问题：查找匹配的字符串并从匹配的字符串中提取数据。有许多命令字符串包含关键字和数据。
命令示例：
关键字：询问，通知，消息，来，那。数据：
输入字符串：
我的问题包括两个问题 1）找到匹配的命令 2）提取数据
这是我正在做的事情： 我创建了多个正则表达式： “问[[：s：]] [[：w：]] + [[：s：]]到[[：s：]] [[：w：]] +”或“问（[^ \ t \ N] +α）（[^ \吨\ n] +？）” “通知[[：s：]] [[：w：]] + [[：s：]] [[：s：]] [[：w：]] +”或“通知（[^ \ t \] N] +）指出（[^ \吨\ n] +？）“
void searchExpression(const char *regString)
{
std::string str;
boost::regex callRegEx(regString, boost::regex_constants::icase);
boost::cmatch im;
while(true) {
std::cout << "Enter String: ";
getline(std::cin, str);
fprintf(stderr, "str %s regstring %s\n", str.c_str(), regString);
if(boost::regex_search(str.c_str(), im, callRegEx)) {
int num_var = im.size() + 1;
fprintf(stderr, "Matched num_var %d\n", num_var);
for(int j = 0; j <= num_var; j++) {
fprintf(stderr, "%d) Found %s\n",j, std::string(im[j]).c_str());
}
}
else {
fprintf(stderr, "Not Matched\n");
}
}
}
我能够找到匹配的字符串，我无法提取数据。 这是输出：
input_string: Ask peter to call Regex Ask[[:s:]][[:w:]]+[[:s:]]to[[:s:]][[:w:]]+
Matched num_var 2
0) Found Ask peter to call
1) Found
2) Found
我想提起彼得并打电话给彼得打电话。
答案 0 :(得分：4)
由于你真的想要解析语法，你应该考虑Boost的解析器生成器。
你只需要自上而下地编写整个内容：
auto sentence = [](auto&& v, auto&& p) {
auto verb = lexeme [ no_case [ as_parser(v) ] ];
auto name = lexeme [ +graph ];
auto particle = lexeme [ no_case [ as_parser(p) ] ];
return confix(verb, particle) [ name ];
};
auto ask = sentence("ask", "to") >> lexeme[+char_];
auto notify = sentence("notify", "that") >> lexeme[+char_];
auto message = sentence("message", "that") >> lexeme[+char_];
auto command = ask | notify | message;
这是Spirit X3的语法。将lexeme读为“保持整个单词”（不要忽略空格）。
此处，“名称”被视为任何符合预期粒子的内容
如果您只想返回匹配的原始字符串，这就足够了：
<强> Live On Coliru
#include <iostream>
#include <boost/spirit/home/x3.hpp>
#include <boost/spirit/home/x3/directive/confix.hpp>
namespace x3 = boost::spirit::x3;
namespace commands {
namespace grammar {
using namespace x3;
auto sentence = [](auto&& v, auto&& p) {
auto verb = lexeme [ no_case [ as_parser(v) ] ];
auto name = lexeme [ +graph ];
auto particle = lexeme [ no_case [ as_parser(p) ] ];
return confix(verb, particle) [ name ];
};
auto ask = sentence("ask", "to") >> lexeme[+char_];
auto notify = sentence("notify", "that") >> lexeme[+char_];
auto message = sentence("message", "that") >> lexeme[+char_];
auto command = ask | notify | message;
auto parser = raw [ skip(space) [ command ] ];
}
}
int main() {
for (std::string const input : {
"Ask peter to call me",
"Notify Jenna that I am going to be away",
"Message home that I am running late",
})
{
std::string matched;
if (parse(input.begin(), input.end(), commands::grammar::parser, matched))
std::cout << "Matched: '" << matched << "'\n";
else
std::cout << "No match in '" << input << "'\n";
}
}
打印：
Matched: 'Ask peter to call me'
Matched: 'Notify Jenna that I am going to be away'
Matched: 'Message home that I am running late'
当然，您实际上想要提取相关信息。
以下是我的。让我们解析一个结构：
struct Command {
enum class Type { ask, message, notify } type;
std::string name;
std::string message;
};
让我们将main()写为：
commands::Command cmd;
if (parse(input.begin(), input.end(), commands::grammar::parser, cmd))
std::cout << "Matched: " << cmd.type << "|" << cmd.name << "|" << cmd.message << "\n";
