在编程的过程中,尤其是文本的处理,我们很多时候都需要正则表达式,比如,验证用户输入的Email是否格式正确,电话号码是否符合规范,或者其他的自定义规则。对新手来说,熟记正则表达式的规则比较困难,那么有没有一种更符合自然语义的正则表达式呢,本文会
在编程的过程中,尤其是文本的处理,我们很多时候都需要正则表达式,比如,验证用户输入的Email是否格式正确,电话号码是否符合规范,或者其他的自定义规则。对新手来说,熟记正则表达式的规则比较困难,那么有没有一种更符合自然语义的正则表达式呢,本文会给你答案。
Most newbie and some seasoned) programmers have difficultly constructing Regular Expressions. Many a times one needs to create a Regexp quickly to test a a particular piece of code. However, not being comfortable withe Regexps can be a problem.?VerbalExpressions?is a PHP library that enables you to construct regular expressions using natural language like constructs. Think of it like a DSL for building Regexps.
verbalexpressions 已经实现了多个语言版本的库,可以从这里得到。
Below is a sample PHP code that constructs a regular expression which tests whether a given string is a valid url.
如下示例用来测试给定的一个string是否是有效的url地址。
startOfLine) ->then"http") ->maybe"s") ->then"://") ->maybe"www.") ->anythingBut" ") ->endOfLine); if$regex->test"http://www.codediesel.com")) echo "valid url"; else echo "invalid url"; ?>
The main part of the code the DSL like interface that helps you build a Regexp.
$regex ->startOfLine) ->then"http") ->maybe"s") ->then"://") ->maybe"www.") ->anythingBut" ") ->endOfLine);
If you want to see what regular expression the code has built, we can use the?getRegex function of the class.
startOfLine) ->then"http") ->maybe"s") ->then"://") ->maybe"www.") ->anythingBut" ") ->endOfLine); echo $regex->getRegex);
This will print the Regexp given below.
打印输出正则表达式。
/^http)s)?\:\/\/)www\.)?[^ ]*)$/m
We can now use the above Regexp in our code to accomplish the same thing as above.
$myRegexp = '/^http)s)?\:\/\/)www\.)?[^ ]*)$/m'; if preg_match$myRegexp, 'http://www.codediesel.com')) { echo 'valid url'; } else { echo 'invalud url'; }
We can also use the?$regex?object given in the above example directly in our code where the particular Regexp is required.
可以使用函数 getRegex 获取正则表达式规则,或者直接可以用 $regex 对象,库内部已经实现了转换。
内部的转换函数:
/** * Object to string * * PHP Magic method to return a string representation of the object. * * @access public * @return string */ ????public function __toString) ????{ ????????return $this->getRegex); ????}
include_once'VerbalExpressions.php'); $regex = new VerEx; $regex ->startOfLine) ->then"http") ->maybe"s") ->then"://") ->maybe"www.") ->anythingBut" ") ->endOfLine); if preg_match$regex, 'http://www.codediesel.com')) { echo 'valid url'; } else { echo 'invalud url'; }
The PHP version of VerbalExpressions is a port of the original JavaScript version,JSVerbalExpressions. Additional modifiers that will help you build regular expressions can be found?here.
文章节选:constructing-hard-regular-expressions-with-verbalexpressions
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