LESS CSS Compiler Plugin for the IntelliJ Platform

LESS CSS Compiler monitors LESS files and automatically compiles them to CSS whenever they change.

Compiler Version

This plugin uses version 1.6.0 of the official less.js compiler from lesscss.org.

IDE Compatibility

This plugin is ONLY compatible with IntelliJ IDEA 11+, PhpStorm 5+, and WebStorm 5+. It should also be compatible with RubyMine 4.5+, but has not been tested.

Features

1. Recursive Directory Monitoring

   LESS CSS Compiler watches directories (and subdirectories) for changes to LESS files and automatically compiles them to CSS when they are saved in the editor (or when IntelliJ detects that they were modified outside the IDE).

   You can monitor as many LESS directories as you like. You can also specify as many output directories as you like so that compiled CSS files will be copied to multiple locations (e.g., a local src directory under version control and a mounted target directory on a remote server).

   The directory structure of the output CSS directories will be identical to the structure of the source LESS directory.

2. @import Dependency Resolution

   Files that @import a modified LESS file will be re-compiled automatically.

   For example, if home.less, about.less, and contact.less all @import "common.less", modifying common.less will cause all three dependents to be re-compiled as well.

3. Include / Exclude File Patterns

   Prevent specific LESS files from being compiled by specifying include / exclude patterns (glob) that match against filename, folder name, or any part of the complete path to the LESS file.

4. Move, Copy, and Delete Detection

   When a LESS file is moved, copied, or deleted, LESS CSS Compiler will offer to do the same to the corresponding CSS file(s).

5. Virtual Filesystem Notifications

   Unlike other solutions, this plugin is smart enough to notify IntelliJ when CSS files are changed, moved, copied, or deleted. In most cases, updated CSS files will be immediately reflected in the editor and Project tree view.

6. Selective Compilation

   If the plugin somehow fails to catch changes to a LESS file, simply right-click anywhere in the editor or Project tree and select "Compile to CSS". You can also compile an entire directory by right-clicking on it in the Project tree.

7. Error Notifications

   Any errors encountered during the compilation process will produce an error notification balloon in the IDE containing a link to the file and the line number that caused the error.

Usage

Installation

1. Go to File > Settings (Windows / Linux) or IntelliJ IDEA > Preferences (Mac)
2. Install the plugin from the IntelliJ plugin repository
3. Restart the IDE

Configuration

1. Go to File > Settings (Windows / Linux) or IntelliJ IDEA > Preferences (Mac)
2. Under Project Settings, select LESS Compiler
3. Click the + button to add a new LESS profile
4. Choose a LESS source directory
5. Add one or more CSS output directories and click OK
6. Make changes to a LESS file and save it
7. Rejoice!

Directory Structure

LESS CSS Compiler allows you to maintain arbitrarily complex directory structures with ease. For example, suppose we have a project with the following directory structure (LESS CSS Maven Plugin's default layout):

projectRoot/
  +  src/main/
  |  +  less/
  |  |  +  common/
  |  |  |  -  common.less
  |  |  |  -  layout.less
  |  |  |  -  reset.less
  |  |  +  home/
  |  |  |  -  home.less
  |  |  +  checkout/
  |  |  |  -  checkout.less
  |  |  |  -  billing.less
  |  |  |  -  payment.less
  |  +  webapp/
  |  |  +  media/
  |  |  |  +  css/
  |  |  |  |  +  common/
  |  |  |  |  +  home/
  |  |  |  |  +  checkout/
  +  target/
  |  +  media/
  |  |  +  css/
  |  |  |  +  v2/
  |  |  |  |  +  common/
  |  |  |  |  +  home/
  |  |  |  |  +  checkout/

Such a structure would be impossible to maintain using other tools. With LESS CSS Compiler, it's a breeze.

Known Issues

• Slow First Compile

  The first time you update a .less file it will take a few seconds to compile. This is because LESS CSS Compiler uses the Rhino JavaScript engine to run less.js, and Rhino takes a while to initialize. But don't worry - after the initial compilation, all future compiles should complete in < 1 sec.

Alternatives

Notable alternatives to this plugin:

• SimpLESS (Win / Mac) - free
• WinLess (Win) - free

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Developers

Prerequisites

1. Git
2. IntelliJ IDEA 11+ (Community or Ultimate)
3. JDK 6
4. Maven 2 or 3

Running / Debugging the Plugin

1. Clone the repository:

   git clone git://github.com/acdvorak/intellij-lessc-plugin.git
   

2. Ensure required plugins are enabled in IntelliJ:

   • Plugin DevKit
   • UI Designer
   • Maven Integration
   • Properties
   • I18n for Java

3. Import project into IntelliJ:

   1. File > Import Project...

   2. Select the root directory of the Git repository you cloned

   3. Accept the default project name and location

   4. Check all source file directories

   5. UNCHECK the lessc-plugin library

   6. Check all modules

   7. If prompted "The module file 'lessc-plugin.iml' already exist. Would you like to overwrite it?", click Reuse

   8. Select the IntelliJ SDK (IDEA IU-xxx.yyy or IDEA IC-xxx.yyy)

      If you don't see the IntelliJ SDK:

      1. Click the + button and select IntelliJ Platform Plugin SDK
      2. Select the appropriate IntelliJ SDK directory (IntelliJ should automatically select it for you)

   9. Click "Finish"

4. IMPORTANT: Mark module directories appropriately:

   Go to File > Project Structure and select Modules under Project Settings.

   You can also right-click on each directory in the Project tree and select Mark Directory As.

   Directory	Type
   lessc-plugin/src	Sources Root
   lessc-plugin/resources	Resources Root
   asual-lesscss-engine/src/main/java	Sources Root
   asual-lesscss-engine/src/main/resources	Resources Root
   asual-lesscss-engine/src/test/java	Test Sources Root
   asual-lesscss-engine/src/test/resources	Test Resources Root

5. Add a Run/Debug configuration for lessc-plugin, type = Plugin

6. Test the plugin by going to Run > Debug lessc-plugin

TODO

• When a .less file is a descendant of multiple profiles, but is only matched by the include/exclude patterns of a single profile, and the .less file has a syntax error in it, the error message notification is prematurely expired when a later profile's compile job completes "successfully" without changing any .css files (because the .less file doesn't match that profile's patterns).
• "Copy" profile button copies the saved state of the selected profile (it should copy the current state).

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Credits

1. LESS Engine: Asual DZZD (GitHub project)
2. JavaScript Engine: Mozilla Rhino (GitHub project)
3. LESS Compiler: Alexis Sellier (GitHub project)
4. IntelliJ Plugin: Andy Dvorak (Github project)

Copyright and License

Copyright 2012-2013 Andrew C. Dvorak.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.