/* Title: Pure/Thy/thy_syntax.scala
Author: Makarius
Superficial theory syntax: tokens and spans.
*/
package isabelle
import scala.collection.mutable
import scala.annotation.tailrec
object Thy_Syntax
{
/** parse spans **/
def parse_spans(toks: List[Token]): List[List[Token]] =
{
val result = new mutable.ListBuffer[List[Token]]
val span = new mutable.ListBuffer[Token]
val whitespace = new mutable.ListBuffer[Token]
def flush(buffer: mutable.ListBuffer[Token])
{
if (!buffer.isEmpty) { result += buffer.toList; buffer.clear }
}
for (tok <- toks) {
if (tok.is_command) { flush(span); flush(whitespace); span += tok }
else if (tok.is_ignored) whitespace += tok
else { span ++= whitespace; whitespace.clear; span += tok }
}
flush(span); flush(whitespace)
result.toList
}
/** text edits **/
def text_edits(session: Session, previous: Document.Version,
edits: List[Document.Node_Text_Edit]): (List[Document.Edit[Command]], Document.Version) =
{
/* phase 1: edit individual command source */
@tailrec def edit_text(eds: List[Text.Edit], commands: Linear_Set[Command])
: Linear_Set[Command] =
{
eds match {
case e :: es =>
Document.Node.command_starts(commands.iterator).find {
case (cmd, cmd_start) =>
e.can_edit(cmd.source, cmd_start) ||
e.is_insert && e.start == cmd_start + cmd.length
} match {
case Some((cmd, cmd_start)) if e.can_edit(cmd.source, cmd_start) =>
val (rest, text) = e.edit(cmd.source, cmd_start)
val new_commands = commands.insert_after(Some(cmd), Command.unparsed(text)) - cmd
edit_text(rest.toList ::: es, new_commands)
case Some((cmd, cmd_start)) =>
edit_text(es, commands.insert_after(Some(cmd), Command.unparsed(e.text)))
case None =>
require(e.is_insert && e.start == 0)
edit_text(es, commands.insert_after(None, Command.unparsed(e.text)))
}
case Nil => commands
}
}
/* phase 2: recover command spans */
@tailrec def recover_spans(commands: Linear_Set[Command]): Linear_Set[Command] =
{
commands.iterator.find(_.is_unparsed) match {
case Some(first_unparsed) =>
val first =
commands.reverse_iterator(first_unparsed).find(_.is_command) getOrElse commands.head
val last =
commands.iterator(first_unparsed).find(_.is_command) getOrElse commands.last
val range =
commands.iterator(first).takeWhile(_ != last).toList ::: List(last)
val sources = range.flatMap(_.span.map(_.source))
val spans0 = parse_spans(session.current_syntax().scan(sources.mkString))
val (before_edit, spans1) =
if (!spans0.isEmpty && first.is_command && first.span == spans0.head)
(Some(first), spans0.tail)
else (commands.prev(first), spans0)
val (after_edit, spans2) =
if (!spans1.isEmpty && last.is_command && last.span == spans1.last)
(Some(last), spans1.take(spans1.length - 1))
else (commands.next(last), spans1)
val inserted = spans2.map(span => new Command(session.new_id(), span))
val new_commands =
commands.delete_between(before_edit, after_edit).append_after(before_edit, inserted)
recover_spans(new_commands)
case None => commands
}
}
/* resulting document edits */
{
val doc_edits = new mutable.ListBuffer[Document.Edit[Command]]
var nodes = previous.nodes
for ((name, text_edits) <- edits) {
val commands0 = nodes(name).commands
val commands1 = edit_text(text_edits, commands0)
val commands2 = recover_spans(commands1) // FIXME somewhat slow
val removed_commands = commands0.iterator.filter(!commands2.contains(_)).toList
val inserted_commands = commands2.iterator.filter(!commands0.contains(_)).toList
val cmd_edits =
removed_commands.reverse.map(cmd => (commands0.prev(cmd), None)) :::
inserted_commands.map(cmd => (commands2.prev(cmd), Some(cmd)))
doc_edits += (name -> Some(cmd_edits))
nodes += (name -> new Document.Node(commands2))
}
(doc_edits.toList, new Document.Version(session.new_id(), nodes))
}
}
}