Preprocessor presentation

CSS Preprocesser Madness LESS/SCSS/Compass/Bootstrap

About Us Mario Noble Charles Mata

Why Madness? Because you may become crazy for it. Or over it. Or maybe just watching this "Powerpoint" will drive you insane.

Preprocessors AKA - The "People's Patch" Our alternative to the cross browser wars. At least for the time being...

Learn CSS and good practices first Preprocessors are not a replacement for good coding, planning and design.

What is preprocessing? Preprocessing is essentially creating the equivalent of a Photoshop file or a suped up mailing template for your css. It gives you added umph to your work. Sometimes making it easier. Occasionally it might be overkill.

Why do it? Do you like to type the same thing over and over? Do you enjoy trying to hunt down a tiny bit of code somewhere in thousands of lines of code and then using find and replace hoping it'll work? No? Use preprocessing.

Most of all - DRY practices Don't Repeat Yourself

Other reasons ● CSS 3 browser prefixes ● Responsive design ● Other people are using it, so you want to have a clue. ● Efficiency ● Better organization ● Faster sites and better SEO

Disadvantages ● Learning curve ● Team Maintenance ● Yet another layer ● Code bloat ● Selectoritis

Methods and Approaches ● SASS/SCSS ● LESS ● Stylus ● cleverCSS ● cssCrush ● prefixer (http://prefixr.com/) ● force browser to interpret PHP as CSS

We're going over the two most popular preprocessors tonight LESS and SASS/SCSS We'll be glossing over some stuff in the interest of time and clarity

Let's go over what they share Each of them now share most of each others capabilities with some minor differences in syntax. The following examples are from Chris Eppstein's gits on: https://gist.github. com/674726 Thanks Chris!

Variables (placeholders) Sass | Less -----------------+----------------- $color: red; | @color: red; div { | div { color: $color; | color: @color; } | } Becomes div { color: #ff0000; }

Nesting (outlining) Sass | Less -------------------+----------------- p { | p { a { | a { color: red; | color: red; &:hover { | &:hover { color: blue; | color: blue; } } } } } Becomes p a {color: red;} p a:hover {color: blue;}

Mixins (mini-templates) Sass | Less ----------------------------------+---------------------------------- @mixin bordered { | .bordered { border-top: dotted 1px black; | border-top: dotted 1px black; border-bottom: solid 2px black; | border-bottom: solid 2px black; } | } | #menu a { | #menu a { @include bordered; | .bordered; } | } Becomes .bordered { border-top: dotted 1px black; border-bottom: solid 2px black; } #menu a { border-top: dotted 1px black; border-bottom: solid 2px black; }

Mixins with arguments (adverbs/adjectives) Sass | Less ----------------------------------+---------------------------------- @mixin bordered($width: 2px) { | .bordered(@width: 2px) { border: $width solid black; | border: @width solid black; } | } | #menu a { | #menu a { @include bordered(4px); | .bordered(4px); } | } Becomes #menu a { border: 4px solid #000000; }

Numbers Sass: Less: 1cm * 1em => 1 cm * em 1cm * 1em => Error 2in * 3in => 6 in * in 2in * 3in => 6in (1cm / 1em) * 4em => 4cm (1cm / 1em) * 4em 2in + 3cm + 2pc => 3.514in => Error 3in / 2in => 1.5 2in + 3cm + 2pc => Error 3in / 2in => 1.5in

Imports (Get that there file!) @import "somefile.less"; @import "somefile"; @import "somefile.scss"; @import "somefile"; @import "somedirectory/somefile.scss";

Interpolation (stick it in there) SCSS style LESS style /* style.scss */ @base-url: "http://assets.fnord.com"; $side: top; background-image: url("@{base-url} /images/bg.png"); $radius: 10px; Becomes: .rounded- { border-#{$side}-radius: $radius; background-image: url("http://assets.fnord. com/images/bg.png");.someclass { -moz-border-radius-#{$side}: $radius; color: #333; -webkit-border-#{$side}-radius: $radius; } }

Escaping (take it literally) LESS .class { filter: ~"ms:alwaysHasItsOwnSyntax.For. Stuff()"; } SASS .class { filter: #{"'ms:alwaysHasItsOwnSyntax.For. Stuff()'"}; } Becomes: .class {filter: ms:alwaysHasItsOwnSyntax.For.Stuff();}

Comments Both LESS and SCSS use the same comment structure. // is a note in the authoring file /* some note */ is published to the compiled file.

