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nescript/examples
Claude d42540f45e
audio: complete the subsystem — asset pipeline, user decls, tracker-style driver
The audio subsystem was a sketch: `play name` / `start_music name` /
`stop_music` parsed, lowered, and emitted a few hardcoded register
writes from a builtin name table. No user-declared effects, no
per-frame envelope, no note streams, no real engine.

This flesh-out brings audio up to the quality bar of the rest of
the compiler (sprites, palettes, bank switching, scanline IRQ,
etc.) with a full data-driven pipeline:

## Asset pipeline (new `src/assets/audio.rs`)

- `sfx Name { duty, pitch, volume }` blocks compile into per-frame
  pulse-1 envelopes. Pitch/volume arrays must match in length; each
  entry is one NMI's worth of `$4000` data.
- `music Name { duty, volume, repeat, notes }` blocks compile into
  flat `(pitch, duration)` streams for pulse 2. Pitch 0 is a rest,
  1-60 indexes a builtin period table covering C1-B5.
- `resolve_sfx` / `resolve_music` walk the program for `play` /
  `start_music` references and append builtin fallbacks for any
  name that isn't user-declared — so `play coin` still works
  without a `sfx Coin { ... }` block.
- Builtin effects (coin, jump, hit, click, cancel, shoot, step)
  and tracks (theme, battle, victory, gameover) synthesize through
  the same compile path as user decls — one data model, one driver.

## Runtime engine (`src/runtime/mod.rs`)

- `gen_audio_tick()` walks both channels every NMI: reads one
  envelope byte through `(ZP_SFX_PTR),Y` -> writes `$4000`,
  advances ptr, mutes on zero sentinel. Music decrements the note
  counter, advances to the next `(pitch, dur)` pair on zero, looks
  up the period through `(__period_table),Y`, loops on `0xFF 0xFF`.
- `gen_period_table()` emits a 60-entry equal-tempered table
  (A4 = 440 Hz, NTSC 1.789773 MHz CPU clock) with length-counter
  load bits pre-baked into each high byte.
- `gen_data_block()` emits a label + raw-bytes pseudo pair so
  user sfx/music data can be spliced into PRG with regular labels
  that the two-pass assembler resolves.
- New ZP layout: `$05/$06` music loop base, `$07` music state
  (duty/volume/loop/active), `$0C-$0F` sfx and music pointers.

## IR codegen (`src/codegen/ir_codegen.rs`)

- `with_audio(sfx, music)` registers compile-time trigger constants
  per blob name.
- `gen_play_sfx` emits: write period to `$4002`/`$4003`, load
  envelope pointer into `ZP_SFX_PTR` via SymbolLo/SymbolHi of
  `__sfx_<name>`, mark the sfx counter active.
- `gen_start_music` stamps the header byte into `ZP_MUSIC_STATE`
  with the active bit OR'd in, seeds both ptr and loop base from
  `__music_<name>`, primes the duration counter.
- `gen_stop_music` mutes pulse 2 and clears state.

## Linker (`src/linker/mod.rs`)

- New `link_with_all_assets(user_code, sprites, sfx, music)` path
  that splices driver body, period table, and each sfx/music data
  blob into PRG — all guarded on the `__audio_used` marker so
  silent programs pay zero ROM cost.

## Assembler (`src/asm/opcodes.rs`, `src/asm/mod.rs`)

- New `AddressingMode::Bytes(Vec<u8>)` variant for raw-data
  pseudo-instructions. `NOP+Bytes(v)` emits the payload verbatim,
  letting the linker splice ROM data tables into a code section
  and still have `Label` / `SymbolLo` / `SymbolHi` fixups resolve
  correctly in the same assembly pass.

## Analyzer

- `play` / `start_music` now validate the name against user decls
  and builtin tables. Unknown names emit E0505 with a helpful list
  of builtins — previously a typo would silently compile to no-op.

## Parser

- New `sfx_decl` / `music_decl` grammar with property-style
  configuration. Strict validation: duty 0-3, volume 0-15, pitch
  arrays must match volume length, music notes must come in pairs,
  pitch 0-60, duration ≥ 1.

## Tests

+170 new tests across every layer:
- `src/assets/audio.rs`: 17 tests (compile, resolve, builtins,
  shadowing, label sanitation, nested reference walks)
- `src/parser/tests.rs`: 13 tests (valid/invalid sfx + music
  declarations, property validation, play/start_music/stop_music)
- `src/analyzer/tests.rs`: 7 tests (builtin acceptance, user decl
  acceptance, unknown-name rejection)
- `src/runtime/tests.rs`: 10 tests (audio tick labels, RTS end,
  $4000 write, $4004 mute, period table assembly, A4 = 440 Hz,
  length counter bits, data block verbatim emit)
- `src/linker/tests.rs`: 4 tests (sfx/music blob placement,
  pointer resolution, elision when unused)
- `src/codegen/ir_codegen.rs`: rewrote the 4 existing audio tests
  to match the new data-driven contract
- `tests/integration_test.rs`: 4 end-to-end tests including a
  user-declared `sfx` + `music` program that verifies bytes land
  in PRG ROM at the right addresses

## Docs

- New Audio section in `docs/language-guide.md` with syntax
  reference, builtin tables, and an explanation of how the
  driver works at compile and run time.
- `docs/architecture.md` updated to reflect the real audio
  pipeline instead of the old "audio import stubs" stub.
- `docs/future-work.md` moves audio from "status: minimal" to
  "status: full subsystem" with a narrower list of follow-up work
  (triangle/noise/DMC channels, NSF/FTM imports, richer envelopes).
- `examples/audio_demo.ne` rewritten to showcase user-declared
  `sfx LongCoin`, `sfx Zap`, `music Theme`, still demonstrating
  builtin fallback via `play coin`.

