Break out of a begin/end block early

I want a way to exit a begin/end block while still assigning the variable that its result is assigned to.

def foo  @foo ||= begin    puts "running"    return "leaving early" if true # would be some sort of calculation    # Other calculations  endend

What I hope to happen

> foorunning=> leaving early> foo=> leaving early

What actually happens

> foorunning=> leaving early> foorunning=> leaving early

The code doesn't work because return exits the entire method without setting @foo. Using break or next only work in loops. Does anything work within a begin block the way I'm thinking?

Current ways I can do it but was hoping to avoid:

• Assigning the variable within the begin block and returning
• Putting the remaining portion of the begin block in an if statement
• Performing the calculation before the begin block

There seem to be a lot of related questions about breaking out of blocks but I couldn't find one that answers this specific version (maybe because it's not possible).