the parser is being expanded to match the full spec.

CLI usage

wolfgang                      -- Run default example
wolfgang --example NAME       -- Run named example (scale|chords|canon|variations)
wolfgang --sheet-example NAME -- Sheet examples (simple|progression|classical|demo)
wolfgang --repl               -- Start interactive REPL
wolfgang compose FILE.amadeus -- Compile .amadeus to MIDI (.mid)
wolfgang sheet FILE.amadeus [svg|lilypond|musicxml|png]

Notes on sheet export:

• MIDI export uses your .amadeus content today.
• Sheet export support (SVG, LilyPond, MusicXML, PNG) is available via the API and CLI examples; the end-to-end Amadeus→Sheet pipeline is in progress and will broaden coverage as the parser expands.

Minimal examples

Single line melody

C4 quarter
D4 quarter
E4 quarter
F4 quarter
G4 half

Directive + scale + rest + chord

tempo 96
timesig 3/4
key G major

scale C major
rest quarter
Cmaj half

Output formats

• MIDI (.mid): Import into Logic Pro, Ableton Live, Cubase, FL Studio, etc.
• SVG (sheet): Viewable in browsers; great for docs and the web.
• LilyPond (.ly): Professional engraving. Compile with lilypond file.ly.
• MusicXML (.xml): Import into MuseScore, Finale, Dorico, Sibelius.
• PNG: Quick shareable images (requires LilyPond when using that backend).

Project layout (high-level)

• src/Wolfgang/Core/*: Core types for Pitch, Duration, Music, combinators.
• src/Wolfgang/Parser/*: Amadeus grammar and parser.
• src/Wolfgang/MIDI/*: MIDI types, compiler, and file writer.
• src/Wolfgang/Sheet/*: Sheet music model, compiler, and exporters.
• docs/: Design notes, grammar, testing guidance.
• examples/: Example .amadeus files and Haskell demos.

REPL cheatsheet

• Commands: :help, :quit, :play EXPR, :save FILE EXPR
• Try: :play C4 quarter, :save chords.mid Cmaj whole

Development

• Build: stack build
• Run examples: stack run -- --example scale
• Tests: stack test or ./run-tests.sh

Status

Active development. MIDI export is stable for the implemented subset. The Amadeus parser and sheet export are expanding rapidly toward the full grammar in docs/GRAMMAR.md.

License

MIT