mirror of
https://github.com/imjasonh/nescript
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7294ae3efa
Struct field types beyond the v1 scalar set (`u8`, `i8`, `u16`,
`bool`) used to error out with `E0201: struct fields must be
u8/i8/u16/bool`. The size accumulator already handled them
correctly — what was missing was: (1) the analyzer side that
synthesizes per-leaf symbols and allocations for nested structs
plus a single array-typed symbol for array fields, (2) the
parser's chained-field-access path, and (3) the IR-lowering
recursion through nested struct literal initializers and array
literal field values.
The synthetic-variable model carries through unchanged: a
`var p: Player` where `Player { pos: Vec2, hp: u8, inv: u8[4] }`
and `Vec2 { x: u8, y: u8 }` produces flat allocations for
`p.pos.x`, `p.pos.y`, `p.hp`, and `p.inv`, plus an intermediate
`p.pos` Struct symbol so dotted-name lookups still resolve. Array
fields get a single allocation with the array type so the
existing `Expr::ArrayIndex` lowering path handles `p.inv[i]`
without changes. Array-of-structs is still rejected with E0201
because the synthetic model can't index per-element layouts
without further codegen work.
The parser change is the only structural move: `parse_primary`
and `parse_assign_or_call` now loop the dot chain into a single
joined identifier so `p.pos.x` becomes `FieldAccess("p.pos", "x")`
and `p.inv[0]` becomes `ArrayIndex("p.inv", 0)`. The downstream
analyzer and IR lowering use the same `format!("{name}.{field}")`
join they already used for one-level access — no plumbing
changes required.
Includes a new `examples/nested_structs.ne` that exercises both
features end-to-end with two `Hero` instances carrying nested
positions and inventory arrays. The reproducibility tripwire
ROM is committed alongside it and the emulator harness has a
matching pair of golden files.
https://claude.ai/code/session_01KEczoNUX3WmcFLfq6iAQxB
78 lines
4.1 KiB
Markdown
78 lines
4.1 KiB
Markdown
# NEScript Examples
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## Quick Start
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```bash
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# Build the compiler
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cargo build --release
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# Compile all examples
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for f in examples/*.ne; do cargo run -- build "$f"; done
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# Or compile one
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cargo run -- build examples/hello_sprite.ne
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```
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Open any `.nes` file in an NES emulator ([Mesen](https://www.mesen.ca/), [FCEUX](https://fceux.com/), etc.)
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## Examples
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| File | Features | Description |
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|------|----------|-------------|
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| `hello_sprite.ne` | input, draw | Move a sprite with the d-pad |
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| `bouncing_ball.ne` | if/else, variables | Auto-bouncing sprite with edge detection |
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| `coin_cavern.ne` | states, functions, constants | 3-state game with gravity and coin collection |
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| `arrays_and_functions.ne` | arrays, functions, while | Enemy array with collision detection |
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| `state_machine.ne` | on enter/exit, transitions | Multi-state flow with timers |
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| `sprites_and_palettes.ne` | sprites, scroll, cast | Inline CHR data, PPU scroll writes, type casting |
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| `mmc1_banked.ne` | MMC1, banks, multiply | Banked mapper with software multiply |
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| `uxrom_user_banked.ne` | UxROM, `bank Foo { fun ... }`, cross-bank trampoline | First example to put real user code inside a switchable bank. The animation step lives in `bank Extras` and is invoked from the fixed-bank state handler via a generated `__tramp_step_animation` stub that selects bank 0, JSRs the body, then restores the fixed bank before returning. |
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| `palette_and_background.ne` | palette, background, set_palette, load_background | Reset-time initial load plus vblank-safe runtime swaps |
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| `friendly_assets.ne` | named colours, grouped palette, pixel art, tilemap+legend, palette_map, scalar sfx pitch, note-name music | Exercises every "friendlier" asset syntax at once — the `palette` uses `bg0..sp3` + a shared `universal:`, the sprite is authored as ASCII pixel art, the background uses a `legend { ... } + map:` tilemap with a `palette_map:` for attributes, the sfx uses a scalar `pitch:` + `envelope:` alias, and the music uses note names (`C4, E4 40, rest 10`) with a `tempo:` default. |
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| `noise_triangle_sfx.ne` | `channel: noise`, `channel: triangle` on `sfx` blocks | Demonstrates the noise and triangle sfx channels. Declares one noise burst and one triangle bass note, plays each on a timer so the emulator harness captures both the pixel output and the APU state. |
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| `nested_structs.ne` | nested struct fields, array struct fields, chained literals | Two `Hero` instances each carry a `Vec2` position and a `u8[4]` inventory. Exercises `hero.pos.x` chained access, `hero.inv[i]` array-field access, and chained struct-literal initializers (`Hero { pos: Vec2 { x: ..., y: ... }, inv: [...] }`). |
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| `platformer.ne` | **every subsystem** | End-to-end side-scrolling demo: custom CHR tileset, full 32×30 nametable with per-region attribute palettes, 2×2 metasprite hero with gravity/jump physics, wrap-around horizontal scrolling, stomp-or-die enemy collisions with a live stomp-count HUD, coin pickups, user-declared SFX + music, and a Title → Playing → GameOver state machine with a proximity-based autopilot so the headless harness cycles through stomp, stomp, die, and retry inside six seconds. Regenerate the tile art with `cargo run --bin gen_platformer_tiles`. |
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## Emulator Controls
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| NES Button | Typical Key |
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|------------|-------------|
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| D-pad | Arrow keys |
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| A | Z |
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| B | X |
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| Start | Enter |
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| Select | Right Shift |
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## About Sprites
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Sprite names in `draw Player at: (x, y)` are parsed and recorded in the AST.
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You can define sprites with inline CHR tile data:
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```
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sprite Player {
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chr: [0x3C, 0x42, 0x81, 0x81, 0x81, 0x81, 0x42, 0x3C,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
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}
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```
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If no matching sprite declaration exists, the draw uses the built-in default
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tile (a smiley face). See `sprites_and_palettes.ne` for a full example.
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## Compiler Commands
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```bash
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# Compile to ROM
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cargo run -- build game.ne
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# Custom output path
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cargo run -- build game.ne --output my_game.nes
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# Type-check only
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cargo run -- check game.ne
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# View generated 6502 assembly
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cargo run -- build game.ne --asm-dump
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# Debug mode
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cargo run -- build game.ne --debug
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```
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