Epher for Visual Studio Code, VSCodium, and Cursor

epher is a calculator language: you write ordinary math, with units that convert, and every statement's answer appears inline, right next to the line that produced it.

Edit text files with an extension of type '.epher', such as 'triangle.epher'.

Download the epher calculator, and a large selection of ready-made scripts from epher.org.

Type a formula and the answer is already there. No runnable repl in a side panel, no print statements: the editor is the calculator.

What you get

• Answers inline: each statement's result renders next to its line: x = 40 + 2 shows = 42.
• Units that convert: 6371 km, 55 mile/hr, 30 deg are quantities, not comments. speed in km/hr converts; the answer carries the right unit.
• Live diagnostics: syntax errors point at the exact token, and evaluation errors carry the same message the epher calculator shows.
• Hover signatures: hover any name for its canonical signature; your own functions show their definitions, catalog functions show their docs.

• Completion: the whole catalog (math, astronomy, statistics), your own definitions, keywords, and snippets for the common statement shapes.

• Unit-aware coloring: semantic tokens color unit suffixes by meaning: the m in 2 m is a unit, not a variable.

Quick start

1. In VS Code: Extensions view → search for Epher → Install (or run ext install upyesp.epher). The marketplace page has the listing.
2. In VSCodium: Extensions view → search for Epher → Install. VSCodium searches Open VSX by default, which carries the same extension.
3. In Cursor: Extensions view → search for Epher → Install. Cursor searches Open VSX through its own reviewed marketplace proxy, and the same extension is served there.
4. Open any .epher file and start calculating.

On another fork, or prefer to sideload? Get epher-vscode.vsix from the releases page, then Extensions view → the ⋯ menu → Install from VSIX… (the wasm-wasi runtime it rides on installs itself as a dependency).

The language server ships inside the extension: a WebAssembly build of the same epher-lsp server the other editors use. Nothing is downloaded on first use, and it works offline.

Running a script

One behaviour, however you start it: the Run script CodeLens at the top of the editor (the play icon), Ctrl+Enter / Cmd+Enter, F5, Ctrl+F5, or the command palette. The whole file runs, the answers print in the Debug Console, and the results pane opens beside the editor with the same transcript, clickable back to its lines, plus every graph the run produced as inline SVG.

epher has nothing to pause or step through: statements evaluate in order and the answers are the whole transcript, so the run rides a run-only debug adapter with no breakpoints and F5 simply means "run". A launch.json entry works too (type: "epher", request: "launch", program: path to script); the Add Configuration menu offers the snippet.

Works in the browser too

The same extension runs on vscode.dev and github.dev: press . on any GitHub repository to open it in the browser, with the same inline answers.

Requirements

• VS Code 1.88 or newer (and the forks: Cursor, VSCodium; or a web host). The ms-vscode.wasm-wasi-core runtime installs automatically with the extension.
• No other setup: no compiler, no runtime, no network after install.

Troubleshooting

If the server cannot start, editing still works through the TextMate baseline (highlighting and snippets); only the live features wait. A window reload retries. The Output panel's Epher channel says what happened.

Data and telemetry

None. Everything evaluates on your machine.

License

MIT

npm install
npm run compile          # syncs shared assets, typechecks, bundles both entries
npx @vscode/vsce package --no-dependencies

rustup target add wasm32-wasip1-threads
cargo build -p epher-lsp --target wasm32-wasip1-threads --release
mkdir -p server
cp ../../target/wasm32-wasip1-threads/release/epher-lsp.wasm server/