Squarespace LESS Compiler
A Java implementation of the LESS CSS preprocessor language.
Current Less.js compatibility level: 1.3.3
License: Apache 2.0 (summary)
Copyright (c) 2014 Squarespace, Inc.
Project Goals
- Migrate away from use of Node.js + Less.js for server-side conversion of LESS to CSS.
- Maintain compatibility with Less.js, tracking version 1.3.3 (Squarespace's supported version at the time of development).
- Improve performance, reduce memory usage where possible.
- Design must support additional features needed for server-side compilation.
- Design parsing package to closely track the Less.js parser structure, to simplify verifying correctness.
Features
- Performance improvement of 2-5x over Less.js when used in server context
- Improved error messages with full stack traces
- Execution trace mode
- Modular parser that supports fine-grained unit testing of syntax fragments
- High test coverage.
Differences
- JavaScript evaluation support is missing. It may return if / when we can guarantee speed and safety of JS evaluation in the JVM (Java 8's Nashorn may provide this).
- Final CSS structure is generated by feeding blocks and rules to a simple model that ensures they are emitted at the correct scope in the output document.
- Color keywords can participate in math operations.
- See more complete list of differences
Usage
git clone [email protected]:Squarespace/squarespace-less.git
cd squarespace-less
gradle makeCli
./lessc -h
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