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/*******************************************************************************
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/*******************************************************************************
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 * File: robot.y
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 * File: robot.y
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 *
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 *
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 * Copyright (c) 2006, Ira W. Snyder (devel@irasnyder.com)
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 * Copyright (c) 2006, Ira W. Snyder (devel@irasnyder.com)
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 * License: GNU General Public License v2
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 * License: GNU General Public License v2
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 *
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 *
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 * This file implements the grammar that controls our fictional apple-bag
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 * This file implements the grammar that controls our fictional apple-bag
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 * robot from Project #3, Question #2.
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 * robot from Project #3, Question #2.
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%}
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%}
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/* Token Declarations */
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/* Token Declarations */
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%token PUT
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%token PUT
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%token TAKE
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%token TAKE
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%token NL
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%token RESET
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/* Robot Grammar */
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/* Robot Grammar */
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%%
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%%
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program : program line
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    | ;
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line: NL        { if (interactive) System.out.print ("Line: "); }
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program : S         { System.out.println ("There are: " + r.getVal() + " apples in the bag!"); };
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    | S NL      { System.out.println ("There are: " + r.getVal() + " apples in the bag!");
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                  if (interactive) System.out.print ("Line: "); }
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    | RESET     { r.reset(); System.out.println ("Reset the robot"); };
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S : PUT S TAKE S    { System.out.println ("S -> PUT S TAKE S"); }
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S : PUT S TAKE S    { System.out.println ("S -> PUT S TAKE S"); }
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    | PUT S         { System.out.println ("S -> PUT S"); r.incVal(); }
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    | PUT S         { System.out.println ("S -> PUT S"); r.incVal(); }
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    |               { System.out.println ("S -> epsilon"); };
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    |               { System.out.println ("S -> epsilon"); };
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%%
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%%
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private Yylex lexer;
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private Yylex lexer;
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static boolean interactive = false;
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public void yyerror (String error)
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public void yyerror (String error)
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{
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{
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    System.out.println ("Parse Error: " + error);
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    System.out.println ("Parse Error: " + error);
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}
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}
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    lexer = new Yylex (r, this);
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    lexer = new Yylex (r, this);
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}
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}
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public static void main (String[] args) throws Exception
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public static void main (String[] args) throws Exception
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{
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{
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    Parser yyparser = null;
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    if (args.length > 0)
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    {
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        // read via file argument
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        yyparser = new Parser (new FileReader (args[0]));
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    }
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    else
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    {
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        // interactive mode
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        yyparser = new Parser (new InputStreamReader (System.in));
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        /*
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        System.out.println ("Specify the file to use as the first command-line");
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        System.out.println ("option. (EX: java Parser filename.txt)");
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        System.exit (1);
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        */
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        System.out.println("[Quit with CTRL-D]");
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        System.out.print("Expression: ");
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        interactive = true;
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    }
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    try
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    try
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    {
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    {
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        Parser yyparser = new Parser (new FileReader (args[0]));
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        yyparser.yyparse();
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        yyparser.yyparse();
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    }
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    }
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    catch (Exception e)
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    catch (Exception e)
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    {
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    {
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        System.out.println ("Tried to take too many apples out of the bag!");
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        System.out.println ("Tried to take too many apples out of the bag!");
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    }
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    }
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    if (interactive)
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    {
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        System.out.println();
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        System.out.println("Have a nice day");
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    }
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}
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}
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public class Robot
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public class Robot
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{
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{
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    int val = 0;
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    int val = 0;
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    void incVal () { val++; }
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    void incVal () { val++; }
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    void decVal () { val--; }
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    void decVal () { val--; }
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    int  getVal () { return val; }
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    int  getVal () { return val; }
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    void reset  () { val = 0; }
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}
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}
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Robot r = new Robot();
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Robot r = new Robot();
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