正则表达式来解析任意深度的功能 [英] Regex to parse functions with arbitrary depth
问题描述
我解析一个简单的语言(Excel公式)为其中所包含的功能。函数名称必须与任何字母,后面跟上任意数量的字母/数字,并以开放的括号(中间无空格)结束。例如 MYFUNC(
,此功能可以包含任何参数,包括其他的功能,并且必须以密切括号结束)
。当然,括号内的数学允许 = MYFUNC((1 + 1))
和(1 + 1)
不该'T是因为它没有我刚才所描述的功能规则检测为一个功能。我的目标是要认识到最高水平的函数调用的公式,找出函数名,提取参数。随着争论,我可以递归地寻找其他的函数调用。
使用此教程我砍死了下面的正则表达式。无似乎做的伎俩。他们都失败的测试用例粘贴下面。
本的应该的工作,但完全失败:
<$p$p><$c$c>(?<name>[a-z][a-z0-9]*\()(?<body>(?>[a-z][a-z0-9]*\((?<DEPTH>)|\)(?<-DEPTH>)|.?)*(?(DEPTH)(?!)))\)这适用于许多测试案例,但失败下面的测试案例。我不认为它处理嵌套函数法正确,它只是看起来开放括号/排料接近括号:
<$p$p><$c$c>(?<name>[a-z][a-z0-9]*\()(?<body>(?>\((?<DEPTH>)|\)(?<-DEPTH>)|.?)*(?(DEPTH)(?!)))\)下面是打破他们所有的测试:
<$p$p><$c$c>=Date(Year(A$5),Month(A$5),1)-(Weekday(Date(Year(A$5),Month(A$5),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1这应该匹配为:
日期(ARGUMENTS1)
平日(ARGUMENTS2)
其中ARGUMENTS2 =日期(年(A $ 5),月(A $ 5),1)
相反,它匹配:
ARGUMENTS2 =日期(年(A $ 5),月(A $ 5),1)-1)
我使用.NET正则表达式,它提供了对外部存储器。
这是完全在.NET正则表达式的能力。这里有一个工作演示:
使用系统;
使用System.Text.RegularEx pressions;
命名空间测试
{
类测试
{
公共静态无效的主要()
{
正则表达式R =新的正则表达式(@
(小于?名称&gt; [A-Z] [一个-Z0-9] * \()
(小于?体&GT;
?(大于
\((&LT;深度GT;)
|
\)(小于?-depth&GT)
|
[^()] +
)*
(?(深度)(?!))
)
\),RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
字符串公式= @"=Date(Year(A$5),Month(A$5),1)-(Weekday(Date(Year((A$5+1)),Month(A$5),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1";
的foreach(在r.Matches赛米(公式))
{
Console.WriteLine({0} \ N,m.Value);
}
}
}
}
输出:
的日期(年(A $ 5),月(A $ 5),1) 平日(日期(年((A $ 5 + 1)),月(A $ 5),1))
你的正则表达式的主要问题是,你是包括函数名称作为递归比赛的一部分 - 例如:
名1(...名称2(...)...)
任何开放的括号,这是叫不上名字pceded $ P $没有被计算在内,因为它是匹配的最后一种选择, | <?/ code>),并扔了与近距离括号的平衡。这也意味着,你不能匹配像
= MYFUNC公式((1 + 1))
,你在文中提到,但没有包括在本例中。 (我扔在一组额外的括号来证明的。)
编辑:这是与非显著,引用括号支持的版本:
正则表达式R =新的正则表达式(@
(小于?名称&gt; [A-Z] [一个-Z0-9] * \()
(小于?体&GT;
?(大于
\((&LT;深度GT;)
|
\)(小于?-depth&GT)
|
[^] +
|
[^()] +
)*
(?(深度)(?!))
)
\),RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
I'm parsing a simple language (Excel formulas) for the functions contained within. A function name must start with any letter, followed by any number of letters/numbers, and ending with an open paren (no spaces in between). For example MyFunc(
. The function can contain any arguments, including other functions and must end with a close paren )
. Of course, math within parens is allowed =MyFunc((1+1))
and (1+1)
shouldn't be detected as a function because it fails the function rule I've just described. My goal is to recognize the highest level function calls in a formula, identify the function name, extract the arguments. With the arguments, I can recursively look for other function calls.
Using this tutorial I hacked up the following regexes. None seem to do the trick. They both fail on test case pasted below.
This should work but completely fails:
(?<name>[a-z][a-z0-9]*\()(?<body>(?>[a-z][a-z0-9]*\((?<DEPTH>)|\)(?<-DEPTH>)|.?)*(?(DEPTH)(?!)))\)
This works for many test cases, but fails for test case below. I don't think it handles nested functions correctly- it just looks for open paren/close paren in the nesting:
(?<name>[a-z][a-z0-9]*\()(?<body>(?>\((?<DEPTH>)|\)(?<-DEPTH>)|.?)*(?(DEPTH)(?!)))\)
Here's the test that breaks them all:
=Date(Year(A$5),Month(A$5),1)-(Weekday(Date(Year(A$5),Month(A$5),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1
This should be matched as:
Date(ARGUMENTS1)
Weekday(ARGUMENTS2)
Where ARGUMENTS2 = Date(Year(A$5),Month(A$5),1)
Instead it matches:
ARGUMENTS2 = Date(Year(A$5),Month(A$5),1)-1)
I am using .net RegEx which provides for external memory.
This is well within the capabilities of .NET regexes. Here's a working demo:
using System;
using System.Text.RegularExpressions;
namespace Test
{
class Test
{
public static void Main()
{
Regex r = new Regex(@"
(?<name>[a-z][a-z0-9]*\()
(?<body>
(?>
\((?<DEPTH>)
|
\)(?<-DEPTH>)
|
[^()]+
)*
(?(DEPTH)(?!))
)
\)", RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
string formula = @"=Date(Year(A$5),Month(A$5),1)-(Weekday(Date(Year((A$5+1)),Month(A$5),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1";
foreach (Match m in r.Matches(formula))
{
Console.WriteLine("{0}\n", m.Value);
}
}
}
}
output:
Date(Year(A$5),Month(A$5),1) Weekday(Date(Year((A$5+1)),Month(A$5),1))
The main problem with your regex was that you were including the function name as part of the recursive match--for example:
Name1(...Name2(...)...)
Any open-paren that wasn't preceded by name was not counted, because it was matched by the final alternative, |.?
), and that threw off the balance with the close-parens. That also meant that you couldn't match formulas like =MyFunc((1+1))
, which you mentioned in the text but didn't include in the example. (I threw in an extra set of parens to demonstrate.)
EDIT: Here's the version with support for non-significant, quoted parens:
Regex r = new Regex(@"
(?<name>[a-z][a-z0-9]*\()
(?<body>
(?>
\((?<DEPTH>)
|
\)(?<-DEPTH>)
|
""[^""]+""
|
[^()""]+
)*
(?(DEPTH)(?!))
)
\)", RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
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