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/* Title: Pure/PIDE/text.scala
Author: Fabian Immler, TU Munich
Author: Makarius
Basic operations on plain text.
*/
package isabelle
import scala.collection.mutable
import scala.util.Sorting
object Text
{
/* offset */
type Offset = Int
/* range -- with total quasi-ordering */
object Range
{
def apply(start: Offset): Range = Range(start, start)
val full: Range = apply(0, Integer.MAX_VALUE / 2)
val offside: Range = apply(-1)
object Ordering extends scala.math.Ordering[Range]
{
def compare(r1: Range, r2: Range): Int = r1 compare r2
}
}
sealed case class Range(start: Offset, stop: Offset)
{
// denotation: {start} Un {i. start < i & i < stop}
if (start > stop)
error("Bad range: [" + start.toString + ".." + stop.toString + "]")
override def toString: String = "[" + start.toString + ".." + stop.toString + "]"
def length: Offset = stop - start
def map(f: Offset => Offset): Range = Range(f(start), f(stop))
def +(i: Offset): Range = if (i == 0) this else map(_ + i)
def -(i: Offset): Range = if (i == 0) this else map(_ - i)
def is_singularity: Boolean = start == stop
def inflate_singularity: Range = if (is_singularity) Range(start, start + 1) else this
def touches(i: Offset): Boolean = start <= i && i <= stop
def contains(i: Offset): Boolean = start == i || start < i && i < stop
def contains(that: Range): Boolean = this.contains(that.start) && that.stop <= this.stop
def overlaps(that: Range): Boolean = this.contains(that.start) || that.contains(this.start)
def compare(that: Range): Int = if (overlaps(that)) 0 else this.start compare that.start
def apart(that: Range): Boolean =
(this.start max that.start) > (this.stop min that.stop)
def restrict(that: Range): Range =
Range(this.start max that.start, this.stop min that.stop)
def try_restrict(that: Range): Option[Range] =
if (this apart that) None
else Some(restrict(that))
def try_join(that: Range): Option[Range] =
if (this apart that) None
else Some(Range(this.start min that.start, this.stop max that.stop))
def substring(text: String): String = text.substring(start, stop)
def try_substring(text: String): Option[String] =
try { Some(substring(text)) }
catch { case _: IndexOutOfBoundsException => None }
}
/* perspective */
object Perspective
{
val empty: Perspective = Perspective(Nil)
def full: Perspective = Perspective(List(Range.full))
def apply(ranges: List[Range]): Perspective =
{
val result = new mutable.ListBuffer[Range]
var last: Option[Range] = None
def ship(next: Option[Range]) { result ++= last; last = next }
for (range <- ranges.sortBy(_.start))
{
last match {
case None => ship(Some(range))
case Some(last_range) =>
last_range.try_join(range) match {
case None => ship(Some(range))
case joined => last = joined
}
}
}
ship(None)
new Perspective(result.toList)
}
}
final class Perspective private(
val ranges: List[Range]) // visible text partitioning in canonical order
{
def is_empty: Boolean = ranges.isEmpty
def range: Range =
if (is_empty) Range(0)
else Range(ranges.head.start, ranges.last.stop)
override def hashCode: Int = ranges.hashCode
override def equals(that: Any): Boolean =
that match {
case other: Perspective => ranges == other.ranges
case _ => false
}
override def toString: String = ranges.toString
}
/* information associated with text range */
sealed case class Info[A](range: Range, info: A)
{
def restrict(r: Range): Info[A] = Info(range.restrict(r), info)
def try_restrict(r: Range): Option[Info[A]] = range.try_restrict(r).map(Info(_, info))
def map[B](f: A => B): Info[B] = Info(range, f(info))
}
type Markup = Info[XML.Elem]
/* editing */
object Edit
{
def insert(start: Offset, text: String): Edit = new Edit(true, start, text)
def remove(start: Offset, text: String): Edit = new Edit(false, start, text)
def inserts(start: Offset, text: String): List[Edit] =
if (text == "") Nil else List(insert(start, text))
def removes(start: Offset, text: String): List[Edit] =
if (text == "") Nil else List(remove(start, text))
def replace(start: Offset, old_text: String, new_text: String): List[Edit] =
if (old_text == new_text) Nil
else removes(start, old_text) ::: inserts(start, new_text)
}
final class Edit private(val is_insert: Boolean, val start: Offset, val text: String)
{
override def toString: String =
(if (is_insert) "Insert(" else "Remove(") + (start, text).toString + ")"
/* transform offsets */
private def transform(do_insert: Boolean, i: Offset): Offset =
if (i < start) i
else if (do_insert) i + text.length
else (i - text.length) max start
def convert(i: Offset): Offset = transform(is_insert, i)
def revert(i: Offset): Offset = transform(!is_insert, i)
/* edit strings */
private def insert(i: Offset, string: String): String =
string.substring(0, i) + text + string.substring(i)
private def remove(i: Offset, count: Offset, string: String): String =
string.substring(0, i) + string.substring(i + count)
def can_edit(string: String, shift: Offset): Boolean =
shift <= start && start < shift + string.length
def edit(string: String, shift: Offset): (Option[Edit], String) =
if (!can_edit(string, shift)) (Some(this), string)
else if (is_insert) (None, insert(start - shift, string))
else {
val i = start - shift
val count = text.length min (string.length - i)
val rest =
if (count == text.length) None
else Some(Edit.remove(start, text.substring(count)))
(rest, remove(i, count, string))
}
}
}
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