simpleexpression.java

一种将c高级语言转化给VHDL的编译器

/*
 *
 LA-CC 05-135 Trident 0.7.1

Copyright Notice
Copyright 2006 (c) the Regents of the University of California.

This Software was produced under a U.S. Government contract
(W-7405-ENG-36) by Los Alamos National Laboratory, which is operated
by the University of California for the U.S. Department of Energy. The
U.S. Government is licensed to use, reproduce, and distribute this
Software. Permission is granted to the public to copy and use this
Software without charge, provided that this Notice and any statement
of authorship are reproduced on all copies. Neither the Government nor
the University makes any warranty, express or implied, or assumes any
liability or responsibility for the user of this Software.


*/

package fp.util.vhdl.generator;

import java.util.*;

public class SimpleExpression extends CheckObject implements VHDLout, Operation, Choice, Primary {

  String _sign = EMPTY;
 
  // Terms should be fancier -- but not right now...

  // Set the check arrays
  static final Class[]  _classes = { Term.class, Factor.class, Primary.class };
  static final String[] _ops = { PLUS, MINUS, CONCAT };


  SimpleExpression(Object left, String op, Object right) {
    super(_classes, _ops, left, op, right);
  }


  public SimpleExpression(String sign, Term term) {
    this(term, null, null);
    if (PLUS.equals(sign) || MINUS.equals(sign)) {
      _sign = sign;
    }
  }

  public SimpleExpression(Object o) {
    this(o, null, null);
  }


  class ExpTerm {
    // should this be an interface ??
    String add_operator;
    Object term;

    ExpTerm(String s, Object t) {
      add_operator = s;
      term = t;
    }
  }

  protected void addTerm(String op, Object term) { 
    if (objectAllowed(term) && operatorAllowed(op)) 
      _operands.add(new ExpTerm(op, term)); 
  }

  protected void addTerm(Object term) {
    if (objectAllowed(term)) 
      _operands.add(new ExpTerm(NOP, term));
  }

  public SimpleExpression add(Object term) { 
    addTerm(PLUS, term); 
    return this;
  }

  public SimpleExpression sub(Object term) { 
    addTerm(MINUS, term); 
    return this;
  }

  public SimpleExpression concat(Object term) { 
    addTerm(CONCAT, term);
    return this;
  }

  
  public StringBuffer toVHDL(StringBuffer s, String pre) {
    s.append(pre);
    s.append(_sign);
    for(ListIterator list_iter=_operands.listIterator(); list_iter.hasNext();) {
      ExpTerm term = (ExpTerm)list_iter.next();
      if (!EMPTY.equals(_sign)) 
	s.append(" ");
      if (!NOP.equals(term.add_operator)) {
	s.append(" ").append(term.add_operator).append(" ");
      }
      ((VHDLout)term.term).toVHDL(s, "");
    }
    return s;
  }

  public String toString() {
    return toVHDL(new StringBuffer(), "").toString();
  }


  public static void main(String args[]) {
    // mult div mod rem

    SimpleName a = new SimpleName("a");
    SimpleName a1 = new SimpleName("a_1");
    SimpleName b = new SimpleName("b");
    SimpleName c = new SimpleName("c");

    System.out.println("Primaries "+a+" "+b+" "+c+"\n");

    SimpleExpression se = new SimpleExpression(a, ADD, new Object());
    print(se);

    se = new SimpleExpression(a, ADD, new Paren(new Mult(a,b)));
    print(se);

    se = new SimpleExpression(new Paren(new Add(a,b)), SUB, c);
    print(se);

    se = new Sub(new Mult(a,b), new Paren(new Add(a,b,c)));
    print(se);

    //Term t3 = new Div(new Paren(new Mult(a,b)), 
    //new Paren(new Mult(c,a1)));

    
  }

  public static void print(SimpleExpression f) {
    System.out.println("SimpleExpression: "+f);
  }


  

}