Editor Support

Sema has editor plugins for VS Code, Zed, IntelliJ IDEA, Neovim, Vim, Emacs, Helix, and Sublime Text. Each plugin lives in its own repository under the sema-lisp GitHub org and is published to that editor's registry.

Every plugin provides syntax highlighting for the full standard library, special forms, keyword and character literals, strings, numbers, comments, and LLM primitives. Most also wire up Sema's built-in developer tooling, which ships inside the sema binary:

Language Server (LSP) (sema lsp) — diagnostics, completion, hover, go-to-definition, references, rename, and code lenses.
Debugger (DAP) (sema dap) — breakpoints, stepping, stack traces, and variable inspection.
MCP server (sema mcp) — exposes Sema's tools (eval, build, notebook, docs) to editor AI agents.

Editor	Repo	LSP	DAP	MCP	Highlighting
VS Code	`vscode-sema`	✓	✓	✓	TextMate
Zed	`zed-sema`	✓	✓	✓	tree-sitter
IntelliJ	`intellij-sema`	✓	✓	—	own lexer
Neovim	`sema.nvim`	✓	✓*	—	tree-sitter
Vim	`sema.vim`	—	—	—	Vimscript
Emacs	`emacs-sema`	✓	—	—	font-lock
Helix	`helix-sema`	✓	✓	—	tree-sitter
Sublime Text	`sublime-sema`	✓†	—	—	native syntax

* Neovim DAP requires nvim-dap. † Sublime LSP requires the LSP package.

The features that shell out to sema (LSP, DAP, MCP, run/format) need the sema binary on your PATH — install it from sema-lang.com. Syntax highlighting and structural editing work without it.

VS Code

TextMate-grammar highlighting plus a full LSP client, a debug adapter that runs sema dap, an embedded notebook editor, and the Sema MCP server.

Install

From the VS Marketplace (VS Code) or Open VSX (VSCodium, Cursor, Windsurf, Gitpod, …):

ext install sema-lang.sema-lang

Or open the Extensions view (Cmd+Shift+X / Ctrl+Shift+X) and search for Sema Lisp. Point the extension at a specific binary with the sema.path setting if sema isn't on your PATH.

Features

Syntax highlighting (special forms, builtins, LLM primitives, keywords, strings, numbers, regex/f-string literals)
Bracket matching, auto-closing, and surrounding pairs for (), [], {}, ""
Comment toggling (Cmd+/ / Ctrl+/) and s-expression-aware indentation
File icons for .sema and .sema-nb
Language server — completions, hover, go-to-definition, references, rename, signature help, diagnostics, document symbols, and inline eval results
Debugging — line/conditional breakpoints, step in/over/out, stack traces, variable and upvalue inspection, evaluate-on-hover, and an "Uncaught Exceptions" filter
Notebooks — open a .sema-nb file to edit it in the embedded notebook UI with live cell execution
MCP server — registers sema mcp in the Chat / agent view

Zed

Extension built on the shared tree-sitter-sema grammar, with LSP, DAP, runnables, and the Sema MCP context server.

Install

From inside Zed: Cmd+Shift+P → zed: extensions → search for Sema → Install. The grammar is fetched automatically at the commit pinned in extension.toml — no manual grammar setup.

To hack on it locally, clone zed-sema and use zed: install dev extension.

Features

Syntax highlighting, ; line and #| … |# block comments (with TODO/FIXME injection), auto-pairs, and bracket matching
Code outline for top-level definitions and block forms
2-space auto-indent; Vim text objects (af/if for functions, ac/ic for agents/tools)
Runnables — a gutter ▶ to run the file or evaluate the selected form (see note below)
Language server and debugging via sema lsp / sema dap
MCP server — registers sema mcp with Zed's agent panel
Secret redaction for llm/configure/llm/define-provider/llm/auto-configure arguments during screen sharing

Runnables need a one-time task

Zed doesn't let an extension bundle the task its ▶ button runs. Add it once via zed: open tasks (see the repo README for the tasks.json snippet).

IntelliJ IDEA

Full IDE support via LSP4IJ connecting to the Sema language server, plus a native debugger, notebook editor, and run configurations.

Requirements

IntelliJ IDEA 2024.3+ (or any JetBrains IDE on build 243+)
LSP4IJ — installed automatically as a plugin dependency
The sema binary on PATH, or set it under Settings → Languages & Frameworks → Sema

Install

From the IDE: Settings → Plugins → Marketplace, search for Sema. To build from source instead:

bash

git clone https://github.com/sema-lisp/intellij-sema
cd intellij-sema
./gradlew buildPlugin
# Then: Settings → Plugins → ⚙️ → Install Plugin from Disk…
# and pick build/distributions/Sema-<version>.zip

Features

Syntax highlighting for .sema, .semac, and .sema-nb, with a configurable color settings page
LSP (via LSP4IJ) — completion, hover, go-to-definition, references, rename, diagnostics, folding, inlay hints, document highlight, semantic tokens, call hierarchy, and clickable import/load links
Code lenses — evaluate top-level forms inline, plus a "Clear Sema Results" action
Debugging — breakpoints, continue, step over/into/out, stack frames, scopes, and variable inspection
Notebook editor for .sema-nb — live cell evaluation in a JCEF view, run-all, open-in-browser, export to Markdown
Reformat Code, brace matching, ()/[]/{} auto-pairing, line/block commenting, Extend/Shrink Selection
Run configurations, custom file icons, and a configurable binary location

Neovim

Tree-sitter highlighting via nvim-treesitter, with a zero-config language server and optional DAP.

