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/* Title: Pure/General/scan.scala
Author: Makarius
Efficient scanning of keywords and tokens.
*/
package isabelle
import scala.annotation.tailrec
import scala.collection.{IndexedSeq, Traversable, TraversableOnce}
import scala.util.matching.Regex
import scala.util.parsing.input.{OffsetPosition, Position => InputPosition,
Reader, CharSequenceReader, PagedSeq}
import scala.util.parsing.combinator.RegexParsers
import java.io.{File => JFile, BufferedInputStream, FileInputStream, InputStream}
import java.net.URL
object Scan
{
/** context of partial line-oriented scans **/
abstract class Line_Context
case object Finished extends Line_Context
case class Quoted(quote: String) extends Line_Context
case object Verbatim extends Line_Context
case class Cartouche(depth: Int) extends Line_Context
case class Comment_Prefix(symbol: Symbol.Symbol) extends Line_Context
case class Cartouche_Comment(depth: Int) extends Line_Context
case class Comment(depth: Int) extends Line_Context
/** parser combinators **/
object Parsers extends Parsers
trait Parsers extends RegexParsers
{
override val whiteSpace: Regex = "".r
/* optional termination */
def opt_term[T](p: => Parser[T]): Parser[Option[T]] =
p ^^ (x => Some(x)) | """\z""".r ^^ (_ => None)
/* repeated symbols */
def repeated(pred: Symbol.Symbol => Boolean, min_count: Int, max_count: Int): Parser[String] =
new Parser[String]
{
def apply(in: Input) =
{
val start = in.offset
val end = in.source.length
val matcher = new Symbol.Matcher(in.source)
var i = start
var count = 0
var finished = false
while (!finished && i < end && count < max_count) {
val n = matcher(i, end)
val sym = in.source.subSequence(i, i + n).toString
if (pred(sym)) { i += n; count += 1 }
else finished = true
}
if (count < min_count) Failure("bad input", in)
else Success(in.source.subSequence(start, i).toString, in.drop(i - start))
}
}.named("repeated")
def one(pred: Symbol.Symbol => Boolean): Parser[String] =
repeated(pred, 1, 1)
def maybe(pred: Symbol.Symbol => Boolean): Parser[String] =
repeated(pred, 0, 1)
def many(pred: Symbol.Symbol => Boolean): Parser[String] =
repeated(pred, 0, Integer.MAX_VALUE)
def many1(pred: Symbol.Symbol => Boolean): Parser[String] =
repeated(pred, 1, Integer.MAX_VALUE)
/* character */
def character(pred: Char => Boolean): Symbol.Symbol => Boolean =
(s: Symbol. Symbol) => s.length == 1 && pred(s.charAt(0))
/* quoted strings */
private def quoted_body(quote: Symbol.Symbol): Parser[String] =
{
rep(many1(sym => sym != quote && sym != "\\") | "\\" + quote | "\\\\" |
("""\\\d\d\d""".r ^? { case x if x.substring(1, 4).toInt <= 255 => x })) ^^ (_.mkString)
}
def quoted(quote: Symbol.Symbol): Parser[String] =
{
quote ~ quoted_body(quote) ~ quote ^^ { case x ~ y ~ z => x + y + z }
}.named("quoted")
def quoted_content(quote: Symbol.Symbol, source: String): String =
{
require(parseAll(quoted(quote), source).successful, "no quoted text")
val body = source.substring(1, source.length - 1)
if (body.exists(_ == '\\')) {
val content =
rep(many1(sym => sym != quote && sym != "\\") |
"\\" ~> (quote | "\\" | """\d\d\d""".r ^^ { case x => x.toInt.toChar.toString }))
parseAll(content ^^ (_.mkString), body).get
}
else body
}
def quoted_line(quote: Symbol.Symbol, ctxt: Line_Context): Parser[(String, Line_Context)] =
