/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2012:
* Stanislav Poslavsky <stvlpos@mail.ru>
* Bolotin Dmitriy <bolotin.dmitriy@gmail.com>
*
* This file is part of Redberry.
*
* Redberry is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Redberry is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Redberry. If not, see <http://www.gnu.org/licenses/>.
*/
package cc.redberry.core.parser;
import cc.redberry.core.indices.IndicesFactory;
import cc.redberry.core.indices.SimpleIndices;
import cc.redberry.core.utils.IntArrayList;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
public class ParserSimpleTensor implements NodeParser {
public static final ParserSimpleTensor INSTANCE = new ParserSimpleTensor();
private ParserSimpleTensor() {
}
@Override
public ParseNodeSimpleTensor parseNode(String expression, Parser parser) {
IntArrayList indicesList = new IntArrayList();
boolean indexMode = false;
int indexState = 0;
StringBuilder nameBuilder = new StringBuilder();
StringBuilder indicesString = null;
int level = 0;
for (char c : expression.toCharArray()) {
if (c == '{') {
level++;
continue;
}
if (c == '}') {
level--;
continue;
}
if (c == '^') {
assert level == 0;
if (indexMode)
ParserIndices.parseIndices(indicesList, indicesString, indexState);
indexMode = true;
indexState = 1;
indicesString = new StringBuilder();
continue;
}
if (c == '_' && level == 0) {
if (indexMode)
ParserIndices.parseIndices(indicesList, indicesString, indexState);
indexMode = true;
indexState = 0;
indicesString = new StringBuilder();
continue;
}
if (!indexMode)
nameBuilder.append(c);
else
indicesString.append(c);
}
if (level != 0)
throw new BracketsError();
if (indexMode)
ParserIndices.parseIndices(indicesList, indicesString, indexState);
SimpleIndices indices = IndicesFactory.createSimple(null, indicesList.toArray());
String name = nameBuilder.toString();
return new ParseNodeSimpleTensor(indices, name);
}
@Override
public int priority() {
return 0;
}
}