1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Copyright 2001-2004 The Apache Software Foundation.
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *     http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20 /*
  21  * $Id: UnaryOpExpr.java,v 1.2.4.1 2005/09/05 09:21:00 pvedula Exp $
  22  */
  23 
  24 package com.sun.org.apache.xalan.internal.xsltc.compiler;
  25 
  26 import com.sun.org.apache.bcel.internal.generic.InstructionList;
  27 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
  28 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
  29 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodType;
  30 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
  31 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
  32 
  33 /**
  34  * @author Jacek Ambroziak
  35  * @author Santiago Pericas-Geertsen
  36  */
  37 final class UnaryOpExpr extends Expression {
  38     private Expression _left;
  39 
  40     public UnaryOpExpr(Expression left) {
  41         (_left = left).setParent(this);
  42     }
  43 
  44     /**
  45      * Returns true if this expressions contains a call to position(). This is
  46      * needed for context changes in node steps containing multiple predicates.
  47      */
  48     public boolean hasPositionCall() {
  49         return(_left.hasPositionCall());
  50     }
  51 
  52     /**
  53      * Returns true if this expressions contains a call to last()
  54      */
  55     public boolean hasLastCall() {
  56             return(_left.hasLastCall());
  57     }
  58 
  59     public void setParser(Parser parser) {
  60         super.setParser(parser);
  61         _left.setParser(parser);
  62     }
  63 
  64     public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  65         final Type tleft = _left.typeCheck(stable);
  66         final MethodType ptype = lookupPrimop(stable, "u-",
  67                                               new MethodType(Type.Void,
  68                                                              tleft));
  69 
  70         if (ptype != null) {
  71             final Type arg1 = (Type) ptype.argsType().elementAt(0);
  72             if (!arg1.identicalTo(tleft)) {
  73                 _left = new CastExpr(_left, arg1);
  74             }
  75             return _type = ptype.resultType();
  76         }
  77 
  78         throw new TypeCheckError(this);
  79     }
  80 
  81     public String toString() {
  82         return "u-" + '(' + _left + ')';
  83     }
  84 
  85     public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  86         InstructionList il = methodGen.getInstructionList();
  87         _left.translate(classGen, methodGen);
  88         il.append(_type.NEG());
  89     }
  90 }