From: Einar Boson <einarmagnus@...>
Date: 2009-01-27T11:11:55+09:00
Subject: Conventions in ruby and the principle of least surprise

Hi guys, and hi Matz. I have a few questions about ruby syntax and
library that so far has had me surprised. I know Matz doesn't say that
ruby shouldn't surprise me, but rather not surprise him but still, i
would like to hear the reasoning behind a few weird things:

do..end vs. {}

Say I have this function:

def save_block name, &b
    @blocks ||= {}
    @blocks[name] = b
end

Now this is fine:

  save_block :say_hello do
    puts "hello!"
  end

but not this:

  save_block :say_hello {
    puts "hello!"
  }

I find that rather annoying but I guess it's to be able to write things
like

save_block ["name1_long", "name2_long", "short"].find {|n| n.size <=
5}.to_sym do
  puts "hello!"
end

Personally I would rather have had to use parentheses to bind the block
to find, but I realize that it's hardly up to me :)

Anyways. More serious, in my oppinion, is the fact that Array#insert and
String#insert are destructive without having an exclamation mark. Why is
that? I really do not expect them to change their owner.

>> hi = "hello world"
=> "hello world"
>> puts hi
hello world
=> nil
>> puts hi.insert(6, "surprising ")
hello surprising world
=> nil
>> puts hi
hello surprising world
=> nil

seriously, wtf? Why not `insert` and `insert!` that behave as expected?
Before I realized this I had a hard time tracking down some unexpected
behaviour.
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