wneuper/isa: src/Pure/General/path.scala@0d2114eb412a

     1 /*  Title:      Pure/General/path.scala

     2     Author:     Makarius

     4 Algebra of file-system paths: basic POSIX notation, extended by named

     5 roots (e.g. //foo) and variables (e.g. $BAR).

     6 */

     8 package isabelle

    11 import java.io.{File => JFile}

    13 import scala.util.matching.Regex

    16 object Path

    17 {

    18   /* path elements */

    20   sealed abstract class Elem

    21   private case class Root(val name: String) extends Elem

    22   private case class Basic(val name: String) extends Elem

    23   private case class Variable(val name: String) extends Elem

    24   private case object Parent extends Elem

    26   private def err_elem(msg: String, s: String): Nothing =

    27     error (msg + " path element specification: " + quote(s))

    29   private def check_elem(s: String): String =

    30     if (s == "" || s == "~" || s == "~~") err_elem("Illegal", s)

    31     else

    32       s.iterator.filter(c => c == '/' || c == '\\' || c == '$' || c == ':').toList match {

    33         case Nil => s

    34         case bads =>

    35           err_elem ("Illegal character(s) " + commas_quote(bads.map(_.toString)) + " in", s)

    36       }

    38   private def root_elem(s: String): Elem = Root(check_elem(s))

    39   private def basic_elem(s: String): Elem = Basic(check_elem(s))

    40   private def variable_elem(s: String): Elem = Variable(check_elem(s))

    42   private def apply_elem(y: Elem, xs: List[Elem]): List[Elem] =

    43     (y, xs) match {

    44       case (Root(_), _) => List(y)

    45       case (Parent, Root(_) :: _) => xs

    46       case (Parent, Basic(_) :: rest) => rest

    47       case _ => y :: xs

    48     }

    50   private def norm_elems(elems: List[Elem]): List[Elem] =

    51     (elems :\ (Nil: List[Elem]))(apply_elem)

    53   private def implode_elem(elem: Elem): String =

    54     elem match {

    55       case Root("") => ""

    56       case Root(s) => "//" + s

    57       case Basic(s) => s

    58       case Variable(s) => "$" + s

    59       case Parent => ".."

    60     }

    63   /* path constructors */

    65   val current: Path = new Path(Nil)

    66   val root: Path = new Path(List(Root("")))

    67   def named_root(s: String): Path = new Path(List(root_elem(s)))

    68   def basic(s: String): Path = new Path(List(basic_elem(s)))

    69   def variable(s: String): Path = new Path(List(variable_elem(s)))

    70   val parent: Path = new Path(List(Parent))

    73   /* explode */

    75   private def explode_elem(s: String): Elem =

    76     if (s == "..") Parent

    77     else if (s == "~") Variable("USER_HOME")

    78     else if (s == "~~") Variable("ISABELLE_HOME")

    79     else if (s.startsWith("$")) variable_elem(s.substring(1))

    80     else basic_elem(s)

    82   private def explode_elems(ss: List[String]): List[Elem] =

    83     ss.filterNot(s => s.isEmpty || s == ".").map(explode_elem).reverse

    85   def explode(str: String): Path =

    86   {

    87     val ss = space_explode('/', str)

    88     val r = ss.takeWhile(_.isEmpty).length

    89     val es = ss.dropWhile(_.isEmpty)

    90     val (roots, raw_elems) =

    91       if (r == 0) (Nil, es)

    92       else if (r == 1) (List(Root("")), es)

    93       else if (es.isEmpty) (List(Root("")), Nil)

    94       else (List(root_elem(es.head)), es.tail)

    95     new Path(norm_elems(explode_elems(raw_elems) ++ roots))

    96   }

    98   def split(str: String): List[Path] =

    99     space_explode(':', str).filterNot(_.isEmpty).map(explode)

   100 }

   103 final class Path private(private val elems: List[Path.Elem]) // reversed elements

   104 {

   105   def is_current: Boolean = elems.isEmpty

   106   def is_absolute: Boolean = !elems.isEmpty && elems.last.isInstanceOf[Path.Root]

   107   def is_basic: Boolean = elems match { case List(Path.Basic(_)) => true case _ => false }

   109   def +(other: Path): Path = new Path((other.elems :\ elems)(Path.apply_elem))

   112   /* implode */

   114   def implode: String =

   115     elems match {

   116       case Nil => "."

   117       case List(Path.Root("")) => "/"

   118       case _ => elems.map(Path.implode_elem).reverse.mkString("/")

   119     }

   121   override def toString: String = quote(implode)

   124   /* base element */

   126   private def split_path: (Path, String) =

   127     elems match {

   128       case Path.Basic(s) :: xs => (new Path(xs), s)

   129       case _ => error("Cannot split path into dir/base: " + toString)

   130     }

   132   def dir: Path = split_path._1

   133   def base: Path = new Path(List(Path.Basic(split_path._2)))

   135   def ext(e: String): Path =

   136     if (e == "") this

   137     else {

   138       val (prfx, s) = split_path

   139       prfx + Path.basic(s + "." + e)

   140     }

   142   private val Ext = new Regex("(.*)\\.([^.]*)")

   144   def split_ext: (Path, String) =

   145   {

   146     val (prefix, base) = split_path

   147     base match {

   148       case Ext(b, e) => (prefix + Path.basic(b), e)

   149       case _ => (Path.basic(base), "")

   150     }

   151   }

   154   /* expand */

   156   def expand: Path =

   157   {

   158     def eval(elem: Path.Elem): List[Path.Elem] =

   159       elem match {

   160         case Path.Variable(s) =>

   161           Path.explode(Isabelle_System.getenv_strict(s)).elems

   162         case x => List(x)

   163       }

   165     new Path(Path.norm_elems(elems.map(eval).flatten))

   166   }

   169   /* platform file */

   171   def file: JFile = Isabelle_System.platform_file(this)

   172 }

author	wenzelm
	Fri, 20 Jul 2012 22:29:25 +0200
changeset 49424	0d2114eb412a
parent 49388	527e2bad7cca
child 49435	a8ed41b6280b
permissions	-rw-r--r--