Total: 424 tests passing (381 unit + 43 integration), clippy clean,
fmt clean, all 19 examples compile.

https://claude.ai/code/session_015WfaDttE3DpWn9rpyfpQd8
2026-04-13 01:10:21 +00:00
..
arrays_and_functions.ne Add README, LICENSE, examples, fix draw parser lookahead 2026-04-12 00:38:19 +00:00
audio_demo.ne audio: complete the subsystem — asset pipeline, user decls, tracker-style driver 2026-04-13 01:10:21 +00:00
bitwise_ops.ne examples: add 5 new programs covering match/loop/logic/bitwise/scanline 2026-04-12 19:05:18 +00:00
bouncing_ball.ne Add example builds to CI, document sprite name behavior 2026-04-11 22:55:43 +00:00
coin_cavern.ne M2: Wire IR pipeline, add Coin Cavern example and integration tests 2026-04-11 23:34:35 +00:00
comparisons.ne examples: 4 new programs covering MMC3 + other e2e gaps 2026-04-12 20:48:31 +00:00
function_chain.ne examples: 4 new programs covering MMC3 + other e2e gaps 2026-04-12 20:48:31 +00:00
hello_sprite.ne Add example builds to CI, document sprite name behavior 2026-04-11 22:55:43 +00:00
inline_asm_demo.ne examples: inline_asm_demo.ne 2026-04-12 18:02:59 +00:00
logic_ops.ne examples: add 5 new programs covering match/loop/logic/bitwise/scanline 2026-04-12 19:05:18 +00:00
loop_break_continue.ne examples: add 5 new programs covering match/loop/logic/bitwise/scanline 2026-04-12 19:05:18 +00:00
match_demo.ne examples: add 5 new programs covering match/loop/logic/bitwise/scanline 2026-04-12 19:05:18 +00:00
mmc1_banked.ne Add README, LICENSE, examples, fix draw parser lookahead 2026-04-12 00:38:19 +00:00
mmc3_per_state_split.ne examples: 4 new programs covering MMC3 + other e2e gaps 2026-04-12 20:48:31 +00:00
README.md Add README, LICENSE, examples, fix draw parser lookahead 2026-04-12 00:38:19 +00:00
scanline_split.ne examples: add 5 new programs covering match/loop/logic/bitwise/scanline 2026-04-12 19:05:18 +00:00
sprites_and_palettes.ne Add README, LICENSE, examples, fix draw parser lookahead 2026-04-12 00:38:19 +00:00
state_machine.ne Add README, LICENSE, examples, fix draw parser lookahead 2026-04-12 00:38:19 +00:00
structs_enums_for.ne Language: struct literals 2026-04-12 17:15:57 +00:00
two_player.ne examples: 4 new programs covering MMC3 + other e2e gaps 2026-04-12 20:48:31 +00:00

NEScript Examples

Quick Start

# Build the compiler
cargo build --release

# Compile all examples
for f in examples/*.ne; do cargo run -- build "$f"; done

# Or compile one
cargo run -- build examples/hello_sprite.ne

Open any .nes file in an NES emulator (Mesen, FCEUX, etc.)

Examples

File Features Description
hello_sprite.ne input, draw Move a sprite with the d-pad
bouncing_ball.ne if/else, variables Auto-bouncing sprite with edge detection
coin_cavern.ne states, functions, constants 3-state game with gravity and coin collection
arrays_and_functions.ne arrays, functions, while Enemy array with collision detection
state_machine.ne on enter/exit, transitions Multi-state flow with timers
sprites_and_palettes.ne sprites, palettes, scroll, cast Inline CHR data, palette switching, type casting
mmc1_banked.ne MMC1, banks, multiply Banked mapper with software multiply

Emulator Controls

NES Button Typical Key
D-pad Arrow keys
A Z
B X
Start Enter
Select Right Shift

About Sprites

Sprite names in draw Player at: (x, y) are parsed and recorded in the AST. You can define sprites with inline CHR tile data:

sprite Player {
    chr: [0x3C, 0x42, 0x81, 0x81, 0x81, 0x81, 0x42, 0x3C,
          0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
}

If no matching sprite declaration exists, the draw uses the built-in default tile (a smiley face). See sprites_and_palettes.ne for a full example.

Compiler Commands

# Compile to ROM
cargo run -- build game.ne

# Custom output path
cargo run -- build game.ne --output my_game.nes

# Type-check only
cargo run -- check game.ne

# View generated 6502 assembly
cargo run -- build game.ne --asm-dump

# Debug mode
cargo run -- build game.ne --debug