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version 2.109.1

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std.regex.Regex/regex - multiple declarations

Function regex

Compile regular expression pattern for the later execution.

auto regex(S, C) (
  const S[] patterns,
  const(char)[] flags = ""
) @trusted
if (isSomeString!S);

auto regex(S) (
  S pattern,
  const(char)[] flags = ""
) @trusted
if (isSomeString!S);

Returns

Regex object that works on inputs having the same character width as pattern.

Parameters

NameDescription
pattern A single regular expression to match.
patterns An array of regular expression strings. The resulting Regex object will match any expression; use whichPattern to know which.
flags The attributes (g, i, m, s and x accepted)

Throws

RegexException if there were any errors during compilation.

Example

void test(S)()
{
    // multi-pattern regex example
    S[] arr = [`([a-z]+):(\d+)`, `(\d+),\d+`];
    auto multi = regex(arr); // multi regex
    S str = "abc:43 12,34";
    auto m = str.matchAll(multi);
    writeln(m.front.whichPattern); // 1
    writeln(m.front[1]); // "abc"
    writeln(m.front[2]); // "43"
    m.popFront();
    writeln(m.front.whichPattern); // 2
    writeln(m.front[1]); // "12"
}

import std.meta : AliasSeq;
static foreach (C; AliasSeq!(string, wstring, dstring))
    // Test with const array of patterns - see https://issues.dlang.org/show_bug.cgi?id=20301
    static foreach (S; AliasSeq!(C, const C, immutable C))
        test!S();

Alias Regex

Regex object holds regular expression pattern in compiled form.

alias Regex(Char) = std.regex.internal.ir.Regex!Char;

Instances of this object are constructed via calls to regex. This is an intended form for caching and storage of frequently used regular expressions.

Example

Test if this object doesn't contain any compiled pattern. 

Regex!char r;
assert(r.empty);
r = regex(""); // Note: "" is a valid regex pattern.
assert(!r.empty);

Getting a range of all the named captures in the regex. 

import std.range;
import std.algorithm;

auto re = regex(`(?P<name>\w+) = (?P<var>\d+)`);
auto nc = re.namedCaptures;
static assert(isRandomAccessRange!(typeof(nc)));
assert(!nc.empty);
assert(nc.length == 2);
assert(nc.equal(["name", "var"]));
assert(nc[0] == "name");
assert(nc[1..$].equal(["var"]));

Authors

Dmitry Olshansky,

API and utility constructs are modeled after the original std.regex by Walter Bright and Andrei Alexandrescu.

License

Boost License 1.0.