TypeSwap

Instantly replace typed text using your own substitution rules — TeXShop-style "key bindings" for VS Code / Cursor.

🇯🇵 日本語版 README はこちら (Japanese README)

TypeSwap watches what you type and replaces it the moment it appears, based on a list of rules you define. It is inspired by the key bindings feature of TeXShop, the macOS TeX editor — but works for any language, not just TeX.

Typical uses:

• Type ¥ on a Japanese keyboard and get \ in your LaTeX source
• Type $ with text selected and get the selection wrapped as $…$, cursor placed at the end
• Type " and get proper TeX quotation marks ``…''
• Convert full-width spaces to half-width spaces as you type

Quick start

Install the extension — it works immediately. These rules are preconfigured:

To customize the rules, run TypeSwap: Edit Replacement Rules (GUI) from the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) — no need to touch settings.json. You can also edit typeswap.rules in settings.json directly if you prefer.

The #SEL# marker — use the selection

If to contains #SEL#, the text selected just before typing is inserted at that position. With no selection, #SEL# simply disappears.

#SEL# may appear multiple times; every occurrence receives the same selected text.

The #INS# marker — place the cursor

If to contains #INS#, the cursor moves to that position after the replacement. The marker itself is removed from the output. Multiple #INS# markers create multiple cursors (multi-cursor mode).

Combining #SEL# and #INS# gives you snippet-like behavior from plain typing.

Rule properties

Each entry of typeswap.rules supports:

Language filtering

• typeswap.enabledLanguages (global): language IDs where TypeSwap is active at all. Empty array (default) = all languages. This one is editable directly in the Settings UI.
• Per-rule override: each rule's enabledLanguages / disabledLanguages refine or override the global setting.

Evaluation order (first match wins):

1. Language is in the rule's disabledLanguages → inactive
2. The rule's enabledLanguages is non-empty → active iff the language is listed (overrides the global setting)
3. Otherwise → follow the global typeswap.enabledLanguages

Paste behavior

By default, pasted text is not modified. Set replaceOnPaste: true on a rule to apply it to pasted content too.

How paste is detected: the VS Code API cannot distinguish keystrokes from paste, so any change of two or more characters is treated as paste-like. IME commits (e.g. Japanese input) may therefore also count as "paste".

Notes

• from is a literal string — regular expressions are not supported.
• Rules whose from is longer than one character never trigger on keystrokes, only on paste (with replaceOnPaste: true).
• When several rules match the same change, they are applied in list order.
• A single Undo (Cmd+Z / Ctrl+Z) restores the text exactly as typed.
• In settings.json, a backslash in to must be written as "\\" (JSON escaping).
• The yen sign (¥, U+00A5) and the backslash (\, U+005C) are distinct characters; the ¥ key on Japanese keyboards produces U+00A5, so you can write ¥ literally in from.

License

MIT