Clojars Project Build Status AppVeyor Downloads Dependencies Status

Clojure wrapper for Less4j Java implementation of Less compiler. This repository also contains Boot and Leiningen tasks.

For parallel Sass library check sass4clj


  • Load imports directly from Java classpath (e.g. Webjars)
    • Add dependency [org.webjars.bower/bootstrap "3.3.6"] to use Bootstrap

Boot Clojars Project Downloads

  • Provides the less task (deraen.boot-less/less)
  • For each .main.less file in the fileset creates equivalent .css file.
  • Check boot less --help for task options.

Leiningen Clojars Project Downloads

  • Provides the less4j task
  • For each .main.less file in source-dirs creates equivalent .css file.
  • Check lein help less4j for options.

Import load order

Loading order for @import "{name}"; on file at {path}

  1. Local file at {path}/{name}.less
  2. Classpath resource (io/resource "{name}.less")
  3. Classpath resource (io/resource "{path}/{name}.less")
  4. Webjar asset
    • Resource META-INF/resources/webjars/{package}/{version}/{path} can be referred using {package}/{path}
    • For example @import "bootstrap/less/bootstrap.less"; will import META-INF/resources/webjars/bootstrap/3.3.6/less/bootstrap.less


Log configuration

If you don't have any slf4j implementations you will see a warning:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See for further details.

To disable this add a no operation logger to your project. As this is only required on build phase, you can use :scope "test" so that the dependency is not transitive and is not included in uberjar. Alternatively you can add this dependency to your Leiningen dev profile.

[org.slf4j/slf4j-nop "1.7.13" :scope "test"]


Copyright © 2014-2016 Juho Teperi

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.