sass advanced syntax

github address: https://github.com/lily1010/sass/tree/master/course03

The sass syntax used is:

sass --watch test.scss:test.css --style expanded

As shown below:

1 Import external files, the default file suffix is ​​sass/scss file by default, usually declared in the header

test.scss content is:

<span style="color: #000000;">@import "lili.scss";  //导入一个文件
@import "lili.scss", "haha.scss"; //导入两个文件 
/*但在以下情况下， 仅作为普通的 CSS @import 规则语句，不会导入任何 Sass 文件。
*(1) 如果文件的扩展名是 .css。
*(2) 如果文件名以 http:// 开始。
*(3) 如果文件名是 url()
*(4)如果@import 中包含任何的媒体查询（media queries)
*/
@import "lili.css";
@import "http://foo.com/bar";
@import url(lili);
@import "lili" screen;

/*在import里面插入动态变量,但是仅适用于url方式*/
$name:family;
@import url("http://fonts.googleapis.com/css?family=#{$name}");

/*导入scss文件,却不需要将它编译为css文件做法:
 *(1)新建一个文件夹,为了将不需要编译的文件和需要编译的文件分开,这点千万注意
 *(2)在已经建好的文件夹里面,将不要编译的*.scss文件命名为_*.scss
 *(3)导入的时候不要用下划线,直接@import("新建文件夹名字/*.scss")
 */</span>

The content of lili.scss is:

<span style="color: #000000;">.test1 {
    color: black;
}</span>

The content of haha.scss is:

<span style="color: #000000;">.test11 {
    color: deeppink;
}</span>

The content compiled into test.css is:

<span style="color: #000000;">@import url(lili.css);
@import "http://foo.com/bar";
@import url(lili);
@import "lili" screen;
@import url("http://fonts.googleapis.com/css?family=family");
.test1 {
  color: black;
}

.test1 {
  color: black;
}

.test11 {
  color: deeppink;
}</span>

2 The extend function not only inherits the style of the class name selector, but also inherits the styles related to it, including inheriting its parent selector

test.scss content is:

<span style="color: #000000;">.test2 {
  border: 1px #f00;
  background-color: #fdd;
}
.test2.test21 {
  background-image: url("/image/hacked.png");
}
.test2 .test22 {
  background-image: url("/image/haha.png");
}
html .test2 {
  width: 100px;
}
.lili {
  @extend .test2;
  border-width: 3px;
} </span>

The content compiled into test.css is:

.test2, .lili {
  border: 1px #f00;
  background-color: #fdd;
}

.test2.test21, .test21.lili {
  background-image: url("/image/hacked.png");
}

.test2 .test22, .lili .test22 {
  background-image: url("/image/haha.png");
}

html .test2, html .lili {
  width: 100px;
}

.lili {
  border-width: 3px;
}

3 extend function, inherits the single element selector style, and inherits the styles related to it, including inheriting its parent selector

test.scss content is:

<span style="color: #000000;">a:hover {
    color: green;
}
a.class1:hover {
    height: 10px;
}
html a:hover {
    width: 10px;
}
.test3 {
    @extend a:hover;
    width: 20px;
}</span>

The content compiled into test.css is:

<span style="color: #000000;">a:hover, .test3 {
  color: green;
}

a.class1:hover, .class1.test3 {
  height: 10px;
}

html a:hover, html .test3 {
  width: 10px;
}

.test3 {
  width: 20px;
}</span>

4 extend medium chain expansion

test.scss content is:

<span style="color: #000000;">.test4 {
    width:20px;
}
.test41 {
    @extend .test4;
    height: 20px;
}
.test42 {
    @extend .test41;
    top:20px;
}</span>

The content compiled into test.css is:

<span style="color: #000000;">.test4, .test41, .test42 {
  width: 20px;
}

.test41, .test42 {
  height: 20px;
}

.test42 {
  top: 20px;
}</span>

5 Placeholder%,% will not be compiled into css

test.scss content is:

<span style="color: #000000;">.test5 a%name {
    width: 100px;
}
.lili {
    height: 200%;
    @extend %name;
}</span>

The content compiled into test.css is:

<span style="color: #000000;">.test5 a.lili {
  width: 100px;
}

.lili {
  height: 200%;
}</span>

6 To prevent errors in inheriting non-existent styles in extend, use !optional to skip empty styles directly

test.scss content is:

<span style="color: #000000;">.test6 {
    @extend noexist!optional;
    height: 100px;
}</span>

The content compiled into test.css is:

<span style="color: #000000;">.test6 {
  height: 100px;
}</span>

7 The @at-root directive causes one or more rules to be output at the root level of the document instead of being nested under its parent selector

test.scss content is:

<span style="color: #000000;">.test7 {
    height: 20px;
    @at-root {
        .children1 {
            color: red;
        }
        .children2 {
            color: black;
        }
    }
}</span>

The content compiled into test.css is:

<span style="color: #000000;">.test7 {
  height: 20px;
}
.children1 {
  color: red;
}

