Question

I never thought I’d have a need for anything this (since macros are bad, right?), but it turns out I do.

I find myself repeating the following pattern over and over again in my code, dozens if not hundreds of times:

object Function() {
    this.Blah = this.Blah.Resolve(...);
    if(this.Blah == null)
        return null;
    if(this.Blah.SomeFlag)
        return this.OtherFunction();

    // otherwise, continue processing...
}

I’d like to write something like this instead:

object Function() {
    this.Blah = this.Blah.Resolve(...);
    VerifyResolve(this.Blah);

    // continue processing...
}

Except the fact that the pattern contains conditional returns means I can’t factor out a function. I’ve had to subtly change the pattern once already, and since I couldn’t do a simple search it was a pain to find all the instances.

How can I avoid repeating myself needlessly, and make any future changes to this pattern easier?

Answer 1

You could say something like:

object Function()
{ 
    this.Blah = this.Blah.Resolve(...);
    object rc;
    if (!VerifyResolve(out rc)
       return rc;

    // continue processing... 
} 

bool VerifyResolve(out object rc)
{
    if(this.Blah == null)      
    {
        rc = null;
        return true;
    }
    if(this.Blah.SomeFlag)      
    {
        rc = this.OtherFunction();
        return true;
    }
    rc = null;
    return false;
}