bundles/org.simantics.basicexpression/src/org/simantics/basicexpression/Expressions.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.basicexpression;
  13
  14 import java.io.PushbackReader;
  15 import java.io.StringReader;
  16
  17 import org.simantics.basicexpression.analysis.DepthFirstAdapter;
  18 import org.simantics.basicexpression.lexer.Lexer;
  19 import org.simantics.basicexpression.node.Start;
  20 import org.simantics.basicexpression.parser.Parser;
  21 import org.slf4j.Logger;
  22 import org.slf4j.LoggerFactory;
  23
  24 public class Expressions {
  25
  26         private static final Logger LOGGER = LoggerFactory.getLogger(Expressions.class);
  27
  28         private static final boolean DEBUG = false;
  29
  30     public static void evaluate(String expression, DepthFirstAdapter evaluator) {
  31
  32         try
  33         {
  34             // Create a Parser instance.
  35             Parser p =
  36                 new Parser(
  37                         new Lexer(
  38                                 new PushbackReader(new StringReader(expression))));
  39
  40             // Parse the input.
  41             Start tree = p.parse();
  42
  43             if(DEBUG)
  44                 tree.apply(new PrettyPrintExpressionVisitor());
  45
  46 //            System.out.println("tree=" + tree.getClass().getName());
  47
  48             // Apply the translation.
  49             tree.apply(evaluator);
  50
  51         }
  52         catch(Exception e)
  53         {
  54                 if (LOGGER.isDebugEnabled())
  55                         LOGGER.debug("Failed to evaluate expression {}", expression, e);
  56                 evaluator.except(e);
  57         }
  58
  59     }
  60
  61 }