/* Title: Pure/General/pretty.scala
Author: Makarius
Generic pretty printing module.
*/
package isabelle
object Pretty
{
/* XML constructors */
val space: XML.Body = List(XML.Text(Symbol.space))
def spaces(n: Int): XML.Body =
if (n == 0) Nil
else if (n == 1) space
else List(XML.Text(Symbol.spaces(n)))
def block(consistent: Boolean, indent: Int, body: XML.Body): XML.Tree =
XML.Elem(Markup.Block(consistent, indent), body)
def block(indent: Int, body: XML.Body): XML.Tree = block(false, indent, body)
def block(body: XML.Body): XML.Tree = block(2, body)
def brk(width: Int, indent: Int = 0): XML.Tree =
XML.Elem(Markup.Break(width, indent), spaces(width))
val fbrk: XML.Tree = XML.Text("\n")
def fbreaks(ts: List[XML.Tree]): XML.Body = Library.separate(fbrk, ts)
val Separator: XML.Body = List(XML.elem(Markup.SEPARATOR, space), fbrk)
def separate(ts: List[XML.Tree]): XML.Body = Library.separate(Separator, ts.map(List(_))).flatten
/* text metric -- standardized to width of space */
abstract class Metric
{
val unit: Double
def apply(s: String): Double
}
object Metric_Default extends Metric
{
val unit = 1.0
def apply(s: String): Double = s.length.toDouble
}
/* markup trees with physical blocks and breaks */
private def force_nat(i: Int): Int = i max 0
private sealed abstract class Tree { def length: Double }
private case class Block(
markup: Option[(Markup, Option[XML.Body])],
consistent: Boolean, indent: Int, body: List[Tree], length: Double) extends Tree
private case class Break(force: Boolean, width: Int, indent: Int) extends Tree
{ def length: Double = width.toDouble }
private case class Str(string: String, length: Double) extends Tree
private val FBreak = Break(true, 1, 0)
private def make_block(
markup: Option[(Markup, Option[XML.Body])],
consistent: Boolean,
indent: Int,
body: List[Tree]): Tree =
{
val indent1 = force_nat(indent)
def body_length(prts: List[Tree], len: Double): Double =
{
val (line, rest) =
Library.take_prefix[Tree]({ case Break(true, _, _) => false case _ => true }, prts)
val len1 = ((0.0 /: line) { case (l, t) => l + t.length }) max len
rest match {
case Break(true, _, ind) :: rest1 =>
body_length(Break(false, indent1 + ind, 0) :: rest1, len1)
case Nil => len1
}
}
Block(markup, consistent, indent1, body, body_length(body, 0.0))
}
/* formatted output */
private sealed case class Text(tx: XML.Body = Nil, pos: Double = 0.0, nl: Int = 0)
{
def newline: Text = copy(tx = fbrk :: tx, pos = 0.0, nl = nl + 1)
def string(s: String, len: Double): Text =
copy(tx = if (s == "") tx else XML.Text(s) :: tx, pos = pos + len)
def blanks(wd: Int): Text = string(Symbol.spaces(wd), wd.toDouble)
def content: XML.Body = tx.reverse
}
private def break_dist(trees: List[Tree], after: Double): Double =
trees match {
case (_: Break) :: _ => 0.0
case t :: ts => t.length + break_dist(ts, after)
case Nil => after
}
private def force_break(tree: Tree): Tree =
tree match { case Break(false, wd, ind) => Break(true, wd, ind) case _ => tree }
private def force_all(trees: List[Tree]): List[Tree] = trees.map(force_break(_))
private def force_next(trees: List[Tree]): List[Tree] =
trees match {
case Nil => Nil
case (t: Break) :: ts => force_break(t) :: ts
case t :: ts => t :: force_next(ts)
}
private val margin_default = 76.0
def formatted(input: XML.Body, margin: Double = margin_default,
metric: Metric = Metric_Default): XML.Body =
{
val breakgain = margin / 20
val emergencypos = (margin / 2).round.toInt
def make_tree(inp: XML.Body): List[Tree] =
inp flatMap {
case XML.Wrapped_Elem(markup, body1, body2) =>
List(make_block(Some(markup, Some(body1)), false, 0, make_tree(body2)))
case XML.Elem(markup, body) =>
markup match {
case Markup.Block(consistent, indent) =>
List(make_block(None, consistent, indent, make_tree(body)))
case Markup.Break(width, indent) =>
List(Break(false, force_nat(width), force_nat(indent)))
case Markup(Markup.ITEM, _) =>
List(make_block(None, false, 2,
make_tree(XML.elem(Markup.BULLET, space) :: space ::: body)))
case _ =>
List(make_block(Some((markup, None)), false, 0, make_tree(body)))
}
case XML.Text(text) =>
Library.separate(FBreak, split_lines(text).map(s => Str(s, metric(s))))
}
def format(trees: List[Tree], blockin: Int, after: Double, text: Text): Text =
trees match {
case Nil => text
case Block(markup, consistent, indent, body, blen) :: ts =>
val pos1 = (text.pos + indent).ceil.toInt
val pos2 = pos1 % emergencypos
val blockin1 = if (pos1 < emergencypos) pos1 else pos2
val d = break_dist(ts, after)
val body1 = if (consistent && text.pos + blen > margin - d) force_all(body) else body
val btext =
markup match {
case None => format(body1, blockin1, d, text)
case Some((m, markup_body)) =>
val btext0 = format(body1, blockin1, d, text.copy(tx = Nil))
val elem =
markup_body match {
case None => XML.Elem(m, btext0.content)
case Some(b) => XML.Wrapped_Elem(m, b, btext0.content)
}
btext0.copy(tx = elem :: text.tx)
}
val ts1 = if (text.nl < btext.nl) force_next(ts) else ts
format(ts1, blockin, after, btext)
case Break(force, wd, ind) :: ts =>
if (!force &&
text.pos + wd <= ((margin - break_dist(ts, after)) max (blockin + breakgain)))
format(ts, blockin, after, text.blanks(wd))
else format(ts, blockin, after, text.newline.blanks(blockin + ind))
case Str(s, len) :: ts => format(ts, blockin, after, text.string(s, len))
}
format(make_tree(input), 0, 0.0, Text()).content
}
def string_of(input: XML.Body, margin: Double = margin_default,
metric: Metric = Metric_Default): String =
XML.content(formatted(input, margin, metric))
}