wenzelm@38425: /*  Title:      Pure/PIDE/text.scala
wenzelm@34276:     Author:     Fabian Immler, TU Munich
wenzelm@34276:     Author:     Makarius
wenzelm@34276: 
wenzelm@38425: Basic operations on plain text.
wenzelm@34276: */
wenzelm@34276: 
wenzelm@34276: package isabelle
wenzelm@34276: 
wenzelm@34276: 
wenzelm@44379: import scala.collection.mutable
wenzelm@44379: import scala.math.Ordering
wenzelm@44379: import scala.util.Sorting
wenzelm@44379: 
wenzelm@44379: 
wenzelm@38425: object Text
wenzelm@34276: {
wenzelm@38477:   /* offset */
wenzelm@38426: 
wenzelm@38426:   type Offset = Int
wenzelm@38426: 
wenzelm@38477: 
wenzelm@38565:   /* range -- with total quasi-ordering */
wenzelm@38477: 
wenzelm@38568:   object Range
wenzelm@38568:   {
wenzelm@38568:     def apply(start: Offset): Range = Range(start, start)
wenzelm@44379: 
wenzelm@44379:     object Ordering extends scala.math.Ordering[Text.Range]
wenzelm@44379:     {
wenzelm@44379:       def compare(r1: Text.Range, r2: Text.Range): Int = r1 compare r2
wenzelm@44379:     }
wenzelm@38568:   }
wenzelm@38568: 
wenzelm@38426:   sealed case class Range(val start: Offset, val stop: Offset)
wenzelm@38427:   {
wenzelm@38565:     // denotation: {start} Un {i. start < i & i < stop}
wenzelm@43425:     if (start > stop)
wenzelm@43425:       error("Bad range: [" + start.toString + ":" + stop.toString + "]")
wenzelm@38477: 
wenzelm@38563:     override def toString = "[" + start.toString + ":" + stop.toString + "]"
wenzelm@38563: 
wenzelm@38427:     def map(f: Offset => Offset): Range = Range(f(start), f(stop))
wenzelm@38427:     def +(i: Offset): Range = map(_ + i)
wenzelm@38570:     def -(i: Offset): Range = map(_ - i)
wenzelm@38662: 
wenzelm@38725:     def is_singularity: Boolean = start == stop
wenzelm@38662: 
wenzelm@38565:     def contains(i: Offset): Boolean = start == i || start < i && i < stop
wenzelm@38565:     def contains(that: Range): Boolean = this.contains(that.start) && that.stop <= this.stop
wenzelm@38565:     def overlaps(that: Range): Boolean = this.contains(that.start) || that.contains(this.start)
wenzelm@38565:     def compare(that: Range): Int = if (overlaps(that)) 0 else this.start compare that.start
wenzelm@38485: 
wenzelm@45240:     def apart(that: Range): Boolean =
wenzelm@45240:       (this.start max that.start) > (this.stop min that.stop)
wenzelm@45240: 
wenzelm@38564:     def restrict(that: Range): Range =
wenzelm@38485:       Range(this.start max that.start, this.stop min that.stop)
wenzelm@43428: 
wenzelm@43428:     def try_restrict(that: Range): Option[Range] =
wenzelm@45240:       if (this apart that) None
wenzelm@45240:       else Some(restrict(that))
wenzelm@45240: 
wenzelm@45240:     def try_join(that: Range): Option[Range] =
wenzelm@45240:       if (this apart that) None
wenzelm@45240:       else Some(Range(this.start min that.start, this.stop max that.stop))
wenzelm@38427:   }
wenzelm@38426: 
wenzelm@38426: 
wenzelm@44379:   /* perspective */
wenzelm@44379: 
wenzelm@44473:   object Perspective
wenzelm@44379:   {
wenzelm@44474:     val empty: Perspective = Perspective(Nil)
wenzelm@44379: 
wenzelm@44473:     def apply(ranges: Seq[Range]): Perspective =
wenzelm@44379:     {
wenzelm@44473:       val result = new mutable.ListBuffer[Text.Range]
wenzelm@44473:       var last: Option[Text.Range] = None
wenzelm@45240:       def ship(next: Option[Range]) { result ++= last; last = next }
wenzelm@45240: 
wenzelm@45240:       for (range <- ranges.sortBy(_.start))
wenzelm@44473:       {
wenzelm@44473:         last match {
wenzelm@45240:           case None => ship(Some(range))
wenzelm@45240:           case Some(last_range) =>
wenzelm@45240:             last_range.try_join(range) match {
wenzelm@45240:               case None => ship(Some(range))
wenzelm@45240:               case joined => last = joined
wenzelm@45240:             }
wenzelm@44473:         }
wenzelm@44379:       }
