author | wenzelm |
Fri, 16 Jan 2009 22:54:11 +0100 | |
changeset 29521 | 736bf7117153 |
parent 29180 | 62513d4d34c2 |
child 29563 | 4773c5c994dc |
permissions | -rw-r--r-- |
27930 | 1 |
/* Title: Pure/General/yxml.scala |
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Author: Makarius |
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Efficient text representation of XML trees. |
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*/ |
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package isabelle |
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import java.util.regex.Pattern |
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object YXML { |
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/* chunk markers */ |
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private val X = '\5' |
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private val Y = '\6' |
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private val X_string = X.toString |
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private val Y_string = Y.toString |
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def detect(source: CharSequence) = { |
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source.length >= 2 && |
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source.charAt(0) == X && |
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source.charAt(1) == Y |
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} |
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replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
27930
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/* iterate over chunks (resembles space_explode in ML) */ |
f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
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f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
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private def chunks(sep: Char, source: CharSequence) = new Iterator[CharSequence] { |
f34ff5e7728f
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private val end = source.length |
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private var state = if (end == 0) None else get_chunk(-1) |
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private def get_chunk(i: Int) = { |
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if (i < end) { |
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var j = i; do j += 1 while (j < end && source.charAt(j) != sep) |
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Some((source.subSequence(i + 1, j), j)) |
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} |
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replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
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else None |
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} |
f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
27930
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wenzelm
parents:
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def hasNext() = state.isDefined |
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def next() = state match { |
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case Some((s, i)) => { state = get_chunk(i); s } |
f34ff5e7728f
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case None => throw new NoSuchElementException("next on empty iterator") |
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} |
f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
27930
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} |
f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
27930
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wenzelm
parents:
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/* parsing */ |
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private def err(msg: String) = error("Malformed YXML: " + msg) |
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private def err_attribute() = err("bad attribute") |
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private def err_element() = err("bad element") |
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private def err_unbalanced(name: String) = |
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if (name == "") err("unbalanced element") |
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else err("unbalanced element \"" + name + "\"") |
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parse_attrib: more efficient due to indexOf('=');
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private def parse_attrib(source: CharSequence) = { |
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parse_attrib: more efficient due to indexOf('=');
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val s = source.toString |
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val i = s.indexOf('=') |
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if (i <= 0) err_attribute() |
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(s.substring(0, i), s.substring(i + 1)) |
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} |
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def parse_body(source: CharSequence) = { |
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/* stack operations */ |
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var stack: List[((String, XML.Attributes), List[XML.Tree])] = null |
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def add(x: XML.Tree) = (stack: @unchecked) match { |
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case ((elem, body) :: pending) => stack = (elem, x :: body) :: pending |
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} |
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def push(name: String, atts: XML.Attributes) = |
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if (name == "") err_element() |
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else stack = ((name, atts), Nil) :: stack |
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def pop() = (stack: @unchecked) match { |
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case ((("", _), _) :: _) => err_unbalanced("") |
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case (((name, atts), body) :: pending) => |
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stack = pending; add(XML.Elem(name, atts, body.reverse)) |
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} |
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/* parse chunks */ |
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stack = List((("", Nil), Nil)) |
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27943
f34ff5e7728f
replaced Pattern.split by chunks iterator (more efficient, resembles ML version more closely);
wenzelm
parents:
27930
diff
changeset
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for (chunk <- chunks(X, source) if chunk != "") { |
27945
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
diff
changeset
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if (chunk == Y_string) pop() |
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
diff
changeset
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else { |
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
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chunks(Y, chunk).toList match { |
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
diff
changeset
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case "" :: name :: atts => push(name.toString, atts.map(parse_attrib)) |
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
diff
changeset
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case txts => for (txt <- txts) add(XML.Text(txt.toString)) |
d2dc5a1903e8
tuned parse performance: avoid splitting terminal Y chunk;
wenzelm
parents:
27944
diff
changeset
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} |
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} |
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} |
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stack match { |
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case List((("", _), result)) => result.reverse |
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case ((name, _), _) :: _ => err_unbalanced(name) |
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} |
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} |
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def parse(source: CharSequence) = |
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parse_body(source) match { |
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case List(result) => result |
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case Nil => XML.Text("") |
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case _ => err("multiple results") |
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} |
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/* failsafe parsing */ |
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private def markup_failsafe(source: CharSequence) = |
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XML.Elem (Markup.BAD, Nil, |
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List(XML.Text(source.toString.replace(X_string, "\\<^X>").replace(Y_string, "\\<^Y>")))) |
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def parse_body_failsafe(source: CharSequence) = { |
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try { parse_body(source) } |
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catch { case _: RuntimeException => List(markup_failsafe(source)) } |
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} |
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def parse_failsafe(source: CharSequence) = { |
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try { parse(source) } |
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catch { case _: RuntimeException => markup_failsafe(source) } |
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} |
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} |