LESS 中的动态类名

Question

我有以下 LESS 代码在工作

            @iterations: 940;
            @iterations: 940;
            @col:2.0833333333333333333333333333333%;
            // helper class, will never show up in resulting css
            // will be called as long the index is above 0
            .loopingClass (@index) when (@index > -20) {
                // create the actual css selector, example will result in
                // .myclass_30, .myclass_28, .... , .myclass_1
                (~".gs@{index}") {
                    // your resulting css
                    width: (@index/20+1)*@col;
                }
                // next iteration
                .loopingClass(@index - 60);
            }
            // end the loop when index is 0
            .loopingClass (-20) {}
            // "call" the loopingClass the first time with highest value
            .loopingClass (@iterations);

它输出我们的网格系统：

            .gs940 {
              width: 100%;
            }
            .gs880 {
              width: 93.75%;
            }
            .gs820 {
              width: 87.5%;
            }
            .gs760 {
              width: 81.25%;
            }
            .gs700 {
              width: 75%;
            }

等等等等等等

现在我想做的是对类名进行一些数学运算以生成以下类

            .gs220-700
            .gs280-640
            .gs340-580
            .gs400-520
            .gs460-460
            .gs520-400
            .gs580-340
            .gs640-280
            .gs700-220

等等等等等等

基本上这是 .(@index) - (920px 减去 @index)

但我不知道这是否可能。

Answer 1

整个问题对我很有帮助。我只是想发布我的问题的解决方案，因为自LESS v 1.4 以来解决方法已经改变。 LESS Changelog

而不是使用~ 符号，您只需写出您想要的名称部分以及普通的@ 和变量名称，并用{} 包围它。所以：#class@{variable}。

例如，我使用同一种循环的解决方案变成了这样：

/*Total number of passport inserts*/
@numInserts: 5;
/*Total width of the passport foldouts*/
@passportWidth: 300px;
/*Change in passport insert width per iteration*/
@passportWidthDiff: (@passportWidth / @numInserts);
/*"Array" of colors to select from to apply to the id*/
@passportColors: 
blue orange green red yellow 
purple white teal violet indigo;

/*The faux loop the doesn't end up in the final css
@index is the counter
@numInserts is the total number of loops*/
.loopingClass (@index) when (@index <= @numInserts){
   /*This is the created ID with the index appended to it
   You can also do this with classes such as if 
   we had had ".insert@{index}"*/
   #insert@{index}{
      /*Here are our properties that get adjusted with the index*/
      width: (@passportWidth - (@passportWidthDiff * (@numInserts - @index)));
      height: 50px;
      background-color: extract(@passportColors, @index);
      z-index: (@numInserts - @index);
   }
   /*Here we increment our loop*/
   .loopingClass(@index + 1);
}
/*This calls the loop and starts it, I started from 1
since I didn't want to lead a className starting from 0,
But there is no real reason not to.  Just remember to
Change your conditional from "<=" to "<"*/
.loopingClass(1);

并产生以下内容：

#insert1 {
  width: 60px;
  height: 50px;
  background-color: #0000ff;
  z-index: 4;
}
#insert2 {
  width: 120px;
  height: 50px;
  background-color: #ffa500;
  z-index: 3;
}
#insert3 {
  width: 180px;
  height: 50px;
  background-color: #008000;
  z-index: 2;
}
...

Answer 2

我不认为你离得很远。我所做的是在 mixin 中创建第二个变量，称为@index2。所有这些都是找到您正在寻找的 '920px 减去 @index' 值：

@index2 = (920-@index);

然后将其附加到类名：

(~".gs@{index}-@{index2}") {

这是完整的循环：

.loopingClass (@index) when (@index > 160) {
    @index2 = (920-@index);
    // create the actual css selector, example will result in
    // .myclass_30, .myclass_28, .... , .myclass_1
    (~".gs@{index}-@{index2}") {
    // your resulting css
        width: (@index/20+1)*@col;
    }
    // next iteration
    .loopingClass(@index - 60);
}
// "call" the loopingClass the first time with highest value
.loopingClass (@iterations);

为了获得您正在寻找的集合（gs220-700 到 gs700-220），只需将 @iterations 更改为等于 700。

值得注意的是，目前，这将按照您在问题中指定它们的相反顺序创建类。