plyn

plyn is an editor extension for ***plain, a spec-driven programming language developed and maintained by *codeplain. It supports VS Code, Cursor, and Zed.

It adds first-class language support for ***plain, so you can edit, navigate, and refactor ***plain code with confidence.

Features

The extension implements:

• Syntax highlighting that follows the ***plain specification and highlights keywords, types, literals, comments, and operators for clear readability.
• Rename concept support that lets you safely rename a concept across the workspace, keeping definitions and references in sync.
• Go to definition and go to references so you can jump to where a concept is declared and see where it is used.
• Hover that shows where a concept is defined and where it is used across the workspace.
• Diagnostics for ***definitions*** syntax, unknown/misspelled section headers (with "did you mean" hints), and unused, undefined, cyclic, and duplicately-defined concepts.
• Section folding to collapse a whole ***section*** (definitions, test reqs, functional specs, …) down to its header.
• Plain file icon theme to make .plain files easy to spot in the explorer.

Installation

plyn is published to the Open VSX Registry.

• VS Code / Cursor: open the Extensions view and search for plyn (Codeplain.plyn).
• From a .vsix: download the latest release artifact and install it with code --install-extension plyn-<version>.vsix (or cursor --install-extension ...), or via the Extensions view → "Install from VSIX…".
• Zed: the Zed extension lives in the zed/ directory. Install it via Zed → Extensions → "Install Dev Extension…" and select the zed/ folder.
  • Section folding in Zed is opt-in: Zed only folds via the language server when you enable it. Add this to your Zed settings.json (VS Code / Cursor need no setup — folding works out of the box there):

    "languages": { "***plain": { "document_folding_ranges": "on" } }
    

Usage

• Open any .plain file to activate the language features and syntax highlighting.
• Use F12 for Go to Definition and Shift+F12 for Go to References.
• Hover over a concept to see where it is defined and used.
• Use F2 to rename a concept across the project. The extension updates all matching references for you.

Release Notes

0.0.2

Adds diagnostics (definitions syntax; unused, undefined with "did you mean", cyclic, and duplicate concepts; unknown/misspelled section headers; ***acceptance tests*** placement; built-in capitalization), built-in concepts (:Implementation:, :ConformanceTests:, :AcceptanceTests:, :UnitTests:) with hover descriptions, and section folding. Fixes indexing of concepts used only on indented lines, and stops a concept's own declaration from being listed as one of its usages.

0.0.1

Initial release of plyn: syntax highlighting for ***plain, concept-aware Go to Definition / References, hover, workspace-wide rename, and a plain file icon theme.