/* Copyright (c) 2006, Sun Microsystems, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the Sun Microsystems, Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */ options { USER_TOKEN_MANAGER = true; } PARSER_BEGIN(CalcInputParser) public class CalcInputParser { } PARSER_END(CalcInputParser) void Input() : { double larg = 0.0; double rarg; } { ( [ larg=Number() { CalcGUI.print(larg); } ] ( <ADD> rarg=Number() { larg = larg + rarg; CalcGUI.print(larg); } | <SUB> rarg=Number() { larg = larg - rarg; CalcGUI.print(larg); } | <MUL> rarg=Number() { larg = larg * rarg; CalcGUI.print(larg); } | <DIV> rarg=Number() { larg = (rarg==0) ? Float.POSITIVE_INFINITY : (larg / rarg); CalcGUI.print(larg); } )* <EQ: "=" > )* } double Number() : { Token t; String image = ""; double value = 0.0; double decimalPlace = 1.0; } { ( t=<DIGIT> { image += t.image; value = value*10 + Integer.parseInt(t.image); CalcGUI.print(image); } )+ [ <DOT> { image += "."; CalcGUI.print(image); } ( t=<DIGIT> { image += t.image; decimalPlace *= 0.1; value = value + Integer.parseInt(t.image)*decimalPlace; CalcGUI.print(image); } )+ ] { return value; } | <DOT> { image = "0."; CalcGUI.print(image); } ( t=<DIGIT> { image += t.image; decimalPlace *= 0.1; value = value + Integer.parseInt(t.image)*decimalPlace; CalcGUI.print(image); } )+ { return value; } }