93 lines
2.2 KiB
Markdown
93 lines
2.2 KiB
Markdown
# Lumen
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Lumen is a small dynamically-typed scripting language implemented in Kotlin. Source
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is scanned into tokens, parsed into an abstract syntax tree, compiled to a compact
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bytecode representation, and executed on a stack-based virtual machine.
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## Features
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- First-class functions and closures that capture mutable state
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- `let` / `var` bindings with lexical scoping
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- Control flow: `if` / `else`, `while`, and `for ... in` loops
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- Lists and maps with literal syntax and built-in methods
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- String, list, and map methods plus a small numeric standard library
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- A module system driven by `import` for splitting programs across files
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- Built-ins such as `print`, `println`, `len`, `type`, `str`, `int`, `assert`,
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`map`, `filter`, and `reduce`
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- An interactive REPL and a file runner
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## Building
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The project uses the Gradle wrapper, so no local Gradle install is required:
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```sh
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./gradlew build
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```
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## Running
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Start the REPL:
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```sh
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./gradlew run
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```
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Run a program file:
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```sh
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./gradlew run --args="examples/fib.lumen"
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```
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Disassemble the compiled bytecode for a file:
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```sh
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./gradlew run --args="--dump examples/fib.lumen"
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```
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## Example
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```lumen
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fn makeCounter() {
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var count = 0
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fn increment() {
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count = count + 1
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return count
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}
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return increment
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}
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let counter = makeCounter()
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println(counter(), counter(), counter())
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let numbers = [1, 2, 3, 4, 5]
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let doubled = map(fn(x) { return x * 2 }, numbers)
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println(doubled)
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```
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More programs live in [`examples/`](examples/), including a reverse-polish
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calculator, closures, sorting, CSV handling, and reusable library modules under
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`examples/lib/`.
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## Project layout
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```
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src/main/kotlin/lumen/
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lexer/ token definitions and the tokenizer
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ast/ abstract syntax tree nodes
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parser/ recursive descent parser
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bytecode/ opcodes, chunk container, and disassembler
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compiler/ AST to bytecode compiler
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runtime/ runtime value model
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vm/ virtual machine, builtins, methods, and standard library
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module/ module loader and import resolution
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cli/ REPL and command-line entry point
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src/test/kotlin/lumen/ test suite
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examples/ sample Lumen programs
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```
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## Tests
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```sh
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./gradlew test
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```
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