在c项目中使用pcre2

我正在寻找在我的简单c应用程序中使用pcre2,(我正在使用vs2015).
(我正在看各种正则表达式库,一般的感觉是pcre / pcre2是最灵活的)

首先我从官方位置(http://sourceforge.net/projects/pcre/files/pcre2/10.20/)下载了pcre2并创建了一个非常简单的例子.@H_404_4@

#define PCRE2_CODE_UNIT_WIDTH 8
#include <pcre2.h>
...
PCRE2_SPTR subject = (PCRE2_SPTR)std::string("this is it").c_str();
PCRE2_SPTR pattern = (PCRE2_SPTR)std::string("([a-z]+)|\\s").c_str();

...
int errorcode;
PCRE2_SIZE erroroffset;
pcre2_code *re = pcre2_compile(pattern,PCRE2_ZERO_TERMINATED,PCRE2_ANCHORED | PCRE2_UTF,&errorcode,&erroroffset,NULL);
...

首先文件“pcre2.h”不存在,所以我将pcre2.h.generic重命名为pcre2.h@H_404_4@

但后来我得到了未解析的外部链接错误.@H_404_4@

我猜我需要从源到项目包含一个或多个文件.
但我不愿意随意添加文件而不知道它们的作用.@H_404_4@

有人可以给出一些简单的步骤来使用pcre2成功构建项目吗?@H_404_4@

UPDATE
这不是一个导入库问题,pcre2.h没有附带librar(不是我在其发布位置可以看到的那个).@H_404_4@

解决方法

如果你不介意使用包装器,这是我的: JPCRE2

您需要根据要使用的字符串类(分别为std :: string,std :: wstring,std :: u16string,std :: u32string)选择基本字符类型(char,wchar_t,char16_t,char32_t):@H_404_4@

typedef jpcre2::select<char> jp;
//Selecting char as the basic character type will require
//8 bit PCRE2 library where char is 8 bit,//or 16 bit PCRE2 library where char is 16 bit,//or 32 bit PCRE2 library where char is 32 bit.
//If char is not 8,16 or 32 bit,it's a compile error.

匹配示例:@H_404_4@

检查字符串是否与模式匹配:@H_404_4@

if(jp::Regex("(\\d)|(\\w)").match("I am the subject")) 
    std::cout<<"\nmatched";
else
    std::cout<<"\nno match";

匹配所有并获得匹配计数:@H_404_4@

size_t count = 
jp::Regex("(\\d)|(\\w)","mi").match("I am the subject","g");
// 'm' modifier enables multi-line mode for the regex
// 'i' modifier makes the regex case insensitive
// 'g' modifier enables global matching

获取编号的子字符串/捕获的组:@H_404_4@

jp::VecNum vec_num;
count = 
jp::Regex("(\\w+)\\s*(\\d+)","im").initMatch()
                                  .setSubject("I am 23,I am digits 10")
                                  .setModifier("g")
                                  .setNumberedSubstringVector(&vec_num)
                                  .match();
std::cout<<"\nTotal match of first match: "<<vec_num[0][0];      
std::cout<<"\nCaptrued group 1 of first match: "<<vec_num[0][1]; 
std::cout<<"\nCaptrued group 2 of first match: "<<vec_num[0][2]; 

std::cout<<"\nTotal match of second match: "<<vec_num[1][0];
std::cout<<"\nCaptrued group 1 of second match: "<<vec_num[1][1];
std::cout<<"\nCaptrued group 2 of second match: "<<vec_num[1][2];

获取命名的子串/捕获组:@H_404_4@

jp::VecNas vec_nas;
count = 
jp::Regex("(?<word>\\w+)\\s*(?<digit>\\d+)","m")
                         .initMatch()
                         .setSubject("I am 23,I am digits 10")
                         .setModifier("g")
                         .setNamedSubstringVector(&vec_nas)
                         .match();
std::cout<<"\nCaptured group (word) of first match: "<<vec_nas[0]["word"];
std::cout<<"\nCaptured group (digit) of first match: "<<vec_nas[0]["digit"];

std::cout<<"\nCaptured group (word) of second match: "<<vec_nas[1]["word"];
std::cout<<"\nCaptured group (digit) of second match: "<<vec_nas[1]["digit"];

迭代所有匹配和子串:@H_404_4@

//Iterating through numbered substring
for(size_t i=0;i<vec_num.size();++i){
    //i=0 is the first match found,i=1 is the second and so forth
    for(size_t j=0;j<vec_num[i].size();++j){
        //j=0 is the capture group 0 i.e the total match
        //j=1 is the capture group 1 and so forth.
        std::cout<<"\n\t("<<j<<"): "<<vec_num[i][j]<<"\n";
    }
}

替换/替换示例:@H_404_4@

std::cout<<"\n"<<
///replace all occurrences of a digit with @
jp::Regex("\\d").replace("I am the subject string 44","@","g");

///swap two parts of a string
std::cout<<"\n"<<
jp::Regex("^([^\t]+)\t([^\t]+)$")
             .initReplace()
             .setSubject("I am the subject\tTo be swapped according to tab")
             .setReplaceWith("$2 $1")
             .replace();

替换为匹配评估器:@H_404_4@

jp::String callback1(const jp::NumSub& m,void*,void*){
    return "("+m[0]+")"; //m[0] is capture group 0,i.e total match (in each match)
}
int main(){
    jp::Regex re("(?<total>\\w+)","n");
    jp::RegexReplace rr(&re);
    String s3 = "I am ঋ আা a string 879879 fdsjkll ১ ২ ৩ ৪ অ আ ক খ গ ঘ আমার সোনার বাংলা";
    rr.setSubject(s3)
      .setPcre2Option(PCRE2_SUBSTITUTE_GLOBAL);
    std::cout<<"\n\n### 1\n"<<
            rr.nreplace(jp::MatchEvaluator(callback1));
            //nreplace() treats the returned string from the callback as literal,//while replace() will process the returned string
            //with pcre2_substitute()

    #if __cplusplus >= 201103L
    //example with lambda
    std::cout<<"\n\n### Lambda\n"<<
            rr.nreplace(
                jp::MatchEvaluator(
                    [](const jp::NumSub& m1,const jp::MapNas& m2,void*){
                        return "("+m1[0]+"/"+m2.at("total")+")";
                    }
                ));
    #endif
    return 0;
}

您可以阅读完整的文档here.@H_404_4@

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