.children2 {
  color: black;
}</span>

8 @at-root(without:class name) moves the selector outside the nested directive

test.scss content is:

<span style="color: #000000;">.gaga {
    @media name {
      .page {
        width: 8px;
        @at-root (without: media) {  //注意此处目前测试是不支持类名的,比如.test8
          color: red;
        }
      }
    }
}</span>

The content compiled into test.css is:

<span style="color: #000000;">@media name {
  .gaga .page {
    width: 8px;
  }
}
.gaga .page {
  color: red;
}</span>

9 If conditional judgment, please note that if...else...

is not supported

test.scss content is:

.test8 {   //<span style="color: #0000ff;">if</span>...<span style="color: #0000ff;">if</span><span style="color: #000000;">..
    @</span><span style="color: #0000ff;">if</span> 1+1 == 2<span style="color: #000000;"> {
        width: 20px;
    }
    @</span><span style="color: #0000ff;">if</span> 5  {
        width: 100px;
    }
}
.test81 {  //<span style="color: #0000ff;">if</span>...<span style="color: #0000ff;">else</span> <span style="color: #0000ff;">if</span><span style="color: #000000;">...
    @</span><span style="color: #0000ff;">if</span> 1+1 != 2<span style="color: #000000;"> {
        width: 20px;
    }
    @</span><span style="color: #0000ff;">else</span> <span style="color: #0000ff;">if</span> 5 > 3<span style="color: #000000;"> {
        width: 100px;
    }
}
.test82 {  </span>//<span style="color: #0000ff;">if</span>...<span style="color: #0000ff;">else</span> <span style="color: #0000ff;">if</span>...<span style="color: #0000ff;">else</span><span style="color: #000000;">...
    @</span><span style="color: #0000ff;">if</span> 1+1 != 2<span style="color: #000000;"> {
        width: 20px;
    }
    @</span><span style="color: #0000ff;">else</span> <span style="color: #0000ff;">if</span> 5  { 
        width: 100px;
    }
    @<span style="color: #0000ff;">else</span><span style="color: #000000;"> {
        width: 10px;
    }
}</span>

The content compiled into test.css is:

<span style="color: #000000;">.test8 {
  width: 20px;
}

.test81 {
  width: 100px;
}

.test82 {
  width: 10px;
}</span>

10 for loop statement

test.scss content is:

//第一种格式 @<span style="color: #0000ff;">for</span> $var <span style="color: #0000ff;">from</span> <start> through <end>,注意范围包括<start>和<end><span style="color: #000000;">的值
@</span><span style="color: #0000ff;">for</span> $i <span style="color: #0000ff;">from</span> 1 through 3<span style="color: #000000;"> {
    .gray</span><span style="color: #008000;">#</span><span style="color: #008000;">{$i*3} {</span>
        color: <span style="color: #008000;">#</span><span style="color: #008000;">333*$i; </span>
<span style="color: #000000;">    }
}

</span>//第二种格式 @<span style="color: #0000ff;">for</span> $var <span style="color: #0000ff;">from</span> <start> to <end>,注意范围从<start>开始运行，但不包括<end><span style="color: #000000;">的值
@</span><span style="color: #0000ff;">for</span> $i <span style="color: #0000ff;">from</span> 1 to 4<span style="color: #000000;"> {
    .gray2</span><span style="color: #008000;">#</span><span style="color: #008000;">{$i*3} {</span>
        color: <span style="color: #008000;">#</span><span style="color: #008000;">333*$i; </span>
<span style="color: #000000;">    }
}</span></end></start></end></start></end></start></end></start>

The content compiled into test.css is:

<span style="color: #000000;">.gray3 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">333333;</span>
<span style="color: #000000;">}

.gray6 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">666666;</span>
<span style="color: #000000;">}

.gray9 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">999999;</span>
<span style="color: #000000;">}

.gray23 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">333333;</span>
<span style="color: #000000;">}

.gray26 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">666666;</span>
<span style="color: #000000;">}

.gray29 {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">999999;</span>
}

11 each loop statement @each $var in

test.scss content is:

$name:<span style="color: #800000;">"</span><span style="color: #800000;">lili</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">yaya</span><span style="color: #800000;">"</span>,<span style="color: #800000;">"</span><span style="color: #800000;">sansa</span><span style="color: #800000;">"</span>;  //<span style="color: #000000;">注意数组list的写法
@each $i </span><span style="color: #0000ff;">in</span><span style="color: #000000;"> $name {
    test9.</span><span style="color: #008000;">#</span><span style="color: #008000;">{$i} {</span>
<span style="color: #000000;">        width: 10px;
    }
}

$name2:(name21:</span><span style="color: #800000;">"</span><span style="color: #800000;">lili</span><span style="color: #800000;">"</span>,name22:<span style="color: #800000;">"</span><span style="color: #800000;">yaya</span><span style="color: #800000;">"</span>,name23:<span style="color: #800000;">"</span><span style="color: #800000;">sansa</span><span style="color: #800000;">"</span>);  //<span style="color: #000000;">注意对象map的写法
@each $i </span><span style="color: #0000ff;">in</span><span style="color: #000000;"> $name2 {
    test9.</span><span style="color: #008000;">#</span><span style="color: #008000;">{$i} {</span>
<span style="color: #000000;">        width: 10px;
    }
}

