Question

这是我的问题：我正在研究一系列正则表达式来剖析font属性的简写css代码。以下是我到目前为止的情况：

var style = decl.val.match(/\s*(?:\s*(normal|italic|oblique)){1}/i); style = style ? style[1] : "";
var variant = decl.val.match(/\s*(?:\s*(normal|small-caps))/i); variant = variant ? variant[1] : "";
var weight = decl.val.match(/\s*((?:\s*(?:normal|bold|bolder|lighter|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px))){1})/i); weight = weight ? weight[1] : "";
var size = decl.val.match(/\/\s*((?:\s*(?:xx-small|x-small|small|medium|large|x-large|xx-large|larger|smaller|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px))){1,2})/i); size = size ? size[1] : "";
var height = decl.val.match(/\s*(?:\s*(normal|inherit|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px))){1}/i); height = height ? height[1] : "";
var family = decl.val.match(/\s*(?:\s*([a-zA-Z\-\,\'\"\s]+))(?:,|;)/i); family = family ? family[1] : "";
var values = decl.val.match(/\s*(?:\s*(caption|icon|menu|message-box|small-caption|status-bar)){1}/i); values = values ? values[1] : "";

除非我尝试使用以下字符串，否则一切都按我想要的方式工作：

font: normal small-caps 120%/120% fantasy, sans-serif;

这会导致样式，变体，重量和高度的值都设置为正常值：

style --> "normal"
variant --> "normal"
weight --> "normal"
height --> "normal"

这是因为正则表达式匹配每种情况下的第一个实例，并且不检查以确保它没有应该采取的其他值。它应该是：

style --> "normal"
variant --> "small-caps"
weight --> "120%"
height -->

我希望这是有道理的。如果您有任何疑问，请随时发表评论。谢谢你的帮助！

Answer 1

重量和尺寸之间存在一些正向斜线的问题但是你最好把它组合成一个正则表达式来制作除了
之外的所有内容锚可选。这样可以解决问题，你不会以正常的方式结束在大多数的变种上。

修改根据此参考http://www.w3schools.com/cssref/pr_font_font.asp
这是他们解析CSS字体速记属性的方法。

edit2 将硬空间分隔符调整为可选部分之后以及所需部分之间。

 #  /(?:(?:(normal|italic|oblique|initial|inherit)\s+)?(?:(normal|small-caps|initial|inherit)\s+)?(?:((?:normal|bold|bolder|lighter|initial|inherit|\d+))\s+)?(?:(smaller|small|x-small|xx-small|medium|larger|large|x-large|xx-large|initial|inherit|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px))(?:\/(normal|initial|inherit|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px)))?\s+)(?:(initial|inherit|(?:"[^"]*"|'[^']*'|[a-zA-Z-]+)(?:\s*,\s*(?:"[^"]*"|'[^']*'|[a-zA-Z-]+))*))|(caption|icon|menu|message-box|small-caption|status-bar|initial|inherit))/

 ####  CSS - Font Shorthand Property  
 ####  Reference:  http://www.w3schools.com/cssref/pr_font_font.asp    
 #### --------------------------------
 #### font:     

 (?:
      #### User Defined Fonts
      #### ------------------

      ##### Style (optional)
      (?:
           (                        # (1 start), Style
                normal
             |  italic
             |  oblique
             |  initial
             |  inherit 
           )                        # (1 end)
           \s+   # delimiter
      )?

      ##### Variant (optional)
      (?:
           (                        # (2 start), Variant
                normal
             |  small-caps
             |  initial
             |  inherit 
           )                        # (2 end)
           \s+   # delimiter
      )?

      ##### Weight (optional)
      (?:
           (                        # (3 start), Weight
                (?:
                     normal
                  |  bold
                  |  bolder
                  |  lighter
                  |  initial
                  |  inherit 
                  |  \d+ 
                )
           )                        # (3 end)
           \s+   # delimiter
      )?

      ##### Size (required)
      (?:
           (                        # (4 start), Size
                smaller
             |  small
             |  x-small
             |  xx-small
             |  medium
             |  larger
             |  large
             |  x-large
             |  xx-large
             |  initial
             |  inherit
             |  \d+ 
                (?: \% | in | cm | mm | em | rem | ex | pt | pc | px )
           )                        # (4 end)

           #####  Line Height (optional)
           (?:
                /                   # Separator
                (                   # (5 start), Line height
                     normal
                  |  initial
                  |  inherit
                  |  \d+ 
                     (?: \% | in | cm | mm | em | rem | ex | pt | pc | px )
                )                   # (5 end)

           )?

           \s+   # delimiter 
      )

      ##### Family (required)
      (?:
           (                        # (6 start), Family
                initial
             |  inherit
             |  (?: " [^"]* " | ' [^']* ' | [a-zA-Z-]+ )
                (?:
                     \s* , \s* 
                     (?: " [^"]* " | ' [^']* ' | [a-zA-Z-]+ )
                )*
           )                        # (6 end)
      )

   |  

      #### OR, 
      #### Use the Fonts used by these OS elements
      #### ------------------

      #### Values (required, if used)
      (                             # (7 start), Use values
           caption
        |  icon
        |  menu
        |  message-box
        |  small-caption
        |  status-bar
        |  initial
        |  inherit
      )                             # (7 end)
 )

Perl测试用例

$str = 'font:normal small-caps 120%/120% "Times New Roman", sans-serif;';

if ( $str =~ /(?:(?:(normal|italic|oblique|initial|inherit)\s+)?(?:(normal|small-caps|initial|inherit)\s+)?(?:((?:normal|bold|bolder|lighter|initial|inherit|\d+))\s+)?(?:(smaller|small|x-small|xx-small|medium|larger|large|x-large|xx-large|initial|inherit|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px))(?:\/(normal|initial|inherit|\d+(?:\%|in|cm|mm|em|rem|ex|pt|pc|px)))?\s+)(?:(initial|inherit|(?:"[^"]*"|'[^']*'|[a-zA-Z-]+)(?:\s*,\s*(?:"[^"]*"|'[^']*'|[a-zA-Z-]+))*))|(caption|icon|menu|message-box|small-caption|status-bar|initial|inherit))/)
{
    print "\nmatched  '$&'\n\n";
    print "style   = '$1'\n";
    print "variant = '$2'\n";
    print "weight  = '$3'\n";
    print "size    = '$4'\n";
    print "height  = '$5'\n";
    print "family  = '$6'\n";
    print "values  = '$7'\n";
}

输出＆gt;＆gt;

matched  'normal small-caps 120%/120% "Times New Roman", sans-serif'

style   = 'normal'
variant = 'small-caps'
weight  = ''
size    = '120%'
height  = '120%'
family  = '"Times New Roman", sans-serif'
values  = ''

Answer 2

您可以做的是：

找到一个属性后，从字符串中删除此属性。然后在修改后的字符串中搜索下一个属性。

这是字符串中第一个属性的示例：

var str = decl.val;

function removeFromString(str, result) {
    console.log(result);
    return str.slice(0, result.index) + str.slice(result.index + result[0].length);
}

var style = str.match(/\s*(?:\s*(normal|italic|oblique)){1}/i); 
if(style) {
    str = removeFromString(str, style);
}
style = style ? style[1] : "";

我为此做了 jsFiddle 。

根据展示正则表达式区分相似值

2 个答案: