Jskad/source/org/thdl/tib/text/ttt/ParseIterator.java
dchandler 7198f23361 I really hesitate to commit this because I'm not sure what it brings to the
table exactly and I fear that it makes the ACIP->Tibetan converter code
a lot uglier.  The TODO(DLC)[EWTS->Tibetan] comments littered throughout
are part of the ugliness; they point to the ugliness.  If each were addressed,
cleanliness could perhaps be achieved.

I've largely forgotten exactly what this change does, but it attempts to
improve EWTS->Tibetan conversion.  The lexer is probably really, really
primitive.  I concentrate here on converting a single tsheg bar rather than
a whole document.

Eclipse was used during part of my journey here and some imports were
reorganized merely because I could.  :)

(Eclipse was needed when the usual ant build failed to run a new test
EWTSTest.  And I wanted its debugger.)

Next steps: end-to-end EWTS tests should bring many problems to light.  Fix
those.  Triage all the TODO comments.

I don't know that I'll ever really trust the implementation.  The tests are
valuable, though.  A clean implementation of EWTS->Tibetan in Jython
might hold enough interest for me; I'd like to learn Python.
2005-06-20 06:18:00 +00:00

100 lines
3.3 KiB
Java

/*
The contents of this file are subject to the THDL Open Community License
Version 1.0 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License on the THDL web site
(http://www.thdl.org/).
Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
License for the specific terms governing rights and limitations under the
License.
The Initial Developer of this software is the Tibetan and Himalayan Digital
Library (THDL). Portions created by the THDL are Copyright 2003 THDL.
All Rights Reserved.
Contributor(s): ______________________________________.
*/
package org.thdl.tib.text.ttt;
import java.util.ArrayList;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/** An object that can iterate over an {@link TParseTree}.
*
* @author David Chandler */
class ParseIterator {
private ArrayList al = null;
private int sz;
private ListIterator[] iterators;
private boolean first = true;
private boolean hasNextParse = true;
/** Constructs a new ParseIterator that iterates over a list of
* TStackListLists. */
ParseIterator(ArrayList al) {
this.al = al;
sz = al.size();
iterators = new ListIterator[sz];
hasNextParse = false;
for (int i = 0; i < sz; i++) {
iterators[i] = ((TStackListList)al.get(i)).listIterator();
if (iterators[i].hasNext())
hasNextParse = true;
}
}
/** Returns true if and only if there is another parse
* available. */
boolean hasNext() {
return hasNextParse;
}
/** Returns the next available parse. */
TStackList next() {
if (!hasNextParse)
throw new NoSuchElementException("no parses left");
if (first) {
first = false;
TStackList x = new TStackList();
for (int i = 0; i < sz; i++) {
TStackList nextSL = (TStackList)iterators[i].next();
x.addAll(nextSL);
}
// The next guy is found by taking the previous item of
// each iterator.
hasNextParse = false;
for (int i = sz - 1; i >= 0; i--) {
if (iterators[i].hasNext()) {
iterators[i].next();
hasNextParse = true;
break;
}
}
return x;
}
// Up the rightmost iterator you can. If you can, reset all
// guys to the right of it. If you can't, we're done.
TStackList x = new TStackList(sz);
hasNextParse = false;
for (int i = sz - 1; i >= 0; i--) {
TStackList prevSL = (TStackList)iterators[i].previous();
x.addAll(0, prevSL);
iterators[i].next();
if (!hasNextParse && iterators[i].hasNext()) {
hasNextParse = true;
iterators[i].next();
// Reset all iterators to the right of i.
for (int j = i + 1; j < sz; j++) {
while (iterators[j].hasPrevious())
iterators[j].previous();
iterators[j].next();
}
}
}
return x;
}
}