$name3:(name31:</span>1,name32:2,name33:3);  //<span style="color: #000000;">注意对象map的写法
@each $key,$value </span><span style="color: #0000ff;">in</span><span style="color: #000000;"> $name3 {
    test9.</span><span style="color: #008000;">#</span><span style="color: #008000;">{$key} {</span>
        width: 10px*<span style="color: #000000;">$value;
    }
}</span>

The content compiled into test.css is:

test9.lili {
  width: 10px;
}

test9.yaya {
  width: 10px;
}

test9.sansa {
  width: 10px;
}

test9.name21 lili {
  width: 10px;
}

test9.name22 yaya {
  width: 10px;
}

test9.name23 sansa {
  width: 10px;
}

test9.name31 {
  width: 10px;
}

test9.name32 {
  width: 20px;
}

test9.name33 {
  width: 30px;
}

　

12 while loop statement

test.scss content is:

$i:3;
@while $i > 0 {
    .gray#{$i} {
        color: #333*$i;
    }
    $i:$i - 1; //注意此处不能写成$i:$i-1,因为会被当成字符串
}

The content compiled into test.css is:

.gray3 {
  color: #999999;
}

.gray2 {
  color: #666666;
}

.gray1 {
  color: #333333;
}

　

13 Mix instructions to achieve code block reuse

test.scss content is:

@mixin left01 {  //不带参数
    float: left;
}
.test10 {
    @include left01; 
}

@mixin left02($left) {  //带1个参数
    float: $left;
}
.test101 {
    @include left02(left); 
}

@mixin left03($left,$width) {  //带2个参数,或者说参数为数组
    float: $left;
    .lili {
        width: $width;
    }
}
.test102 {
    @include left03(left,100px); 
}

@mixin left04($name31,$name32,$name33) {  //参数为对象,但是接受传递的参数必须是对象相对应key,同时需要用...传递参数
    .lili {
        width: $name31;
        height: $name32;
        top: $name33;
    }
}
$map:(name31:"1px",name32:"2px",name33:"3px");
.test103 {
    @include left04($map...); 
}

@mixin left05($left:right) {  //带默认参数,不传参的话就用默认参数
    float: $left;
}
.test104 {
    @include left05; 
}

@mixin box-shadow($shadows...) {  //不定参数,用...
      -moz-box-shadow: $shadows;
      -webkit-box-shadow: $shadows;
      box-shadow: $shadows;
}
.shadows {
  @include box-shadow(0px 4px 5px #666, 2px 6px 10px #999);
}

The content compiled into test.css is:

.test10 {
  float: left;
}

.test101 {
  float: left;
}

.test102 {
  float: left;
}
.test102 .lili {
  width: 100px;
}

.test103 .lili {
  width: "1px";
  height: "2px";
  top: "3px";
}

.test104 {
  float: right;
}

.shadows {
  -moz-box-shadow: 0px 4px 5px #666, 2px 6px 10px #999;
  -webkit-box-shadow: 0px 4px 5px #666, 2px 6px 10px #999;
  box-shadow: 0px 4px 5px #666, 2px 6px 10px #999;
}

　

14 Pass the content block @content to the mixin and pass it to the @content position

test.scss content is:

<span style="color: #000000;">@mixin lala {
    html {
        color: </span><span style="color: #008000;">#</span><span style="color: #008000;">888;</span>
<span style="color: #000000;">        @content;
    }
}
@include lala {  </span>//<span style="color: #000000;">此处名字必须和上面保持一致
    .logo {
        font</span>-<span style="color: #000000;">size: 15px;
    }
}</span>

The content compiled into test.css is:

<span style="color: #000000;">html {
  color: </span><span style="color: #008000;">#</span><span style="color: #008000;">888;</span>
<span style="color: #000000;">}
html .logo {
  font</span>-<span style="color: #000000;">size: 15px;
}</span>

15 Variables are mixed in the scope of @mixin, that is, the content block passed to the mixin is operated in the scope in which it is defined, not the scope of the mixin. This means that local variables from mixins cannot be passed to style blocks for use

test.scss content is:

$color: white;
@mixin haha($color:black) {
    background-color: $color;
    @content;
}
.test12 {
    @include haha{
        color: $color;
    }
}

编译成test.css内容是:

<span style="color: #000000;">.test12 {
  background</span>-<span style="color: #000000;">color: black;
  color: white;
}</span>

 

16 函数,用法类似@mixin

test.scss内容是:

<span style="color: #000000;">@function sasa($name) {
    @</span><span style="color: #0000ff;">return</span><span style="color: #000000;"> $name;
}
.test13 {
    font</span>-<span style="color: #000000;">size: sasa(15px);
}</span>

编译成test.css内容是:

<span style="color: #000000;">.test13 {
  font</span>-<span style="color: #000000;">size: 15px;
}</span>