wenzelm@45240:       ship(None)
wenzelm@44473:       new Perspective(result.toList)
wenzelm@44379:     }
wenzelm@44473:   }
wenzelm@44473: 
wenzelm@45240:   class Perspective private(val ranges: List[Range]) // visible text partitioning in canonical order
wenzelm@44473:   {
wenzelm@44473:     def is_empty: Boolean = ranges.isEmpty
wenzelm@44473:     def range: Range =
wenzelm@44473:       if (is_empty) Range(0)
wenzelm@44473:       else Range(ranges.head.start, ranges.last.stop)
wenzelm@45631: 
wenzelm@45631:     override def hashCode: Int = ranges.hashCode
wenzelm@45631:     override def equals(that: Any): Boolean =
wenzelm@45631:       that match {
wenzelm@45631:         case other: Perspective => ranges == other.ranges
wenzelm@45631:         case _ => false
wenzelm@45631:       }
wenzelm@45240:     override def toString = ranges.toString
wenzelm@44379:   }
wenzelm@44379: 
wenzelm@44379: 
wenzelm@38577:   /* information associated with text range */
wenzelm@38577: 
wenzelm@43714:   sealed case class Info[A](val range: Text.Range, val info: A)
wenzelm@38577:   {
wenzelm@38577:     def restrict(r: Text.Range): Info[A] = Info(range.restrict(r), info)
wenzelm@43428:     def try_restrict(r: Text.Range): Option[Info[A]] =
wenzelm@43428:       try { Some(Info(range.restrict(r), info)) }
wenzelm@43650:       catch { case ERROR(_) => None }
wenzelm@38577:   }
wenzelm@38577: 
wenzelm@45470:   type Markup = Info[XML.Elem]
wenzelm@45455: 
wenzelm@38577: 
wenzelm@38426:   /* editing */
wenzelm@34286: 
wenzelm@38425:   object Edit
wenzelm@38425:   {
wenzelm@38426:     def insert(start: Offset, text: String): Edit = new Edit(true, start, text)
wenzelm@38426:     def remove(start: Offset, text: String): Edit = new Edit(false, start, text)
wenzelm@38425:   }
wenzelm@34286: 
wenzelm@45250:   class Edit private(val is_insert: Boolean, val start: Offset, val text: String)
wenzelm@38425:   {
wenzelm@38425:     override def toString =
wenzelm@38425:       (if (is_insert) "Insert(" else "Remove(") + (start, text).toString + ")"
wenzelm@34286: 
wenzelm@34286: 
wenzelm@38425:     /* transform offsets */
wenzelm@34286: 
wenzelm@38426:     private def transform(do_insert: Boolean, i: Offset): Offset =
wenzelm@38426:       if (i < start) i
wenzelm@43425:       else if (do_insert) i + text.length
wenzelm@38426:       else (i - text.length) max start
wenzelm@34286: 
wenzelm@43425:     def convert(i: Offset): Offset = transform(is_insert, i)
wenzelm@43425:     def revert(i: Offset): Offset = transform(!is_insert, i)
wenzelm@43425:     def convert(range: Range): Range = range.map(convert)
wenzelm@43425:     def revert(range: Range): Range = range.map(revert)
wenzelm@38425: 
wenzelm@34286: 
wenzelm@38425:     /* edit strings */
wenzelm@38425: 
wenzelm@38426:     private def insert(i: Offset, string: String): String =
wenzelm@38426:       string.substring(0, i) + text + string.substring(i)
wenzelm@34276: 
wenzelm@38426:     private def remove(i: Offset, count: Int, string: String): String =
wenzelm@38426:       string.substring(0, i) + string.substring(i + count)
wenzelm@38425: 
wenzelm@38425:     def can_edit(string: String, shift: Int): Boolean =
wenzelm@38425:       shift <= start && start < shift + string.length
wenzelm@38425: 
wenzelm@38425:     def edit(string: String, shift: Int): (Option[Edit], String) =
wenzelm@38425:       if (!can_edit(string, shift)) (Some(this), string)
wenzelm@38425:       else if (is_insert) (None, insert(start - shift, string))
wenzelm@38425:       else {
wenzelm@38426:         val i = start - shift
wenzelm@38426:         val count = text.length min (string.length - i)
wenzelm@38425:         val rest =
wenzelm@38425:           if (count == text.length) None
wenzelm@38425:           else Some(Edit.remove(start, text.substring(count)))
wenzelm@38426:         (rest, remove(i, count, string))
wenzelm@38425:       }
wenzelm@38425:   }
wenzelm@34276: }