sindresorhus / regex

🔤 Swifty regular expressions

Regex

Swifty regular expressions

This is a wrapper for NSRegularExpression that makes it more convenient and type-safe to use regular expressions in Swift.

Install

Add the following to Package.swift:

.package(url: "https://github.com/sindresorhus/Regex", from: "0.1.0")

Or add the package in Xcode.

Usage

First, import the package:

import Regex

Supported regex syntax.

Examples

Check if it matches:

Regex(#"\d+"#).isMatched(by: "123")
//=> true

Get first match:

Regex(#"\d+"#).firstMatch(in: "123-456")?.value
//=> "123"

Get all matches:

Regex(#"\d+"#).allMatches(in: "123-456").map(\.value)
//=> ["123", "456"]

Replacing first match:

"123🦄456".replacingFirstMatch(of: #"\d+"#, with: "")
//=> "🦄456"

Replacing all matches:

"123🦄456".replacingAllMatches(of: #"\d+"#, with: "")
//=> "🦄"

Named capture groups:

let regex = Regex(#"\d+(?<word>[a-z]+)\d+"#)

regex.firstMatch(in: "123unicorn456")?.group(named: "word")?.value
//=> "unicorn"

Pattern matching:

switch "foo123" {
case Regex(#"^foo\d+$"#):
	print("Match!")
default:
	break
}

switch Regex(#"^foo\d+$"#) {
case "foo123":
	print("Match!")
default:
	break
}

Multiline and comments:

let regex = Regex(
	#"""
	^
	[a-z]+  # Match the word
	\d+     # Match the number
	$
	"""#,
	options: .allowCommentsAndWhitespace
)

regex.isMatched(by: "foo123")
//=> true

API

See the API docs.

FAQ

Why are pattern strings wrapped in #?

Those are raw strings and they make it possible to, for example, use \d without having to escape the backslash.

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regex's Issues

Strongly-typed regex named groups

Just an idea (untested):

struct Result: Codable {
	let word: String?
	let number: Int?
}

let regex = Regex(#"\d+(?<\#(.word)>[a-z]+)(?<\#(.number)>\d+)"#, type: Result.self)

let groups = regex.firstMatch(in: "123unicorn456")?.namedGroups

print(groups.word)
//=> Optional("unicorn")

print(groups.number)
//=> Optional(456)
//             ^ Int

Feedback wanted!

Improve print output

The output when printing Regex, Match, and Group is a bit messy. Would be nice to add some nice representations for them. For example, Regex could have the output /foo/i, where the i comes from the .caseInsensitive option.

Expected a macro identifier for a pound literal expression

I'm trying something similar to the doc's

 "123🦄456".replacingFirstMatch(of: #"\d+"#, with: "")
//=> "🦄456"

But I get a build error:

Make it Codable

Could be useful to make Regex Codable, but not something I need right now. PR welcome if you need it.

It needs to serialize both the expression and also the regex options.

Add `Regex#namedGroups`?

There's currently a method Regex#group(named:) to get a single named group, but it might be nicer to just add Regex#namedGroups which would be a [String: Group] of group name and group.

Thoughts?