29 Jan
2014
29 Jan
'14
10:42 a.m.
One more thing:
= Cient-Side compilation =
LESS is written in javascript. It is possible to "compile" a .less file to
.css on the server-side, but it is also possible to do it on the
client-side (see: http://www.lesscss.org/#usage ).
In my opinion, it should be always done server-side, but except in one case:
in the color theme editor.
In this case, it is possible to use the JS API of LESS in the browser:
less.modifyVars({
'@buttonFace': '#5B83AD',
'@buttonText': '#D9EEF2'
});
In this example, it changes the color or every buttons on the fly.
= Integration with java =
Some links:
* Official LESS CSS Compiler for Java
** https://github.com/marceloverdijk/lesscss-java
** The compiler uses Rhino, Envjs (simulated browser environment written in
JavaScript), and the official LESS JavaScript compiler.
Example of use:
// Instantiate the LESS compiler
LessCompiler lessCompiler = new LessCompiler();
// Compile LESS input string to CSS output string
String css = lessCompiler.compile("@color: #4D926F; #header { color:
@color; }");
// Or compile LESS input file to CSS output file
lessCompiler.compile(new File("main.less"), new File("main.css"));
* LessCSS4j
** https://github.com/localmatters/lesscss4j
** the author claims it has better performances that the official compiler.
Example of use:
StyleSheetResource resource = new FileStyleSheetResource(filename);
LessCssCompiler compiler = new DefaultLessCssCompilerFactory().create();
compiler.compile(resource, System.out, null);
* Sass-Java:
** https://github.com/darrinholst/sass-java
** "Compiles sass to css on-the-fly with compass
<http://compass-style.org/>via a j2ee servlet filter".
** Not sure if we can use it.
* Others java compilers for sass look dead.
Louis-Marie
2014-01-28 Guillaume "Louis-Marie" Delhumeau <gdelhumeau(a)xwiki.com>
Just my 2 cents:
= About variables =
- in LESS, variables are prefixed by @:
@defaultColor: #004400;
- in SASS, variables are prefixed $, just like velocity:
$defaultColor: #004400;
So, if we use velocity and SASS, what $defaultColor is? A velocity
variable? A sass variable?
We can escape the $ to make the distinction between sass and velocity
variables, but it is not very friendly.
= About mixins =
Mixins are kind of macros, that we have in velocity. I prefer the
implementation of SASS than LESS. The logical operations seem better in
SASS too.
See: http://css-tricks.com/sass-vs-less/
Louis-Marie
2014-01-28 Ecaterina Moraru (Valica) <valicac(a)gmail.com>
Hi,
As part of the 6.0 Roadmap we have as entry the creation/integration of a
new Skin inside XWiki.
Currently there are 2 proposals for the new skin:
Flamingo http://design.xwiki.org/xwiki/bin/view/Improvements/Skin4x
Junco http://design.xwiki.org/xwiki/bin/view/Proposal/JuncoSkin
Both proposals are done using Twitter's Bootstrap framework (
http://getbootstrap.com).
Bootstrap officially is written using Less ( http://www.lesscss.org/ )
and
is the default pre-processor they support. There is also a Sass (
http://sass-lang.com/ ) version for Bootstrap (
https://github.com/twbs/bootstrap-sass ) so the idea is that the
preprocessor variant is not limiting us in integrating Bootstrap.
The question we discuss in this thread is what preprocessor we should
integrate in platform when we integrate Bootstrap (that in the case we
integrate either of these tools).
Currently Junco's extension is done with Bootstrap + Less. My decision to
use this combination was done after a light research and mostly based on a
personal preference of the Less language.
We are having this preprocessors discussion so late (they appeared in
2007-2009) because we didn't really need a preprocessor until now. The
base
functionality they add we solved by using Velocity (we have CSS3 prefix
macros defined in macro.vm that are similar to the compatibility mixins
provided by Bootstrap, we have also a ColorThemes variables solution for
reusing color values and because we can have Velocity code inside our
stylesheets we cover most of the functions&operations need).
The only downside for us using Velocity to do these kind of things is that
the functionality we cover is very basic and was done only if we had a
certain need. This is not necessarily a bad thing but it's kind of a
limitation for external developers that might want to make more complex
things. Less and Sass community members are very active and they make sure
their functionality is tested and covers most of the cases. Also there are
some features (like extends, etc.) that would be hard for us to duplicate
in Velocity.
Just as a note, adding Less doesn't mean we are replacing Velocity. We are
just replacing the CSS things done in Velocity with Less functionality.
Replacing Velocity with another templating engine should be the topic for
another thread (in case we are considering this).
If we integrate Less, what is currently done with CSS+Velocity will be
done
using Less(CSS)+Velocity(less code).
If we integrate Sass (because Sass also has control directives) we
transform CSS+Velocity in Sass(CSS)+Velocity(even less code) but the API
calls will still need to be added with Velocity (so still we will not have
just Sass).
One of the problems with the preprocessors is that they depend on
Javascript or Ruby (there are some versions also on Java in case of Sass,
but not officially maintained). So first we need to find a solution to
compile Less/Scss files into CSS, inside our platform.
If you make a Google search you'll see that there are much more
'recommendations' to pick Sass over Less. One remark regarding this is
that
we need to understand that right now Sass is used on a different
technologies stack (mostly for Ruby applications). Sass is very attractive
because of its power. But what we need to ask ourselves is if we need the
full power of Sass (because some of it is already covered by Velocity).
Personally I prefer Less, but that's because of the separation of concerns
(structure, presentation, behavior). I prefer the limitations Less has
(regarding control structure) in order to not be tempted to write logic
with a language that is not supposed to do that (even though it can).
Preprocessors should be used exclusively to write CSS and especially to
write it more rapid (nesting, mixins).
Also Less syntax is more close to default CSS syntax, which IMO is a big
plus.
But because of its power, Sass could be in the future the new 'JQuery',
since right now it has a bigger community. One of the advantages of
picking
a technology later is that at least you see some clear candidates (and we
don't need to consider other preprocessors like Stylus, etc.).
Let me know what you think.
Thanks,
Caty
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