@media query tweaking LESS (for SASS/SCSS replace @ with $ for Becomes: variables) .profile-pic { @break-small: 320px; float: left; @break-large: 1200px; width: 250px; } @media screen and (max-width: .profile-pic { 320px) { float: left; .profile-pic { width: 250px; width: 100px; float: none; @media screen and (max-width: @break-small) { } width: 100px; } float: none; @media screen and (min-width: 1200px) { } .profile-pic { @media screen and (min-width: @break-large) { float: right; float: right; } } } }

Differences As with anything, there are advantages and disadvantages of going with various options. LESS and SASS are no different. Or rather they are in some ways...

Extra features of SASS/SCSS ● Can properly "extend" other classes. ● True if, for, while and each control directives (Logic) ● Global scoping of variables ● Compass (sprites) ● Origin line reporting ● Good Rails integration ● Various output styles ● Real functions that return values

Extra features of LESS ● Namespacing ● Guards and Pattern Matching ● Easy compile "on the fly" with a single JavaScript file. ● Variables as constants ● Twitter Bootstrap ● Usual scope practices ● JavaScript evaluation

To compile locally or on the server? Considerations: Performance Coordination Caching Server install

Let's demo some Bootstrap n' Stuff! Go Charles go!

Hands on part! Let's do LESS first Get the example material or use your own http://files.meetup.com/1962521/basicHtmlCss.zip Get the basic js http://lesscss.org - bonus points - download twitter bootstrap Get a complier Mac OSX http://incident57.com/less/ Windows http://winless.org/ Linux/Mac/PC http://wearekiss.com/simpless Get an editor or download the code hinters http://www.sublimetext.com/

Already have the LESS stuff? To install SASS/SCSS Go here: http://sass-lang.com/tutorial.html Download the Windows Installer if you're on Windows. http://rubyinstaller.org/ After that, go to http://compass-style.org/install/ Follow instructions to install both SASS and Compass Download either Scout http://mhs.github.com/scout-app/ Compass app is good too. Just paid. Configure your editor I recommend SublimeText along with the Package Installer to install SCSS/LESS code hinting.

"Converting" your existing CSS Really just nests it. LEAST http://toki-woki.net/p/least/ SASS # Convert Sass to SCSS $ sass-convert style.css style.scss

LESS useful tools if using the js to compile. After you put this into your files: <link rel="stylesheet/less" type="text/css" href=" styles.less"> <script src="less.js" type="text/javascript" ></script> Put this after your file name in the url: #!watch Chrome users: --allow-file-access-from-files in shortcut or use a local server mac : terminal ; open /Applications/Google Chrome.app --args --allow-file-access-from-files

Compiling You can use tools or the command line. SCSS users may need to delve into their config.rb file or just use the tools. LESS users might just want to use the tools to setup publish paths.

Let's have fun with variables @myvariable or $myvariable

Mixins @mixin mymixin { } @include mymixin { } .somemixin { } .anotherclass { .somemixin }

Mixins with parameters @mixin mymixin($hello); @include mymixin(10px); .somemixin(@hello) .somemixin (10px);

Numbers width: $navbar-width/$items - 10px; color: @base-color * 3;

Interpolation border-#{$side}-radius: $radius; border-@{side}-radius: $radius;

Gotchas LESS Keep your import structure flat. SCSS Watch out for imports with .less or not.

Congratz!!!! You has mad skillz nowz!

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