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|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2002-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package reflect
package internal
package util
import java.lang.System.{lineSeparator => EOL}
/** This object provides utility methods to extract elements
* from Strings.
*
* @author Martin Odersky
* @version 1.0
*/
trait StringOps {
def oempty(xs: String*) = xs filterNot (x => x == null || x == "")
def ojoin(xs: String*): String = oempty(xs: _*) mkString " "
def longestCommonPrefix(xs: List[String]): String = xs match {
case Nil => ""
case w :: Nil => w
case _ =>
def lcp(ss: List[String]): String = {
val w :: ws = ss
if (w == "") ""
else if (ws exists (s => s == "" || (s charAt 0) != (w charAt 0))) ""
else w.substring(0, 1) + lcp(ss map (_ substring 1))
}
lcp(xs)
}
/** Like String#trim, but trailing whitespace only.
*/
def trimTrailingSpace(s: String): String = {
var end = s.length
while (end > 0 && s.charAt(end - 1).isWhitespace)
end -= 1
if (end == s.length) s
else s.substring(0, end)
}
/** Breaks the string into lines and strips each line before reassembling. */
def trimAllTrailingSpace(s: String): String = s.lines.map(trimTrailingSpace).mkString(EOL)
def decompose(str: String, sep: Char): List[String] = {
def ws(start: Int): List[String] =
if (start == str.length) List()
else if (str.charAt(start) == sep) ws(start + 1)
else {
val end = str.indexOf(sep, start)
if (end < 0) List(str.substring(start))
else str.substring(start, end) :: ws(end + 1)
}
ws(0)
}
def words(str: String): List[String] = decompose(str, ' ')
def splitWhere(str: String, f: Char => Boolean, doDropIndex: Boolean = false): Option[(String, String)] =
splitAt(str, str indexWhere f, doDropIndex)
def splitAt(str: String, idx: Int, doDropIndex: Boolean = false): Option[(String, String)] =
if (idx == -1) None
else Some((str take idx, str drop (if (doDropIndex) idx + 1 else idx)))
/** Returns a string meaning "n elements".
* Don't try an element such as "index" with irregular plural.
*/
def countElementsAsString(n: Int, element: String): String =
n match {
case 0 => s"no ${element}s"
case 1 => s"one ${element}"
case _ => s"${countAsString(n)} ${element}s"
}
/** Turns a count into a friendly English description if n<=4.
* Otherwise, a scary math representation.
*/
def countAsString(n: Int): String =
n match {
case 0 => "none"
case 1 => "one"
case 2 => "two"
case 3 => "three"
case 4 => "four"
case _ => n.toString
}
}
object StringOps extends StringOps
|
