elmma
bdffe9e3c5
**Workspace 拆分** - aster-core: 纯库，zero-dependency，包含 lexer/parser/ast/interpreter/error/analysis - aster: REPL 二进制，薄封装 aster-core - aster-lsp: LSP 语言服务器 **VS Code 扩展 (vscode-ext/)** - TextMate 语法高亮 (.ast 文件) - 语言配置 (注释切换、括号配对、自动缩进) - LSP 客户端 (extension.js) **LSP 服务端功能** - Diagnostics: 实时显示 lex/parse 错误红色波浪线 - Completion: 关键字 + 内置函数 + 用户定义符号补全 - Hover: 悬停显示变量/函数信息 - Signature Help: 函数参数提示 - Goto Definition: Ctrl+Click 跳转到声明处 - Find References: 查找所有引用位置 - Rename: F2 重命名符号 **新增 analysis 模块** - collect_symbols: AST 遍历收集符号 - find_declaration/find_all_references: Token 扫描定位声明和引用
96 lines
4.9 KiB
Markdown
96 lines
4.9 KiB
Markdown
# CLAUDE.md
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This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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## Build & Run
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```bash
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# Build entire workspace
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cargo build
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# Run REPL (interactive)
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cargo run --bin aster
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# Execute a script file
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cargo run --bin aster -- aster-core/examples/script.ast
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# Run tests
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cargo test
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```
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This is a Rust workspace. `aster-core` is a pure-Rust library with no external dependencies (`edition = "2024"`).
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## Project structure
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```
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aster/
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├── Cargo.toml # workspace root (aster-core, aster, aster-lsp)
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├── aster-core/ # core library — lexer, parser, AST, interpreter
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├── aster/ # REPL binary (thin wrapper around aster-core)
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├── aster-lsp/ # LSP server (diagnostics, etc.)
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└── vscode-ext/ # VS Code extension (syntax highlighting + LSP client)
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```
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## VS Code Extension
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The `vscode-ext/` directory contains a VS Code extension that provides syntax highlighting and language server support for `.ast` files.
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### Install (development)
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```bash
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# 1. Build the LSP server
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cargo build --bin aster-lsp
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# 2. Install extension npm dependencies
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npm --prefix vscode-ext install
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# 3. Register the extension in VS Code
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# Windows: create junction
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powershell -Command "New-Item -ItemType Junction -Path '$env:USERPROFILE\.vscode\extensions\aster-lang' -Target '$PWD\vscode-ext' -Force"
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# macOS / Linux: symlink
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ln -s "$PWD/vscode-ext" "$HOME/.vscode/extensions/aster-lang"
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```
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After installation, reload VS Code (`Ctrl+Shift+P` → "Developer: Reload Window"). Open any `.ast` file — syntax errors will appear as red squiggly underlines.
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**Note:** The LSP server binary must be built (`cargo build --bin aster-lsp`) before the extension will work. After making changes to `aster-lsp`, rebuild and reload the VS Code window.
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## Architecture
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**Aster** is a tree-walking interpreter for a custom dynamically-typed scripting language. The pipeline follows the classic compiler frontend pattern:
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```
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Source text → Lexer → Tokens → Parser → AST → Interpreter → Output
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```
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### Module map (`aster-core/src/`)
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| Module | Responsibility |
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|---|---|
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| `lexer/` | Tokenizer. `Lexer::tokenize()` takes `&str` and returns `(Vec<Token>, Vec<RuntimeError>)`. Tokens carry `line`/`column` for error reporting. Supports `//` single-line and `/* */` block comments. |
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| `parser/` | Recursive-descent parser (Pratt-style for expressions). `Parser::parse()` returns `(Vec<Stmt>, Vec<RuntimeError>)`. Uses `synchronize()` for error recovery — skips to the next statement boundary on parse failure. |
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| `ast/` | AST node definitions. `Expr` (in `expr.rs`) covers literals, variables, assignment, property access/indexing, unary/binary/logical ops, calls, lambdas, and object/array literals. `Stmt` (in `stmt.rs`) covers let, expression stmts, blocks, if/while/for, functions, return/break/continue. |
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| `interpreter/` | Tree-walking evaluator. `Interpreter` holds an `env: Rc<RefCell<Env>>`. `Env` is a linked-list of scopes for lexical nesting. The `Signal` enum propagates `Return`/`Break`/`Continue` through the call stack. `builtins/` registers native functions (`print`, `input`, `clock`) organized as `io` and `os` modules (also available as global functions). |
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| `error/` | Three error variants: `LexError` (line+column), `ParseError` (token), `RuntimeError` (optional token). All implement `Display` and `std::error::Error`. |
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| `lib.rs` | Crate root — declares public modules, re-exports key types, provides `run_file()` and `run_repl()` convenience functions. |
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### Key design decisions
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- **`aster-core` has no external crate dependencies.** Everything is built on Rust's stdlib. `aster-lsp` depends on `lsp-server` + `lsp-types`.
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- **Rc<RefCell<>> for shared ownership.** `Env` chains, `Value::Object`, `Value::Array`, and `Value::Function` all use `Rc<RefCell<>>` for interior mutability — matching the dynamic, garbage-collected feel without a GC.
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- **Error-tolerant parsing.** Both lexer and parser collect errors into a `Vec` rather than failing on the first error, so multiple diagnostics can be reported per run.
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- **Closures capture by environment.** `Function` structs store the `Env` at definition time; lambda expressions (`fn(params) { body }`) work the same way.
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- **Compound assignment operators** (`+=`, `-=`, `*=`, `/=`, `%=`) are parsed into `Expr::Assign`/`Set`/`IndexSet` with an `AssignOp` variant and evaluated by `apply_assign_op`.
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### Language syntax overview
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Variables: `let x = 42;`
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Functions: `fn add(a, b) { return a + b; }`
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Closures: `fn(x, y) { return x + y; }`
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Control flow: `if`/`while`/`for` (C-style), `break`/`continue`, `return`
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Data: objects `{ key: val }`, arrays `[1, 2, 3]`, indexing `arr[i]`, property access `obj.prop`
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Operators: `+ - * / %`, `== != < > <= >=`, `&& || !`, `= += -= *= /= %=`
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Builtins: `print(...)`, `input(prompt?)`, `os.clock()` (also `clock()` directly)
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