{
ctxt match {
case Finished =>
quote ~ quoted_body(quote) ~ opt_term(quote) ^^
{ case x ~ y ~ Some(z) => (x + y + z, Finished)
case x ~ y ~ None => (x + y, Quoted(quote)) }
case Quoted(q) if q == quote =>
quoted_body(quote) ~ opt_term(quote) ^^
{ case x ~ Some(y) => (x + y, Finished)
case x ~ None => (x, ctxt) }
case _ => failure("")
}
}.named("quoted_line")
def recover_quoted(quote: Symbol.Symbol): Parser[String] =
quote ~ quoted_body(quote) ^^ { case x ~ y => x + y }
/* verbatim text */
private def verbatim_body: Parser[String] =
rep(many1(sym => sym != "*") | """\*(?!\})""".r) ^^ (_.mkString)
def verbatim: Parser[String] =
{
"{*" ~ verbatim_body ~ "*}" ^^ { case x ~ y ~ z => x + y + z }
}.named("verbatim")
def verbatim_content(source: String): String =
{
require(parseAll(verbatim, source).successful, "no verbatim text")
source.substring(2, source.length - 2)
}
def verbatim_line(ctxt: Line_Context): Parser[(String, Line_Context)] =
{
ctxt match {
case Finished =>
"{*" ~ verbatim_body ~ opt_term("*}") ^^
{ case x ~ y ~ Some(z) => (x + y + z, Finished)
case x ~ y ~ None => (x + y, Verbatim) }
case Verbatim =>
verbatim_body ~ opt_term("*}") ^^
{ case x ~ Some(y) => (x + y, Finished)
case x ~ None => (x, Verbatim) }
case _ => failure("")
}
}.named("verbatim_line")
val recover_verbatim: Parser[String] =
"{*" ~ verbatim_body ^^ { case x ~ y => x + y }
/* nested text cartouches */
def cartouche_depth(depth: Int): Parser[(String, Int)] = new Parser[(String, Int)]
{
require(depth >= 0, "bad cartouche depth")
def apply(in: Input) =
{
val start = in.offset
val end = in.source.length
val matcher = new Symbol.Matcher(in.source)
var i = start
var d = depth
var finished = false
while (!finished && i < end) {
val n = matcher(i, end)
val sym = in.source.subSequence(i, i + n).toString
if (Symbol.is_open(sym)) { i += n; d += 1 }
else if (Symbol.is_close(sym) && d > 0) { i += n; d -= 1; if (d == 0) finished = true }
else if (d > 0) i += n
else finished = true
}
if (i == start) Failure("bad input", in)
else Success((in.source.subSequence(start, i).toString, d), in.drop(i - start))
}
}.named("cartouche_depth")
def cartouche: Parser[String] =
cartouche_depth(0) ^? { case (x, d) if d == 0 => x }
def cartouche_line(ctxt: Line_Context): Parser[(String, Line_Context)] =
{
def cartouche_context(d: Int): Line_Context =
if (d == 0) Finished else Cartouche(d)
ctxt match {
case Finished =>
cartouche_depth(0) ^^ { case (c, d) => (c, cartouche_context(d)) }
case Cartouche(depth) =>
cartouche_depth(depth) ^^ { case (c, d) => (c, cartouche_context(d)) }
case _ => failure("")
}
}
val recover_cartouche: Parser[String] =
cartouche_depth(0) ^^ (_._1)
def cartouche_content(source: String): String =
{
def err(): Nothing = error("Malformed text cartouche: " + quote(source))
val source1 =
Library.try_unprefix(Symbol.open_decoded, source) orElse
Library.try_unprefix(Symbol.open, source) getOrElse err()
Library.try_unsuffix(Symbol.close_decoded, source1) orElse
Library.try_unsuffix(Symbol.close, source1) getOrElse err()
}
/* nested comments */
private def comment_depth(depth: Int): Parser[(String, Int)] = new Parser[(String, Int)]
{
require(depth >= 0, "bad comment depth")
val comment_text: Parser[List[String]] =
rep1(many1(sym => sym != "*" && sym != "(") | """\*(?!\))|\((?!\*)""".r)
