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Comment by carbon8 | Hacker News Reader

"it has four goddamn callable types [Methods, Procs, Blocks, Lambdas] that all turn into one another at different points, but you still can't pass around non-anonymous callables directly!"

Aside from the errors in this sentence (blocks, procs and lambdas are all just Proc objects, and you can pass around methods using method(:method_name)), assuming that passing around methods is supposedly common really betrays a python-centric point of view.

In Ruby, passing around methods by name is very uncommon. Running ack through 407 gems I see 116 instances of it, period. That's 116 times in some huge number of lines of ruby code that someone typed method(:some_method).

It's clear why this wouldn't be a common thing in Ruby: all of the Proc types are flexible enough that it's rarely necessary to pass around methods. I find it incredibly hard to believe that people who complain about this are actually encountering this while using Ruby as Ruby.

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"Aside from the errors in this sentence (blocks, procs and lambdas are all just Proc objects"

No, they're different: http://innig.net/software/ruby/closures-in-ruby.rb

They are indeed all Proc objects:

    Proc.new {}.class
    => Proc
    lambda {}.class
    => Proc
    proc {}.class
    => Proc
    def block_class(&block) block.class end
    block_class {}
    => Proc

That write-up does have some great info in it, though.

Edit: there's an interesting comment on wycats' post that suggests the &block creates a Proc, and that blocks themselves are neither objects nor callable, ie, they can only be used directly with yield. That makes sense.

Even in that case, the original point still stands; we're still only dealing with Methods and Procs.

My link empirically demonstrates that all 7(!) constructs behave differently, regardless of what foo.class says. I personally have been burned by the differences between them, so I'll continue to support people differentiating between them, even if the interpret lies.

"My link empirically demonstrates that all 7(!) constructs behave differently"

It explicitly doesn't. Read it again. Immediately after listing his 7 constructs he points out that a number of them are actually the same thing, and in the summary he clearly explains that there are only 4 different behaviors. His 7 constructs (which include methods and bare blocks) are actually only 3 or, arguably, 3.5/4 (his numbers in parens):

blocks, which aren't callable without being wrapped in a Proc in CRuby (1, 2)

Procs (two types: Proc.new/&block and lambda) (3, 4, 5, 6)

methods (7)

There two types of Procs, plain procs and lambda, with lambda's differences being how it checks arguments and its return behavior, as I noted yesterday in another comment in this discussion (http://news.ycombinator.com/item?id=1141030).

So, again, the original comment, "four goddamn callable types [Methods, Procs, Blocks, Lambdas]," neglects the fact that #call on the last three is actually just Proc#call.

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