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Comment by pjmlp | Hacker News Reader

Have a look at Smalltalk blocks, or FP languages, to see where Ruby's inspiration comes from.

Ruby is basically what happens when Smalltalk and Perl (compare the command line and the "$"-variables for example) has a baby and it inexplicably looks much better than both parents.

An interesting thing about Smalltalk and Ruby blocks is that they aren't just anonymous functions/lambdas, right? i.e. if you 'return' / '^' in a block, it's the context around the block that you return from, not just the block itself? That's what struck me about both of them when I was used to thinking in basic Lisp terms.

As much as I love Ruby (and I love it a lot - I right now have Claude fix eigenclass compilation issues in another window in my long-languishing Ruby compiler hobby project), this is also the root of a lot of confusion.

Ruby has two types of closures: lambda's, where return returns to the caller, and proc's/blocks where return acts as a return in the defining scope.

Beginners often struggle with the distinction between lambda and block, and often will be wildly confused if they ever see "proc" in the wild.

Yet lambda and proc both return a Proc object, and if you take the value of a block, you also get a Proc object... Just with different return semantics...

It'd be nice if this was a bit clearer.

Yes, that is why that behaviour is known as closures.

Also why in languages like C++, you get to control what is captured from the calling context.

My next post, which is on loops, is about the common stuff with smalltalk as well!

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