Install

With lazy.nvim:

lua

{
  "sema-lisp/sema.nvim",
  ft = "sema",
  dependencies = { "nvim-treesitter/nvim-treesitter" },
}

With packer.nvim:

lua

use({ "sema-lisp/sema.nvim", requires = { "nvim-treesitter/nvim-treesitter" } })

Then run :TSInstall sema once to fetch and compile the pinned tree-sitter-sema grammar.

Features

Filetype detection for .sema
Tree-sitter highlighting (registers the parser + ships highlight queries)
Language server (automatic) — on Neovim ≥ 0.11 the plugin registers and enables sema lsp with no config (falls back to a FileType autocmd on older versions); no nvim-lspconfig needed
Debugging (optional) — if nvim-dap is installed, registers the sema dap adapter with a "Launch Sema file" configuration

Vim

Pure Vimscript plugin — syntax highlighting, filetype detection, and Lisp-aware editing with no runtime dependencies. Works in both Vim and Neovim.

Install

With vim-plug:

vim

Plug 'sema-lisp/sema.vim'

With a native package (Vim 8+ / Neovim):

bash

git clone https://github.com/sema-lisp/sema.vim.git \
  ~/.vim/pack/plugins/start/sema.vim

The repo uses the standard ftdetect/, ftplugin/, syntax/ layout, so no runtimepath override is needed.

Features

Automatic filetype detection for .sema
Syntax highlighting — special forms, LLM/agent primitives, threading macros (->, ->>, as->), keyword/character literals, strings with escapes, and ; / #| … |# comments
Lisp-aware editing — lisp mode with a curated lispwords list, 2-space indentation, and iskeyword extended for Sema identifiers
commentstring/comments configured for ;

Emacs

Major mode with Lisp-aware indentation, REPL integration, imenu, and automatic eglot setup.

Install

From MELPA:

elisp

;; M-x package-install RET sema-mode
(use-package sema-mode
  :ensure t
  :mode "\\.sema\\'")

On Emacs 29+ you can install straight from GitHub:

elisp

(use-package sema-mode
  :vc (:url "https://github.com/sema-lisp/emacs-sema" :rev :newest)
  :mode "\\.sema\\'")

Doom Emacs — in packages.el:

elisp

(package! sema-mode
  :recipe (:host github :repo "sema-lisp/emacs-sema"))

Features

Syntax highlighting (special forms, llm/*/agent/*/conversation/*/tool/* primitives, keyword literals, booleans, nil, characters, numbers, strings, comments)
Lisp-aware indentation layered over lisp-mode
REPL integration — send region, last sexp, or whole buffer to an inferior sema REPL
imenu for functions, variables, macros, agents, tools, and record types
Electric pairs for (), [], {}, ""
LSP — registers sema lsp with eglot automatically (M-x eglot)

Key Bindings

Key	Command	Description
`C-c C-z`	`sema-repl`	Start or switch to the Sema REPL
`C-c C-e`	`sema-send-last-sexp`	Send sexp before point to REPL
`C-c C-r`	`sema-send-region`	Send selected region to REPL
`C-c C-b`	`sema-send-buffer`	Send entire buffer to REPL
`C-c C-l`	`sema-run-file`	Run current file with `sema`

Helix

Tree-sitter highlighting via the dedicated tree-sitter-sema grammar, with the language server and debug adapter wired through languages.toml.

Install

Helix has no plugin system, so support is installed by placing the grammar queries in the runtime directory and merging the language config into ~/.config/helix/. Easiest is the install script:

git clone https://github.com/sema-lisp/helix-sema.git
cd helix-sema
./install.sh

The script copies the queries, merges the language config idempotently, and builds the grammar. Verify with hx --health sema — it should report the language server, debug adapter, tree-sitter parser, and all queries as ✓. (Manual steps are in the repo README.)

Features

Tree-sitter highlighting (grammar pinned to a release tag)
Text objects — maf/mif for functions, mac/mic for agent/tool definitions
Smart auto-pairs, 2-space indentation, and ; line comments
Language server (sema lsp) via the [language-server.sema-lsp] block
Debugging (sema dap) via the [language.debugger] block

Sublime Text

Native .sublime-syntax highlighting with build systems, symbol navigation, and optional LSP.

Install

Via Package Control: open the command palette → Package Control: Install Package → search for Sema. Manual install and per-OS Packages paths are in the repo README.

Features

Syntax highlighting for .sema (special forms, builtins, LLM primitives, keywords, strings, numbers, characters, quote operators)
Comment toggling (Cmd+/ / Ctrl+/) — line ; and block #| |#
Symbol navigation (Cmd+R) for define, defun, defmacro, defagent, deftool, …
Build systems for running (sema), formatting (sema fmt), and compiling (sema compile)
Language server (sema lsp) via the LSP package — completions, hover, go-to-definition, references, rename, signature help, and diagnostics

Editor Support ​

VS Code ​

Install ​

Features ​

Zed ​

Install ​

Features ​

IntelliJ IDEA ​

Requirements ​

Install ​

Features ​

Neovim ​

Install ​

Features ​

Vim ​

Install ​

Features ​

Emacs ​

Install ​

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Key Bindings ​

Helix ​

Install ​

Features ​

Sublime Text ​

Install ​

Features ​

Editor Support

VS Code

Install

Features

Zed

Install

Features

IntelliJ IDEA

Requirements

Install

Features

Neovim

Install

Features

Vim

Install

Features

Emacs

Install

Features

Key Bindings

Helix

Install

Features

Sublime Text

Install

Features