def apply(in: Input) =
{
var rest = in
def try_parse[A](p: Parser[A]): Boolean =
{
parse(p ^^^ (()), rest) match {
case Success(_, next) => { rest = next; true }
case _ => false
}
}
var d = depth
var finished = false
while (!finished) {
if (try_parse("(*")) d += 1
else if (d > 0 && try_parse("*)")) { d -= 1; if (d == 0) finished = true }
else if (d == 0 || !try_parse(comment_text)) finished = true
}
if (in.offset < rest.offset)
Success((in.source.subSequence(in.offset, rest.offset).toString, d), rest)
else Failure("comment expected", in)
}
}.named("comment_depth")
def comment: Parser[String] =
comment_depth(0) ^? { case (x, d) if d == 0 => x }
def comment_line(ctxt: Line_Context): Parser[(String, Line_Context)] =
{
val depth =
ctxt match {
case Finished => 0
case Comment(d) => d
case _ => -1
}
if (depth >= 0)
comment_depth(depth) ^^
{ case (x, 0) => (x, Finished)
case (x, d) => (x, Comment(d)) }
else failure("")
}
val recover_comment: Parser[String] =
comment_depth(0) ^^ (_._1)
def comment_content(source: String): String =
{
require(parseAll(comment, source).successful, "no comment")
source.substring(2, source.length - 2)
}
/* keyword */
def literal(lexicon: Lexicon): Parser[String] = new Parser[String]
{
def apply(in: Input) =
{
val result = lexicon.scan(in)
if (result.isEmpty) Failure("keyword expected", in)
else Success(result, in.drop(result.length))
}
}.named("keyword")
}
/** Lexicon -- position tree **/
object Lexicon
{
/* representation */
private sealed case class Tree(branches: Map[Char, (String, Tree)])
private val empty_tree = Tree(Map())
val empty: Lexicon = new Lexicon(empty_tree)
def apply(elems: String*): Lexicon = empty ++ elems
}
final class Lexicon private(rep: Lexicon.Tree)
{
/* auxiliary operations */
private def dest(tree: Lexicon.Tree, result: List[String]): List[String] =
(result /: tree.branches.toList) ((res, entry) =>
entry match { case (_, (s, tr)) =>
if (s.isEmpty) dest(tr, res) else dest(tr, s :: res) })
private def lookup(str: CharSequence): Option[(Boolean, Lexicon.Tree)] =
{
val len = str.length
@tailrec def look(tree: Lexicon.Tree, tip: Boolean, i: Int): Option[(Boolean, Lexicon.Tree)] =
{
if (i < len) {
tree.branches.get(str.charAt(i)) match {
case Some((s, tr)) => look(tr, s.nonEmpty, i + 1)
case None => None
}
}
else Some(tip, tree)
}
look(rep, false, 0)
}
def completions(str: CharSequence): List[String] =
lookup(str) match {
case Some((true, tree)) => dest(tree, List(str.toString))
case Some((false, tree)) => dest(tree, Nil)
case None => Nil
}
/* pseudo Set methods */
def raw_iterator: Iterator[String] = dest(rep, Nil).iterator
def iterator: Iterator[String] = dest(rep, Nil).sorted.iterator
override def toString: String = iterator.mkString("Lexicon(", ", ", ")")
def is_empty: Boolean = rep.branches.isEmpty
def contains(elem: String): Boolean =
lookup(elem) match {
case Some((tip, _)) => tip
case _ => false
}
/* build lexicon */
def + (elem: String): Lexicon =
if (contains(elem)) this
else {
val len = elem.length
def extend(tree: Lexicon.Tree, i: Int): Lexicon.Tree =
if (i < len) {
val c = elem.charAt(i)
val end = (i + 1 == len)
tree.branches.get(c) match {
case Some((s, tr)) =>
Lexicon.Tree(tree.branches +
(c -> (if (end) elem else s, extend(tr, i + 1))))
case None =>
Lexicon.Tree(tree.branches +
(c -> (if (end) elem else "", extend(Lexicon.empty_tree, i + 1))))
