Avoiding abstract

[Frits van Bommel]

Oliver Ruebenkoenig wrote:
> Hi everyone,
> 
> the following code does what i want. I was wondering if the same out put can be produced without having the abstract char [] rawSymName(); in the Expr class? Thanks for any hints and thoughts,

It looks like rawSymName() does something very similar to 
Object.toString(). So given that, why not reuse that one? As an added 
bonus, your writefln() calls get shorter because it automatically calls 
toString() on Object parameters.
---
import std.stdio;

Expr mySymbol;

public class Expr {
public
     abstract Expr head();
}


class Symbol : public Expr {
public
     this( char [] name ) {
         this.itsName = name;
     }
     Expr head() { return mySymbol; }
     char [] toString () {
         return this.itsName;
     }
private
     char [] itsName;
}

int main( char [][] arg ) {

     Expr myString;

     mySymbol = new Symbol("Symbol");
     myString = new Symbol("String");

     writefln(mySymbol );
     writefln(mySymbol.head() );
     writefln(mySymbol.head().head() );

     writefln(myString.head().head() );

     return 0;
}
---

Of course, this isn't very helpful if you were already using toString 
for another representation of your objects...