/*
* Copyright (c) 2013 Patrick Scheibe
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package de.halirutan.mathematica.parsing.prattparser.parselets;
import com.intellij.lang.PsiBuilder;
import de.halirutan.mathematica.parsing.ParserBundle;
import de.halirutan.mathematica.parsing.prattparser.CriticalParserError;
import de.halirutan.mathematica.parsing.prattparser.MathematicaParser;
import static de.halirutan.mathematica.parsing.MathematicaElementTypes.SPAN;
import static de.halirutan.mathematica.parsing.MathematicaElementTypes.SPAN_EXPRESSION;
import static de.halirutan.mathematica.parsing.prattparser.ParseletProvider.getPrefixParselet;
/**
* Parses <code>Span</code> constructs. This parselet handles not situations like <code>list[[;;]]</code> or
* <code>list[[;;i]]</code> because this is a prefix operator and not infix.
*
* @author patrick (3/27/13)
*/
public class SpanParselet implements InfixParselet {
private final int myPrecedence;
public SpanParselet(int precedence) {
this.myPrecedence = precedence;
}
// Parses things like expr1;;expr2, expr0;; ;;expr1 or expr0;;expr1;;expr2.
@Override
public MathematicaParser.Result parse(MathematicaParser parser, MathematicaParser.Result left) throws CriticalParserError {
PsiBuilder.Marker spanMark = left.getMark().precede();
boolean skipped = false;
if (parser.matchesToken(SPAN)) {
parser.advanceLexer();
} else {
spanMark.drop();
throw new CriticalParserError(ParserBundle.message("Critical.span"));
}
// if we meet a second ;; right after the first ;; we just skip it
if (parser.matchesToken(SPAN)) {
skipped = true;
parser.advanceLexer();
}
// since here we met either expr0;; or expr0;;;;. By testing whether the next token is start of a new expression
// (which requires to start with a prefix operator) we can tell whether we met the form list[[expr0;;]] or
// which is a syntax error list[expr0;;;;]].
PrefixParselet nextPrefix = getPrefixParselet(parser.getTokenType());
if (nextPrefix == null) {
if (skipped) {
spanMark.error(ParserBundle.message("General.expr.expected.after", "'expr0;; ;;'"));
} else {
spanMark.done(SPAN_EXPRESSION);
}
return MathematicaParser.result(spanMark, SPAN_EXPRESSION, left.isParsed() && !skipped);
}
MathematicaParser.Result expr1 = parser.parseExpression(myPrecedence);
// if we had expr0;;;;expr1
if (skipped) {
spanMark.done(SPAN_EXPRESSION);
return MathematicaParser.result(spanMark, SPAN_EXPRESSION, left.isParsed() && expr1.isParsed());
}
if (parser.matchesToken(SPAN)) {
parser.advanceLexer();
MathematicaParser.Result expr2 = parser.parseExpression(myPrecedence);
if (expr2.isParsed()) {
spanMark.done(SPAN_EXPRESSION);
} else
spanMark.error(ParserBundle.message("General.expr.expected.after", "'expr0;;expr1;;'"));
return MathematicaParser.result(spanMark, SPAN_EXPRESSION, left.isParsed() && expr1.isParsed() && expr2.isParsed());
} else {
// we have the form expr0;;expr1
spanMark.done(SPAN_EXPRESSION);
return MathematicaParser.result(spanMark, SPAN_EXPRESSION, left.isParsed() && expr1.isParsed());
}
}
@Override
public int getMyPrecedence() {
return myPrecedence;
}
}