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std::regex_token_iterator

From cppreference.com
< cpp‎ | regex
 
 
 
Regular expressions library
Classes
(C++11)
Algorithms
Iterators
regex_token_iterator
(C++11)
Exceptions
Traits
Constants
(C++11)
Regex Grammar
 
 
Defined in header <regex>
template<

    class BidirIt,
    class CharT = typename std::iterator_traits<BidirIt>::value_type,
    class Traits = std::regex_traits<CharT>

> class regex_token_iterator
(since C++11)

std::regex_token_iterator is a read-only LegacyForwardIterator that accesses the individual sub-matches of every match of a regular expression within the underlying character sequence. It can also be used to access the parts of the sequence that were not matched by the given regular expression (e.g. as a tokenizer).

On construction, it constructs an std::regex_iterator and on every increment it steps through the requested sub-matches from the current match_results, incrementing the underlying std::regex_iterator when incrementing away from the last submatch.

The default-constructed std::regex_token_iterator is the end-of-sequence iterator. When a valid std::regex_token_iterator is incremented after reaching the last submatch of the last match, it becomes equal to the end-of-sequence iterator. Dereferencing or incrementing it further invokes undefined behavior.

Just before becoming the end-of-sequence iterator, a std::regex_token_iterator may become a suffix iterator, if the index -1 (non-matched fragment) appears in the list of the requested submatch indices. Such iterator, if dereferenced, returns a match_results corresponding to the sequence of characters between the last match and the end of sequence.

A typical implementation of std::regex_token_iterator holds the underlying std::regex_iterator, a container (e.g. std::vector<int>) of the requested submatch indices, the internal counter equal to the index of the submatch, a pointer to std::sub_match, pointing at the current submatch of the current match, and a std::match_results object containing the last non-matched character sequence (used in tokenizer mode).

Contents

[edit] Type requirements

-
BidirIt must meet the requirements of LegacyBidirectionalIterator.

[edit] Specializations

Several specializations for common character sequence types are defined:

Defined in header <regex>
Type Definition
std::cregex_token_iterator std::regex_token_iterator<const char*>
std::wcregex_token_iterator std::regex_token_iterator<const wchar_t*>
std::sregex_token_iterator std::regex_token_iterator<std::string::const_iterator>
std::wsregex_token_iterator std::regex_token_iterator<