Features

Feature	Description
🎨 Semantic Highlighting	Lexer-accurate token colors from the Language Server (v2) — keywords, functions, classes, types — layered over TextMate so English words are colored only where they're truly keywords, never inside strings or comments
🧩 Embedded Languages	Full HTML/CSS/JS highlighting inside triple-quoted strings (`""" … """`) and SQL highlighting inside query strings — so the web markup, styles, scripts, and queries embedded in EPL apps are colored, not flat
🔤 String Interpolation	`$name` and `${expr}` inside strings are highlighted with correct EPL syntax — a literal `$` that isn't a template is left untouched, exactly as the language treats it
🔍 Real-time Diagnostics	Error detection powered by EPL's Language Server Protocol
💡 Code Completion	725+ stdlib function signatures with documentation
📖 Hover Documentation	Function signatures, parameter types, and descriptions on hover
✏️ Token-aware Rename	Safe workspace rename (`F2`) that only touches real identifiers — never matches inside strings or comments
🔗 Find References	Token-aware find-all-references across the workspace
▶️ Run from Editor	Execute `.epl` files directly with `Ctrl+Shift+R`
⚡ Bytecode VM Backend	Run with the bytecode VM (the default `epl run` engine) — verified parity with the interpreter, including real closures / capturing lambdas as of v10.1.0
🔧 Type Checking	Static type analysis via `epl check`
📐 Formatting	Auto-format EPL source files
🧪 Linting	Code quality analysis
📊 Profiling	Performance profiling from the editor
👀 Watch Mode	Re-run on save, with configurable per-run timeout
⚡ Error Diagnostics	`epl fix` with Rust-style context window, 55+ offline patterns, `--fix` auto-correction
🩺 Doctor	Environment health check (`epl doctor`)

Prerequisites

pip install eplang

The extension requires the epl CLI on your system PATH. If it's not found automatically, set epl.lsp.path in VS Code settings.

Commands

Command	Shortcut	Description
`EPL: Run Current File`	`Ctrl+Shift+R`	Run the active `.epl` file in the terminal
`EPL: Run Current File with Bytecode VM`	—	Execute via the bytecode VM (`epl vm`)
`EPL: Type Check Current File`	`Ctrl+Shift+K`	Run EPL's static type checker
`EPL: Format Current File`	—	Format using the EPL formatter
`EPL: Build Current File`	—	Compile to native executable
`EPL: Lint Current File`	—	Lint for code quality issues
`EPL: Profile Current File`	—	Profile execution performance
`EPL: Watch Current File`	—	Re-run on save
`EPL: Serve Current File`	—	Start production web server
`EPL: Deploy Current File`	—	Generate deployment configs (k8s/aws/gcp/azure/docker)
`EPL: Fix Errors`	—	Error diagnostics with 55+ offline patterns and auto-fix
`EPL: Run Doctor`	—	Environment health check

Settings

Setting	Default	Description
`epl.lsp.enabled`	`true`	Enable the Language Server for diagnostics and completions
`epl.lsp.path`	`"epl"`	Path to the `epl` CLI binary
`epl.strictMode`	`false`	Enable strict type checking mode
`epl.serve.port`	`8000`	Default port for `epl serve`
`epl.serve.observability`	`false`	Auto-attach `/_health`, `/_ready`, `/_metrics` endpoints
`epl.watch.timeout`	`""`	Per-run timeout for `epl watch` (seconds, or `none`). Empty = use CLI default (uncapped since v9.0.0).

Architecture

VS Code Extension (TypeScript)
        │
        ▼
  LSP Client (vscode-languageclient)
        │
        ▼ stdin/stdout
  EPL Language Server (Python)
  └── epl/lsp_server.py
      ├── Diagnostics (real-time error detection)
      ├── Completions (keyword + stdlib suggestions)
      ├── Hover (function signatures + docs)
      └── Formatting (epl/formatter.py)

Troubleshooting

Issue	Solution
`epl` command not found	Install EPL: `pip install eplang`, then restart VS Code
LSP not starting	Check `epl.lsp.path` setting; verify `epl lsp` runs in terminal
No syntax highlighting	Ensure file extension is `.epl`
Diagnostics not updating	Restart the Language Server: `Ctrl+Shift+P` → "Developer: Restart Extension Host"

Building from Source

cd vscode-extension
npm install
npx @vscode/vsce package

This creates a .vsix file you can install via Extensions: Install from VSIX... in VS Code.

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