else
std::cout << "No match in '" << input << "'\n";
<强> Live On Coliru
#include <iostream>
#include <boost/fusion/adapted/struct.hpp>
#include <boost/spirit/home/x3.hpp>
#include <boost/spirit/home/x3/directive/confix.hpp>
namespace x3 = boost::spirit::x3;
namespace commands {
struct Command {
enum class Type { ask, message, notify } type;
std::string name;
std::string message;
friend std::ostream& operator<<(std::ostream& os, Type t) { return os << static_cast<int>(t); } // TODO
};
}
BOOST_FUSION_ADAPT_STRUCT(commands::Command, type, name, message)
namespace commands {
namespace grammar {
using namespace x3;
auto sentence = [](auto type, auto&& v, auto&& p) {
auto verb = lexeme [ no_case [ as_parser(v) ] ];
auto name = lexeme [ +graph ];
auto particle = lexeme [ no_case [ as_parser(p) ] ];
return attr(type) >> confix(verb, particle) [ name ];
};
using Type = Command::Type;
auto ask = sentence(Type::ask, "ask", "to") >> lexeme[+char_];
auto notify = sentence(Type::notify, "notify", "that") >> lexeme[+char_];
auto message = sentence(Type::message, "message", "that") >> lexeme[+char_];
auto command // = rule<struct command, Command> { }
= ask | notify | message;
auto parser = skip(space) [ command ];
}
}
int main() {
for (std::string const input : {
"Ask peter to call me",
"Notify Jenna that I am going to be away",
"Message home that I am running late",
})
{
commands::Command cmd;
if (parse(input.begin(), input.end(), commands::grammar::parser, cmd))
std::cout << "Matched: " << cmd.type << "|" << cmd.name << "|" << cmd.message << "\n";
else
std::cout << "No match in '" << input << "'\n";
}
}
打印
Matched: 0|peter|call me
Matched: 2|Jenna|I am going to be away
Matched: 1|home|I am running late
¹我不是英语语言学家，所以我不知道这是否是正确的语法术语：）
答案 1 :(得分：2)
此代码从文件＆＃34; commands.txt＆＃34;中读取命令字符串，搜索正则表达式并在匹配时打印部件。
#include <iostream>
#include <fstream>
#include <string>
#include <boost/regex.hpp>
const int NumCmdParts = 4;
std::string CommandPartIds[] = {"Verb", "Name", "Preposition", "Content"};
int main(int argc, char *argv[])
{
std::ifstream ifs;
ifs.open ("commands.txt", std::ifstream::in);
if (!ifs.is_open()) {
std::cout << "Error opening file commands.txt" << std::endl;
exit(1);
}
std::string cmdStr;
// Pieces of regular expression pattern
// '(?<Verb>' : This is to name the capture group as 'Verb'
std::string VerbPat = "(?<Verb>(Ask)|(Notify|Message))";
std::string SeparatorPat = "\\s*";
std::string NamePat = "(?<Name>\\w+)";
// Conditional expression. if (Ask) (to) else (that)
std::string PrepositionPat = "(?<Preposition>(?(2)(to)|(that)))";
std::string ContentPat = "(?<Content>.*)";
// Put the pieces together to compose pattern
std::string TotalPat = VerbPat + SeparatorPat + NamePat + SeparatorPat
+ PrepositionPat + SeparatorPat + ContentPat;
boost::regex actions_re(TotalPat);
boost::smatch action_match;
while (getline(ifs, cmdStr)) {
bool IsMatch = boost::regex_search(cmdStr, action_match, actions_re);
if (IsMatch) {
for (int i=1; i <= NumCmdParts; i++) {
std::cout << CommandPartIds[i-1] << ": " << action_match[CommandPartIds[i-1]] << "\n";
}
}
}
ifs.close();
}