cppdraft_translate/cppdraft/re/alg/match.md

[re.alg.match]

28 Text processing library [text]

28.6 Regular expressions library [re]

28.6.10 Regular expression algorithms [re.alg]

28.6.10.2 regex_match [re.alg.match]

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template<class BidirectionalIterator, class Allocator, class charT, class traits> bool regex_match(BidirectionalIterator first, BidirectionalIterator last, match_results<BidirectionalIterator, Allocator>& m, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Preconditions: BidirectionalIterator modelsbidirectional_iterator ([iterator.concept.bidir]).

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Effects: Determines whether there is a match between the regular expression e, and all of the character sequence [first, last).

The parameter flags is used to control how the expression is matched against the character sequence.

When determining if there is a match, only potential matches that match the entire character sequence are considered.

Returns true if such a match exists, false otherwise.

[Example 1: std::regex re("Get|GetValue"); std::cmatch m; regex_search("GetValue", m, re); // returns true, and m[0] contains "Get" regex_match ("GetValue", m, re); // returns true, and m[0] contains "GetValue" regex_search("GetValues", m, re); // returns true, and m[0] contains "Get" regex_match ("GetValues", m, re); // returns false — end example]

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Postconditions: m.ready() == true in all cases.

If the function returns false, then the effect on parameter m is unspecified except that m.size() returns 0 and m.empty() returns true.

Otherwise the effects on parameter m are given in Table 123.

Table 123 — Effects of regex_match algorithm [tab:re.alg.match]

🔗 Element	Value
🔗 m.size()	1 + e.mark_count()
🔗 m.empty()	false
🔗 m.prefix().first	first
🔗 m.prefix().second	first
🔗 m.prefix().matched	false
🔗 m.suffix().first	last
🔗 m.suffix().second	last
🔗 m.suffix().matched	false
🔗 m[0].first	first
🔗 m[0].second	last
🔗 m[0].matched	true
🔗 m[n].first	For all integers 0 < n < m.size(), the start of the sequence that matched sub-expression n. Alternatively, if sub-expression n did not participate in the match, then last.
🔗 m[n].second	For all integers 0 < n < m.size(), the end of the sequence that matched sub-expression n. Alternatively, if sub-expression n did not participate in the match, then last.
🔗 m[n].matched	For all integers 0 < n < m.size(), true if sub-expression n participated in the match, false otherwise.

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template<class BidirectionalIterator, class charT, class traits> bool regex_match(BidirectionalIterator first, BidirectionalIterator last, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Effects: Behaves “as if” by constructing an instance ofmatch_results what, and then returning the result ofregex_match(first, last, what, e, flags).

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template<class charT, class Allocator, class traits> bool regex_match(const charT* str, match_results<const charT*, Allocator>& m, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Returns: regex_match(str, str + char_traits​::​length(str), m, e, flags).

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template<class ST, class SA, class Allocator, class charT, class traits> bool regex_match(const basic_string<charT, ST, SA>& s, match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Returns: regex_match(s.begin(), s.end(), m, e, flags).

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template<class charT, class traits> bool regex_match(const charT* str, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Returns: regex_match(str, str + char_traits​::​length(str), e, flags).

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template<class ST, class SA, class charT, class traits> bool regex_match(const basic_string<charT, ST, SA>& s, const basic_regex<charT, traits>& e, regex_constants::match_flag_type flags = regex_constants::match_default);

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Returns: regex_match(s.begin(), s.end(), e, flags).