/* 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 -- with total quasi-ordering */
object Range
{
def apply(start: Offset): Range = Range(start, start)
}
sealed case class Range(val start: Offset, val stop: Offset)
{
// denotation: {start} Un {i. start < i & i < stop}
if (start > stop)
error("Bad range: [" + start.toString + ":" + stop.toString + "]")
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 -(i: Offset): Range = map(_ - i)
def is_singularity: Boolean = start == 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 restrict(that: Range): Range =
Range(this.start max that.start, this.stop min that.stop)
def try_restrict(that: Range): Option[Range] =
try { Some (restrict(that)) }
catch { case ERROR(_) => None }
}
/* information associated with text range */
case class Info[A](val range: Text.Range, val info: A)
{
def restrict(r: Text.Range): Info[A] = Info(range.restrict(r), info)
def try_restrict(r: Text.Range): Option[Info[A]] =
try { Some(Info(range.restrict(r), info)) }
catch { case ERROR(_) => None }
}
/* 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 (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)
def convert(range: Range): Range = range.map(convert)
def revert(range: Range): Range = range.map(revert)
/* 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))
}
}
}