}
}
else tree
new Lexicon(extend(rep, 0))
}
def ++ (elems: TraversableOnce[String]): Lexicon = (this /: elems)(_ + _)
def ++ (other: Lexicon): Lexicon =
if (this eq other) this
else if (is_empty) other
else this ++ other.raw_iterator
def -- (remove: Traversable[String]): Lexicon =
if (remove.exists(contains))
Lexicon.empty ++ iterator.filterNot(a => remove.exists(b => a == b))
else this
/* scan */
def scan(in: Reader[Char]): String =
{
val source = in.source
val offset = in.offset
val len = source.length - offset
@tailrec def scan_tree(tree: Lexicon.Tree, result: String, i: Int): String =
{
if (i < len) {
tree.branches.get(source.charAt(offset + i)) match {
case Some((s, tr)) => scan_tree(tr, if (s.isEmpty) result else s, i + 1)
case None => result
}
}
else result
}
scan_tree(rep, "", 0)
}
}
/** read stream without decoding: efficient length operation **/
private class Restricted_Seq(seq: IndexedSeq[Char], start: Int, end: Int)
extends CharSequence
{
def charAt(i: Int): Char =
if (0 <= i && i < length) seq(start + i)
else throw new IndexOutOfBoundsException
def length: Int = end - start // avoid expensive seq.length
def subSequence(i: Int, j: Int): CharSequence =
if (0 <= i && i <= j && j <= length) new Restricted_Seq(seq, start + i, start + j)
else throw new IndexOutOfBoundsException
override def toString: String =
{
val buf = new StringBuilder(length)
for (offset <- start until end) buf.append(seq(offset))
buf.toString
}
}
abstract class Byte_Reader extends Reader[Char] with AutoCloseable
private def make_byte_reader(stream: InputStream, stream_length: Int): Byte_Reader =
{
val buffered_stream = new BufferedInputStream(stream)
val seq = new PagedSeq(
(buf: Array[Char], offset: Int, length: Int) =>
{
var i = 0
var c = 0
var eof = false
while (!eof && i < length) {
c = buffered_stream.read
if (c == -1) eof = true
else { buf(offset + i) = c.toChar; i += 1 }
}
if (i > 0) i else -1
})
val restricted_seq = new Restricted_Seq(seq, 0, stream_length)
class Paged_Reader(override val offset: Int) extends Byte_Reader
{
override lazy val source: CharSequence = restricted_seq
def first: Char = if (seq.isDefinedAt(offset)) seq(offset) else '\u001a'
def rest: Paged_Reader = if (seq.isDefinedAt(offset)) new Paged_Reader(offset + 1) else this
def pos: InputPosition = new OffsetPosition(source, offset)
def atEnd: Boolean = !seq.isDefinedAt(offset)
override def drop(n: Int): Paged_Reader = new Paged_Reader(offset + n)
def close { buffered_stream.close }
}
new Paged_Reader(0)
}
def byte_reader(file: JFile): Byte_Reader =
make_byte_reader(new FileInputStream(file), file.length.toInt)
def byte_reader(url: URL): Byte_Reader =
{
val connection = url.openConnection
val stream = connection.getInputStream
val stream_length = connection.getContentLength
make_byte_reader(stream, stream_length)
}
def reader_is_utf8(reader: Reader[Char]): Boolean =
reader.isInstanceOf[Byte_Reader]
def reader_decode_utf8(is_utf8: Boolean, s: String): String =
if (is_utf8) UTF8.decode_permissive(s) else s
def reader_decode_utf8(reader: Reader[Char], s: String): String =
reader_decode_utf8(reader_is_utf8(reader), s)
/* plain text reader */
def char_reader(text: CharSequence): CharSequenceReader =
new CharSequenceReader(text)
}
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