vim-less-autocompile

Tiny vim plugin that takes care of automatically compiling Less files into a corresponding CSS file on save.

This plugin came about for personal use and is very simple, so it might not handle some edge cases (like unreadable files, etc.). If you find anything lacking, please feel free to open an issue or contribute yourself!

Prerequisites

In order to utilize this plugin, Less needs to be installed. This is done globally via NodeJS:

npm install -g less

It is also recommended to have a Less file type (syntax highlighting) plugin installed. vim-less is a good choice.

Installation

Install using your favorite Vim plugin manager. For example, using vim-plug:

Plug 'Maluscat/vim-less-autocompile'

Usage

There is no global configuration (yet?). Everything is configured on a per-file basis:

To use, simply put a comment on the first line of your Less file that specifies the configuration you want to use (see below). It is a comma separated list of arguments that are passed to the lessc command. An argument itself is denoted as a colon separated key-value pair.

Mandatory arguments

Every file that should be compiled must have one of two mandatory arguments: out or main.

The out argument specifies the destination path for the CSS file that will get compiled on save.

• // out: ./path/to/output.css

You can also redirect the compilation to another file using the main argument instead of out (recursively, if needed). This is useful if the specified files are not intended for direct compilation because they are dependencies of the main file, which should be compiled instead. Multiple files are separated by a pipe without spaces:

• // main: ./path/to/main.less
• // main: ./main1.less|../main2.less|main3.less

Basic example

Assuming both files are in the same folder:

colors.less:

// main: styles.less
@color: red;

styles.less:

// out: styles.css
@include 'colors.less';
body {
  color: @color;
}

Now, when saving of any of the two files, it compiles to:

styles.css

body {
  color: red;
}

Any compilation errors will be accumulated and passed on to Vim.

Other arguments

Besides the mandatory arguments above, any other arguments of the lessc command line tool may be applied in the same manner. For readability (and laziness) purposes, only double-dash arguments may be specified, meaning lint (from lessc --lint) is fine, but l (from lessc -l) will be nonsensical.

The following will compile to a ./main.css with the arguments --lint --source-map=main-map.map:

// out: main.css, lint, source-map: main-map.map
...

When specifying additional arguments in a file that has a main instead of an out, they are merged with the arguments of the main file (recursively, if needed).

Contribution

Any reported issues, feedback, ideas and other contributions are greatly appreciated!