ShowTreeVisitor.java

import absyn.*;


public class ShowTreeVisitor implements absyn.AbsynVisitor {

  private static final int SPACES = 4;

  private java.io.PrintStream out;

  public ShowTreeVisitor(java.io.PrintStream out) {
    this.out = out;
  }

  public ShowTreeVisitor() {
    this.out = System.out;
  }


  private void indent(int level) {
    for(int i = 0; i < level * SPACES; ++i) {
      out.print(' ');
    }
  }

  private void indent(int level, String message) {
    indent(level);
    out.println(message);
  }

  @Override
  public void visit(ArrayDec dec, int level, boolean isAddr) {
    indent(level, "ArrayDec: " + dec);
  }

  @Override
  public void visit(FunctionDec dec, int level, boolean isAddr) {
    indent(level, "FunctionDec: " + dec);
    indent(++level, "(params):");
    dec.getParams().accept(this, level, isAddr);

    Exp body = dec.getBody();
    if (!(body instanceof NilExp)) {
      indent(level, "(body):");
      body.accept(this, level, isAddr);
    }
  }

  @Override
  public void visit(SimpleDec dec, int level, boolean isAddr) {
    indent(level, "SimpleDec: " + dec);
  }

  @Override
  public void visit(AssignExp exp, int level, boolean isAddr) {
    indent(level, "AssignExp:");
    indent(++level, "(left):");
    exp.getLeft().accept(this, level, isAddr);
    indent(level, "(=right):");
    exp.getRight().accept(this, level, isAddr);
  }

  @Override
  public void visit(BoolExp exp, int level, boolean isAddr) {
    indent(level, "BoolExp: " + exp.getValue());
  }

  @Override
  public void visit(CallExp exp, int level, boolean isAddr) {
    indent(level, "CallExp: " + exp);
    List<?> args = exp.getArgs();
    args.accept(this, level + 1, isAddr);
  }

  @Override
  public void visit(CompoundExp exp, int level, boolean isAddr) {
    indent(level, "CompoundExp " + exp + ":");
    exp.getDecs().accept(this, ++level, isAddr);
    exp.getExps().accept(this, level, isAddr);
  }

  @Override
  public void visit(IfExp exp, int level, boolean isAddr) {
    indent(level, "IfExp:");

    indent(++level, "(condition):");
    exp.getCondition().accept(this, level, isAddr);

    indent(level, "(then):");
    exp.getThen().accept(this, level, isAddr);

    Exp elseBlock = exp.getElseBlock();

    if (!(elseBlock instanceof NilExp)) {
      indent(level, "(else):");
      elseBlock.accept(this, level, isAddr);
    }
  }

  @Override
  public void visit(WhileExp exp, int level, boolean isAddr) {
    indent(level, "WhileExp:");

    indent(++level, "(condition):");
    exp.getCondition().accept(this, level, isAddr);
    
    indent(level, "(body):");
    exp.getBody().accept(this, level, isAddr);
  }

  @Override
  public void visit(IntExp exp, int level, boolean isAddr) {
    indent(level, "IntExp: " + exp.getValue());
  }

  @Override
  public void visit(OpExp exp, int level, boolean isAddr) {
    indent(level, "OpExp (" + OpExp.opToString(exp.getOp()) + "):");
    exp.getLeft().accept(this, ++level, isAddr);
    exp.getRight().accept(this, level, isAddr);
  }

  @Override
  public void visit(VarExp exp, int level, boolean isAddr) {
    indent(level, "VarExp:");
    exp.getVariable().accept(this, ++level, isAddr);
  }

  @Override
  public void visit(ReturnExp exp, int level, boolean isAddr) {
    indent(level, "ReturnExp:");
    exp.getValue().accept(this, ++level, isAddr);
  }

  @Override
  public void visit(NilExp exp, int level, boolean isAddr) {
    // Do nothing
  }

  @Override
  public void visit(SynError err, int level, boolean isAddr) {
    indent(level, "Syntax Error " + err.getMessage());
  }

  @Override
  public void visit(SimpleVar var, int level, boolean isAddr) {
    indent(level, "SimpleVar: " + var);
  }

  @Override
  public void visit(IndexVar var, int level, boolean isAddr) {
    indent(level, "IndexVar: " + var);
    indent(++level, "(index):");
    var.getIndex().accept(this, level, isAddr);
  }

  @Override
  public void visit(NameType type, int level, boolean isAddr) {
    // Do nothing
  }

  @Override
  public <T extends Absyn> void visit(List<T> list, int level, boolean isAddr) {
    if (list == null) {
      return;
    }

    T head = list.getHead();

    if (head != null) {
      head.accept(this, level, isAddr);
    }

    List<T> tail = list.getTail();
    if (tail != null) {
      tail.accept(this, level, isAddr);
    }
  }

}