javacc-7.0.1.examples.SimpleExamples.NL_Xlator.jj Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of javacc Show documentation
Show all versions of javacc Show documentation
JavaCC is a parser/scanner generator for Java.
/* 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.
*/
PARSER_BEGIN(NL_Xlator)
/** New line translator. */
public class NL_Xlator {
/** Main entry point. */
public static void main(String args[]) throws ParseException {
NL_Xlator parser = new NL_Xlator(System.in);
parser.ExpressionList();
}
}
PARSER_END(NL_Xlator)
SKIP :
{
" "
| "\t"
| "\n"
| "\r"
}
TOKEN :
{
< ID: ["a"-"z","A"-"Z","_"] ( ["a"-"z","A"-"Z","_","0"-"9"] )* >
|
< NUM: ( ["0"-"9"] )+ >
}
/** Top level production. */
void ExpressionList() :
{
String s;
}
{
{
System.out.println("Please type in an expression followed by a \";\" or ^D to quit:");
System.out.println("");
}
( s=Expression() ";"
{
System.out.println(s);
System.out.println("");
System.out.println("Please type in another expression followed by a \";\" or ^D to quit:");
System.out.println("");
}
)*
}
/** An Expression. */
String Expression() :
{
java.util.Vector termimage = new java.util.Vector();
String s;
}
{
s=Term()
{
termimage.addElement(s);
}
( "+" s=Term()
{
termimage.addElement(s);
}
)*
{
if (termimage.size() == 1) {
return (String)termimage.elementAt(0);
} else {
s = "the sum of " + (String)termimage.elementAt(0);
for (int i = 1; i < termimage.size()-1; i++) {
s += ", " + (String)termimage.elementAt(i);
}
if (termimage.size() > 2) {
s += ",";
}
s += " and " + (String)termimage.elementAt(termimage.size()-1);
return s;
}
}
}
/** A Term. */
String Term() :
{
java.util.Vector factorimage = new java.util.Vector();
String s;
}
{
s=Factor()
{
factorimage.addElement(s);
}
( "*" s=Factor()
{
factorimage.addElement(s);
}
)*
{
if (factorimage.size() == 1) {
return (String)factorimage.elementAt(0);
} else {
s = "the product of " + (String)factorimage.elementAt(0);
for (int i = 1; i < factorimage.size()-1; i++) {
s += ", " + (String)factorimage.elementAt(i);
}
if (factorimage.size() > 2) {
s += ",";
}
s += " and " + (String)factorimage.elementAt(factorimage.size()-1);
return s;
}
}
}
/** A Factor. */
String Factor() :
{
Token t;
String s;
}
{
t=
{
return t.image;
}
|
t=
{
return t.image;
}
|
"(" s=Expression() ")"
{
return s;
}
}