substring

Very fast one-time string searches in Go. Simple and composable.

Interop with regexp for backwards compatibility (easy migration from your current system to substring).

Installation

The recommended way to install substring is by using go get:

go get github.com/toqueteos/substring

Go Modules are supported!

Examples

A basic example with two matchers:

package main

import (
	"fmt"
	"regexp"

	"github.com/toqueteos/substring/v2"
)

func main() {
	m1 := substring.After("assets/", substring.Or(
		substring.Has("jquery"),
		substring.Has("angular"),
		substring.Suffixes(".js", ".css", ".html"),
	))
	fmt.Println(m1.Match("assets/angular/foo/bar")) // Prints: true
	fmt.Println(m1.Match("assets/js/file.js"))      // Prints: true
	fmt.Println(m1.Match("assets/style/bar.css"))   // Prints: true
	fmt.Println(m1.Match("assets/foo/bar.html"))    // Prints: true
	fmt.Println(m1.Match("assets/js/qux.json"))     // Prints: false
	fmt.Println(m1.Match("core/file.html"))         // Prints: false
	fmt.Println(m1.Match("foobar/that.jsx"))        // Prints: false
	fmt.Println()

	m2 := substring.After("vendor/", substring.Suffixes(".css", ".js", ".less"))
	fmt.Println(m2.Match("foo/vendor/bar/qux.css")) // Prints: true
	fmt.Println(m2.Match("foo/var/qux.less"))       // Prints: false
	fmt.Println()

	re := regexp.MustCompile(`vendor\/.*\.(css|js|less)$`)
	fmt.Println(re.MatchString("foo/vendor/bar/qux.css")) // Prints: true
	fmt.Println(re.MatchString("foo/var/qux.less"))       // Prints: false
}

How fast?

It may vary depending on your use case but 1~2 orders of magnitude faster than regexp is pretty common.

Test it out for yourself by running go test -bench .!

$ go test -bench .
pkg: github.com/toqueteos/substring
BenchmarkExample1-16            30759529                38.4 ns/op
BenchmarkExample2-16            26659675                40.0 ns/op
BenchmarkExample3-16            30760317                37.7 ns/op
BenchmarkExample4-16            31566652                36.8 ns/op
BenchmarkExample5-16           123704845                9.70 ns/op
BenchmarkExampleRe1-16           2739574                 436 ns/op
BenchmarkExampleRe2-16           2494791                 480 ns/op
BenchmarkExampleRe3-16           1681654                 713 ns/op
BenchmarkExampleRe4-16           2205490                 540 ns/op
BenchmarkExampleRe5-16          19673001                55.0 ns/op
PASS
ok      github.com/toqueteos/substring  15.016s

License

MIT, see LICENSE