/* Title: Pure/PIDE/text.scala
Author: Fabian Immler, TU Munich
Author: Makarius
Basic operations on plain text.
*/
package isabelle
object Text
{
/* offset */
type Offset = Int
/* range: interval with total quasi-ordering */
sealed case class Range(val start: Offset, val stop: Offset)
{
require(start <= stop)
override def toString = "[" + start.toString + ":" + stop.toString + "]"
def map(f: Offset => Offset): Range = Range(f(start), f(stop))
def +(i: Offset): Range = map(_ + i)
def contains(i: Offset): Boolean = start <= i && i < stop
def contains(that: Range): Boolean =
this == that || this.contains(that.start) && that.stop <= this.stop
def overlaps(that: Range): Boolean =
this == that || this.contains(that.start) || that.contains(this.start)
def compare(that: Range): Int =
if (overlaps(that)) 0
else if (this.start < that.start) -1
else 1
def start_range: Range = Range(start, start)
def stop_range: Range = Range(stop, stop)
def intersect(that: Range): Range =
Range(this.start max that.start, this.stop min that.stop)
}
/* 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)
}
class Edit(val is_insert: Boolean, val start: Offset, val text: String)
{
override def toString =
(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 (is_insert == do_insert) i + text.length
else (i - text.length) max start
def convert(i: Offset): Offset = transform(true, i)
def revert(i: Offset): Offset = transform(false, 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: Int, string: String): String =
string.substring(0, i) + string.substring(i + count)
def can_edit(string: String, shift: Int): Boolean =
shift <= start && start < shift + string.length
def edit(string: String, shift: Int): (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))
}
}
}