User-defined value conversion function

[aarontam]

We wanted to create a function to smartly convert measurements in existing LESS files to resolution-independent units. Is there a recommended way of doing this so that we only pass the measurement value, and not the entire property set? We had tried some of the techniques mentioned in #637, but there were issues with complex calculations passed to our function i.e. height: 2*@myVar + 10 and wanting to pass 2*@myVar + 10 to our function. Additionally, we had looked into the technique mentioned in less/old-lesscss.org#54, but need support in node as well as the browser. Are there any recommendations on the best way to implement our conversion function? Thanks!

[bassjobsen]

An example can be found at https://stackoverflow.com/questions/23834839/how-to-compute-the-cubehelix-color-scheme-in-less-js/26730511

[aarontam]

Interesting, thanks for the link. Anyway to do so without creating a custom distribution of LESS? :) We are on LESS 1.7 and looking into creating a plugin - would this be the most flexible approach so that we don't get feature-locked by modifying core LESS files?

[lukeapage]

Upgrade to 2.0 then use plugins http://lesscss.org/usage/#plugins-for-plugin-authors

Sorry for the slow response.

I've realised there is no function example, but it is along the same lines, you write a short js file and register new functions in the plugin init.

[aarontam]

Hi @lukeapage thanks for the response, that should work for us. Is there any documentation on adding rules via plugin?

Edit: I'll open a new issue for this as it is somewhat unrelated, thanks.

[bassjobsen]

Hi @aarontam,

Please see : http://stackoverflow.com/questions/27809514/how-to-exend-the-less-compiler-with-a-custom-function-leveraging

The list of plugin is growing, see http://lesscss.org/usage/#plugins-list-of-less-plugins. You can use these plugins as an example.
To add rules you can use a visitor plugin (example https://github.com/less/less-plugin-inline-urls) or a postprocess plugin (example: https://github.com/less/less-plugin-autoprefix ).

If you got any not working code already, you could post a question on stack overflow too. Or send me an e-mail.

Notice that you also can use plugins to add custom function to Less easy. Examples can be found at https://github.com/less/less-plugin-advanced-color-functions/ (server side ) and https://github.com/bassjobsen/less-plugin-cubehelix (both server and client side)