ludic/tools/editors/jetbrains

Ludic for JetBrains IDEs

Works in IntelliJ IDEA (Community and Ultimate), CLion, GoLand, PyCharm, Rider, WebStorm — anything on the IntelliJ Platform 2024.2 through 2026.2 (since-build 242, until-build 262.*).

until-build 262 is deliberately ahead of the newest released platform — 2025.3 is build 253, and no 262 IDE exists yet. That headroom is the point: an until-build pinned to today's IDE gets the plugin auto-disabled the moment a user upgrades.

Two things are machine-checked rather than assumed, because a plugin that packages cleanly can still fail to load:

• ./gradlew verifyPlugin runs JetBrains' own Plugin Verifier over the built artifact against 2025.3 and reports Compatible, with no deprecated or scheduled-for-removal API usages.
• ./gradlew runIde boots a real IDEA 2025.3 with the plugin installed. The sandbox log line to look for is Loaded custom plugins: LSP4IJ (0.20.1), Ludic (1.5.0) in .intellijPlatform/sandbox/Ludic/IC-2025.3/log/idea.log.

If the plugin does not appear in Settings -> Plugins after installing, the cause is almost always that the IDE's build number is outside since-build..until-build. IntelliJ installs the declared dependency (LSP4IJ) from Marketplace first and only then rejects the incompatible plugin, so the symptom is "LSP4IJ got installed, mine did not". Check Help -> About for the build number and widen pluginUntilBuild in gradle.properties to match.

Building

Gradle must run on JDK 17–21. A newer JDK fails with a bare version number as the error message, which is not obvious the first time you see it:

export JAVA_HOME=$(/usr/libexec/java_home -v 21)     # macOS
cd tools/editors/jetbrains
./gradlew buildPlugin        # -> build/distributions/Ludic-1.5.0.zip
./gradlew runIde             # try it in a sandbox IDE

The first build downloads an IntelliJ IDEA Community distribution (over 1 GB), so expect it to take a while; later builds take seconds. Once the cache is warm,

LUDIC_TEST_JETBRAINS=1 bin/ludic-dev test-tools

includes the plugin build in the toolchain's own test run.

Install the zip with Settings -> Plugins -> ⚙ -> Install Plugin from Disk. LSP4IJ is a required dependency; the IDE offers to install it for you.

What you get

• Editing: highlighting (Settings | Editor | Color Scheme | Ludic), brace and quote pairing, folding, # comments, smart indent on Enter and on typing a closer, Code Style page (2 spaces by default), live templates (prog, handler, on, test, fn, forq, ...), package.ludic directives.
• Language server (ludic-lsp via LSP4IJ): completion, diagnostics (including the compiler's own on save), hover, parameter info, go to definition, find/highlight usages, rename, formatting, inlay hints, semantic colours, Structure view, breadcrumbs, Go to Symbol.
• Run / test: a Ludic run configuration (ludic run, build, test or any other ludic command); green gutter buttons on program and on every test "name" (which runs just that test via ludic test --test NAME); results in the test tree with navigation; file.ludic:line links in every console. Per-test results need a toolchain with ludic test --verbose (0.17+); an older one still gives per-file results.
• Project: File | New | Project | Ludic (runs ludic new), File | New | Ludic File (program, module, test), Tools | Ludic (run, build, test, fmt, get, pack, bundle, clean, doctor).

There is no debugger: ludicc does not emit debug info yet.

Settings

Settings -> Languages & Frameworks -> Ludic — the paths to ludic, ludic-lsp and ludicc. Each blank one is looked up in bin/ under the project root, then on PATH, then in ~/.ludic/bin. Changing a path restarts the language server.

Testing

./gradlew test                     # ~70 headless platform tests, ~25 s
./gradlew verifyPlugin -PlocalIde="/Applications/IntelliJ IDEA.app"   # also verify against an installed IDE
./gradlew runLocalIde -PlocalIde="/Applications/IntelliJ IDEA.app" -PopenProject=/path/to/game