ScalaVerbalExpressions

import com.github.verbalexpressions.VerbalExpression
import VerbalExpression._

val validUrl = $.startOfLine()
                .andThen("http")
                .maybe("s")
                .andThen("://")
                .maybe("www.")
                .anythingBut(" ")
                .endOfLine()

assert("https://www.google.com" is validUrl)
assert("ftp://home.comcast.net" isNot validUrl)

For more methods, checkout the wiki and the source

The intention of self-documenting code is to replace comments with self-evident code. For example:

BAD (have to mental-parse regex and/or trust the comment):

val numberRegex = """(\Q-\E)?\d+((\Q.\E)\d+)?""" // negative sign followed by digits, followed by optional fraction part

GOOD (code describes what it is and assert in end to make sure no magic was done by the library):

val fraction = $.andThen(".").digits()
val number = $.maybe("-").digits().maybe(fraction)       // verbalexpressions can be composed
assert(number.regexp == numberRegex)

assert(Seq("3", "-4", "-0.458") forall number.check)
assert(Seq("0.", "hello", "4.3.2") forall number.notMatch)

Performance: As fast as vanilla regexes - the library is just a builder around a regex string. You can always access the underlying compiled Pattern:

val money = $.oneOf("$", "€", "₹", "¥").digits()    // works with symbols too
val pattern: java.util.regex.Pattern = money.compile    // the compiled pattern

sbt

Add the following to your build.sbt:

resolvers += "Sonatype releases" at "http://oss.sonatype.org/content/repositories/releases/"

libraryDependencies += "com.github.verbalexpressions" %% "ScalaVerbalExpressions" % "1.0.1"