Docs Party 2024 (#15876)

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docs/src/extensions/developing-extensions.md

@@ -0,0 +1,104 @@
+# Developing Extensions
+
+## Extension Capabilities
+
+Extensions can add the following capabilities to Zed:
+
+- [Languages](./languages.md)
+- [Themes](./themes.md)
+
+## Directory Structure of a Zed Extension
+
+A Zed extension is a Git repository that contains an `extension.toml`. This file must contain some
+basic information about the extension:
+
+```toml
+id = "my-extension"
+name = "My extension"
+version = "0.0.1"
+schema_version = 1
+authors = ["Your Name <you@example.com>"]
+description = "My cool extension"
+repository = "https://github.com/your-name/my-zed-extension"
+```
+
+<!--
+TBD: Document `slash_commands`, `indexed_docs_providers` (see: extensions/gleam/extension.toml)
+-->
+
+In addition to this, there are several other optional files and directories that can be used to add functionality to a Zed extension. An example directory structure of an extension that provides all capabilities is as follows:
+
+```
+my-extension/
+  extension.toml
+  Cargo.toml
+  src/
+    lib.rs
+  languages/
+    config.toml
+    highlights.scm
+  themes/
+    my-theme.json
+```
+
+## WebAssembly
+
+Procedural parts of extensions are written in Rust and compiled to WebAssembly. To develop an extension that includes custom code, include a `Cargo.toml` like this:
+
+```toml
+[package]
+name = "my-extension"
+version = "0.0.1"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+zed_extension_api = "0.0.6"
+```
+
+Make sure to use the latest version of the [`zed_extension_api`](https://crates.io/crates/zed_extension_api) available on crates.io.
+
+In the `src/lib.rs` file in your Rust crate you will need to define a struct for your extension and implement the `Extension` trait, as well as use the `register_extension!` macro to register your extension:
+
+```rs
+use zed_extension_api as zed;
+
+struct MyExtension {
+    // ... state
+}
+
+impl zed::Extension for MyExtension {
+    // ...
+}
+
+zed::register_extension!(MyExtension);
+```
+
+## Developing an Extension Locally
+
+When developing an extension, you can use it in Zed without needing to publish it by installing it as a _dev extension_.
+
+From the extensions page, click the `Install Dev Extension` button and select the directory containing your extension.
+
+If you already have a published extension with the same name installed, your dev extension will override it.
+
+## Publishing your extension
+
+To publish an extension, open a PR to [this repo](https://github.com/zed-industries/extensions).
+
+In your PR, do the following:
+
+1. Add your extension as a Git submodule within the `extensions/` directory
+2. Add a new entry to the top-level `extensions.toml` file containing your extension:
+
+```toml
+[my-extension]
+submodule = "extensions/my-extension"
+version = "0.0.1"
+```
+
+3. Run `pnpm sort-extensions` to ensure `extensions.toml` and `.gitmodules` are sorted
+
+Once your PR is merged, the extension will be packaged and published to the Zed extension registry.