/*
* 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.psi.tree.IElementType;
import de.halirutan.mathematica.parsing.MathematicaElementTypes;
import de.halirutan.mathematica.parsing.ParserBundle;
import de.halirutan.mathematica.parsing.prattparser.CriticalParserError;
import de.halirutan.mathematica.parsing.prattparser.MathematicaParser;
/**
* Utility class for parsing.
*
* @author patrick (3/30/13)
*/
public final class ParserUtil {
private ParserUtil() {
}
/**
* Parses an expression sequence. These sequences are pretty common in function calls like f[a,b,c,d] or in lists
* {1,2,3,4} and are just a comma separated list of expressions which go as long as we don't find the right delimiter.
* Note that we do not accept {1,2,,,3} which would be valid Mathematica syntax but is not used in real applications.
* Therefore, we will give an error instead because the user most probably did a mistake.
*
* @param parser
* Parser which provides the token-stream, the builder, etc
* @param rightDel
* Token where we will stop the sequence parsing
* @return The parsing result which is true iff all sub-expressions were successfully parsed.
* @throws CriticalParserError
*/
static MathematicaParser.Result parseSequence(MathematicaParser parser, IElementType rightDel) throws CriticalParserError {
MathematicaParser.Result result = MathematicaParser.notParsed();
boolean sequenceParsed = true;
// The following is not correct regarding the syntax of the Mathematica language because f[a,,b] is equivalent to
// f[a, Null, b] but most people don't know this and just made an error when they typed
// a comma with no expression. Therefore we will only regard f[a,b,c,d,..] as correct function calls.
// Note, that it is always possible to write f[a, Null, b] explicitly, so we don't loose expression power.
while (true) {
while (parser.matchesToken(MathematicaElementTypes.COMMA)) {
parser.advanceLexer();
parser.error(ParserBundle.message("General.expr.expected.before.comma"));
sequenceParsed = false;
}
if (parser.matchesToken(rightDel)) {
break;
}
result = parser.parseExpression();
sequenceParsed &= result.isParsed();
// if we couldn't parseSequence the argument expression and the next token is neither a comma nor
// a closing brace/bracket, then we are lost at this point and should not try further to parseSequence something.
if (!result.isParsed() && !(parser.matchesToken(MathematicaElementTypes.COMMA) || parser.matchesToken(rightDel))) {
sequenceParsed = false;
break;
}
// Jump over a comma after an expression was parsed in e.g. f[expr1, expr2, ...]
// Note, when the comma is directly followed by the closing ] (or }) then we mark it with an error since
// something like f[expr1,expr2,] is not considered to be a bug.
if (parser.matchesToken(MathematicaElementTypes.COMMA)) {
if (parser.matchesToken(MathematicaElementTypes.COMMA, rightDel)) {
parser.error(ParserBundle.message("General.unexpected.character", ","));
parser.advanceLexer();
break;
}
parser.advanceLexer();
}
if (parser.matchesToken(rightDel)) {
break;
}
}
return MathematicaParser.result(result.getMark(), result.getToken(), sequenceParsed);
}
}