Function StringRegexFind

sdk/add_on/scriptstdstring/scriptstdstring.cpp:383–422

This function returns the index of the first position that matches the regular expression AngelScript signature: int string::regexFind(const string &in regex, uint start = 0, uint &out lengthOfMatch = void)

// AngelScript signature:
// int string::regexFind(const string &in regex, uint start = 0, uint &out lengthOfMatch = void)
static int StringRegexFind(const string& rex, asUINT start, asUINT& outLengthOfMatch, const string& str)
{
	if (start >= str.length())
	{
		outLengthOfMatch = 0;
		return -1;
	}

	// TODO: If possible add support for matching utf8 characters
	// However on with MSVC it doesn't seem that std::regex works with utf8
	// This works with MSVC, but I don't want to have to convert the string to UTF-16 first because the position and length will not work
	// https://www.regular-expressions.info/stdregex.html
	// 
	//  std::wregex pattern(L"[[:alpha:]]+");
	//  bool result = std::regex_match(std::wstring(L"abcd�fg"), pattern);
	//
	// The solution from stack overflow doesn't work with MSVC
	// https://stackoverflow.com/questions/11254232/do-c11-regular-expressions-work-with-utf-8-strings
	// 
	//  std::locale old;
	//  std::locale::global(std::locale("en_US.UTF-8"));
	//  std::regex pattern("[[:alpha:]]+", std::regex_constants::extended);
	//  bool result = std::regex_match(std::string(u8"abcd�fg"), pattern);
	//
	// I've tried setting the manifest to use utf8 code page but it also doesn't work with MSVC
	// https://learn.microsoft.com/en-us/windows/apps/design/globalizing/use-utf8-code-page

	std::regex pattern(rex, std::regex_constants::ECMAScript | std::regex_constants::collate);
	std::cmatch match;
	bool result = std::regex_search(str.c_str() + start, str.c_str()+str.length(), match, pattern);

	if (!result)
	{
		outLengthOfMatch = 0;
		return -1;
	}

	outLengthOfMatch = (asUINT)match[0].length();
	return (int)match.prefix().length();
}

// This function returns the index of the first position where the one of the bytes in substring
// exists in the input string. If the characters in the substring doesn't exist in the input