GAP Help

Search and read GAP documentation directly in VS Code.

Supports word-selection lookup, real-time QuickPick search (matching the behavior of GAP's ?help and ??help), with results displayed in a webview panel that supports in-page link navigation and MathJax math rendering.

GAP is a system for computational discrete algebra, with particular emphasis on computational group theory, and is widely used in mathematical research. GAP comes with comprehensive built-in documentation. This extension builds on GAP's native help system, aiming to help GAP users learn and work with GAP more conveniently. For more information, see the GAP official website.

Usage

After installing, open VS Code settings (Ctrl+,), search for gap-help.gapPath, and enter the path to your GAP installation root (the folder containing doc/ and pkg/).

Path examples

GAP installed via the .exe installer: C:\Program Files\GAP-4.16.0\runtime\opt\gap-4.16.0
GAP built from source: /home/user/gap-4.16.0

The extension includes prebuilt index data for GAP 4.13.1 / 4.14.0 / 4.15.0 / 4.16.0. Just set the path and it is ready to use. For other versions, run GAP: Rebuild Help Index to manually build the index (Windows users need GAP in their system PATH).

The path takes effect immediately, no restart needed.

Windows: add GAP to the system PATH

Rebuilding the index needs the gap command. Using GAP 4.16.0 as an example, run the following in PowerShell (replace with your actual installation path):

$userPath = [Environment]::GetEnvironmentVariable('PATH', 'User')
[Environment]::SetEnvironmentVariable('PATH', $userPath + ';C:\Program Files\GAP-4.16.0\runtime\opt\gap-4.16.0;C:\Program Files\GAP-4.16.0\runtime\bin', 'User')

Restart your terminal and run gap --version to verify.

Features

Prebuilt index data for GAP 4.13.1~4.16.0: ready to use once the path is set.
Two search modes, switchable in settings or from the QuickPick search box:
- prefix: equivalent to GAP's ?help
- substring: equivalent to GAP's ??help
For other GAP versions, manually rebuild by pressing Ctrl+Shift+P and typing GAP: Rebuild Help Index.
Search results are displayed in a webview panel with support for in-page link navigation and MathJax math rendering.
Document appearance is globally controllable: system follows the VS Code theme, dark / light force a mode for all manuals, and the [Style] link inside the docs adjusts it.
MathJax has a global switch, synced bidirectionally with the [MathJax on/off] link inside the docs, and toggling keeps your scroll position.

Settings

Setting	Default	Description
`gap-help.gapPath`	(empty)	GAP installation root (the folder containing `doc/` and `pkg/`)
`gap-help.searchMode`	`prefix`	Search mode: `prefix` matches `?help` (from word start), `substring` matches `??help` (anywhere)
`gap-help.helpStyle`	`native`	Page rendering style. Currently only `native` (GAP's original look)
`gap-help.docAppearance`	`system`	Document appearance: `system` follows the VS Code theme, `dark` / `light` force a mode for all manuals
`gap-help.mathJax`	`true`	Render math with MathJax. Synced with the `[MathJax on/off]` link inside the docs

Demonstration

The following demonstrates the main features: word-selection lookup, QuickPick search, book filtering, opening the GAP Reference Manual from the context menu, and in-page link navigation within the webview panel.

Word-Selection Lookup

Select a word in GAP code, right-click and choose Help in GAP.

QuickPick Search

Press Ctrl+Shift+P and type GAP: Help in GAP, or right-click in the editor and choose Help in GAP to open the QuickPick search box. Type your query and select a result to view it.