mirror of
https://github.com/imjasonh/nescript
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b8c9e41276
README: project overview, quick start, feature list, example table LICENSE: MIT 4 new examples covering all language features: - arrays_and_functions: arrays, while loops, inline/regular functions - state_machine: multi-state flow with on enter/exit handlers - sprites_and_palettes: inline CHR data, palette switching, scroll, cast - mmc1_banked: MMC1 mapper, bank declarations, software multiply Parser fix: draw statement keyword-arg parsing now checks for ':' lookahead before consuming an identifier, preventing it from eating the next statement as a keyword argument (e.g., `i += 1` after a draw). https://claude.ai/code/session_01W6eQFStA66EuMKHUFo2rx3
117 lines
3.9 KiB
Markdown
117 lines
3.9 KiB
Markdown
# NEScript
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A statically-typed, compiled programming language for NES game development.
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NEScript compiles `.ne` source files directly into playable iNES ROM files, with no external assembler or linker dependencies. The compiler handles everything from source text to a ROM you can run in any NES emulator.
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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 an example
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cargo run -- build examples/hello_sprite.ne
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# Run the output ROM in an emulator
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# (produces examples/hello_sprite.nes)
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```
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## Hello World
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```
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game "Hello" {
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mapper: NROM
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}
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var px: u8 = 128
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var py: u8 = 120
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on frame {
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if button.right { px += 2 }
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if button.left { px -= 2 }
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if button.down { py += 2 }
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if button.up { py -= 2 }
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draw Smiley at: (px, py)
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}
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start Main
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```
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## Features
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- **Game-aware syntax** -- states, sprites, palettes, and input are first-class constructs
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- **Full type system** -- `u8`, `i8`, `u16`, `bool`, fixed-size arrays (`u8[N]`)
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- **Functions** -- with parameters, return types, `inline` hint, recursion detection
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- **State machines** -- `state` with `on enter`, `on exit`, `on frame` handlers
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- **Compile-time safety** -- call depth limits, recursion detection, type checking
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- **Optimizer** -- constant folding, dead code elimination, strength reduction
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- **Multiple mappers** -- NROM, MMC1, UxROM, MMC3
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- **Asset pipeline** -- PNG-to-CHR conversion, palette definitions, inline tile data
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- **Debug support** -- `--debug` flag, source maps, Mesen-compatible symbol export
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- **Single binary** -- no dependencies on ca65, Python, or any external tools
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## Documentation
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- **[Language Guide](docs/language-guide.md)** -- complete reference for every language feature
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- **[Architecture](docs/architecture.md)** -- compiler internals and module overview
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- **[NES Reference](docs/nes-reference.md)** -- hardware quick reference for contributors
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- **[Examples README](examples/README.md)** -- how to build and run examples
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## Examples
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| Example | Features demonstrated |
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|---------|---------------------|
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| [`hello_sprite.ne`](examples/hello_sprite.ne) | D-pad input, sprite drawing |
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| [`bouncing_ball.ne`](examples/bouncing_ball.ne) | Automatic movement, edge detection |
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| [`coin_cavern.ne`](examples/coin_cavern.ne) | Multi-state game, functions, constants, gravity |
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| [`arrays_and_functions.ne`](examples/arrays_and_functions.ne) | Arrays, functions, while loops, inline functions |
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| [`state_machine.ne`](examples/state_machine.ne) | State transitions, on enter/exit, timers |
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| [`sprites_and_palettes.ne`](examples/sprites_and_palettes.ne) | Inline CHR data, palettes, scroll, type casting |
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| [`mmc1_banked.ne`](examples/mmc1_banked.ne) | MMC1 mapper, bank declarations, multiply |
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## Compiler Commands
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```bash
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# Compile to ROM
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nescript build game.ne
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# Compile with custom output path
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nescript build game.ne --output my_game.nes
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# Type-check only (no ROM output)
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nescript check game.ne
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# View generated 6502 assembly
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nescript build game.ne --asm-dump
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# Enable debug mode
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nescript build game.ne --debug
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```
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## Emulator Compatibility
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Output ROMs are standard iNES format and work with any NES emulator:
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- **[Mesen](https://www.mesen.ca/)** -- recommended, best debugging support
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- **[FCEUX](https://fceux.com/)**
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- **[Nestopia](http://nestopia.sourceforge.net/)**
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## Project Status
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NEScript implements all five planned milestones:
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| Milestone | Status | Key Features |
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|-----------|--------|-------------|
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| M1: Hello Sprite | Done | Full compiler pipeline, assembler, ROM builder |
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| M2: Game Loop | Done | Functions, arrays, IR, optimizer, call graph analysis |
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| M3: Asset Pipeline | Done | PNG-to-CHR, sprites, palettes, debug symbols |
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| M4: Optimization | Done | Strength reduction, ZP promotion, type casting, asm-dump |
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| M5: Bank Switching | Done | MMC1/UxROM/MMC3, bank declarations, software mul/div |
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210 tests across 14 modules, with CI running fmt, clippy, test, and example compilation on every push.
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## License
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[MIT](LICENSE)
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