https://github.com/clj-commons/virgil

Recompile Java code without restarting the REPL
https://github.com/clj-commons/virgil

Last synced: about 2 months ago
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Recompile Java code without restarting the REPL

• Host: GitHub
• URL: https://github.com/clj-commons/virgil
• Owner: clj-commons
• Created: 2015-11-19T05:27:19.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2024-07-26T12:48:46.000Z (about 2 months ago)
• Last Synced: 2024-07-26T14:20:29.710Z (about 2 months ago)
• Language: Clojure
• Homepage:
• Size: 531 KB
• Stars: 300
• Watchers: 15
• Forks: 21
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Codeowners: .github/CODEOWNERS

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README

        


Do you tarnish your Clojure with the occasional hint of Java? Have you become

indescribably tired of reloading your REPL every time you change anything with a

`.java` suffix? Look no further.

Virgil is a library for live-recompiling Java classes from the REPL. This can be

done either manually or by starting a process that watches your source

directories for changes in Java files and triggering recompilation when that

happens.

### Usage

Add `virgil/virgil` dependency to your `project.clj` or `deps.edn`. If you plan

to use Virgil just as a devtime dependency, then you probably want to add it to

a profile/alias which you enable only during development.

[![](https://clojars.org/virgil/virgil/latest-version.svg)](https://clojars.org/virgil/virgil)

```clj

(require 'virgil)

;; To recompile once, manually:

(virgil/compile-java ["src"])

;; To recompile automatically when files change:

(virgil/watch-and-recompile ["src"])

```

The main argument to these functions is a list of directories where Java source

files are located. Both functions can accept a list of string `:options` that is

passed to Java compiler, e.g. `:options ["-Xlint:all"]` to print compilation

warnings, and a `:verbose` flag to print all classnames that got compiled.

`watch-and-recompile` accepts an optional `:post-hook` function. You can use it

to, e.g., trigger `tools.namespace` refresh after the classes get recompiled.

Check [example](example) directory for a sample project.

Happy tarnishing.

### Can I use Virgil in production?

Virgil can compile Java classes at runtime in a production environment the same

way as it does during the development, so the answer is yes. However, when you

do a release build, it is advised to build real Java classes explicitly during

your build step using *javac* task of your build tool. There are multiple

arguments for it:

  * You get extra reliability and assurance that the compiled Java classes will

    be correctly discoverable by other code.

  * You get one fewer runtime dependency.

  * You won't have to rely on JDK-specific tools like `javax.tools` package that

    might not be available in your production environment (e.g., if it runs on

    JRE).

### Migration from 0.1.9

From version 0.3.0, Virgil no longer provides `lein-virgil` plugin for

Leiningen. Instead, you should add `virgil` it as a regular dependency to your

project and call its functions from the REPL.

### Supported versions

Virgil makes sure to support Clojure 1.10+ and JDK 8, 11, 17, 21, 22 (see [CI

job](https://app.circleci.com/pipelines/github/clj-commons/virgil)). Supporting

future versions of Java so far required only bumping ASM library dependency, so

that shouldn't take long. Please, create an issue if you run into any

compatibility problems.

### License

Copyright © 2016-2019 Zachary Tellman, 2022-2024 Oleksandr Yakushev

Distributed under the MIT License