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Hi --

On Wed, 5 Sep 2007, Peñá, Botp wrote:

> From: Robert Klemme [mailto:shortcutter / googlemail.com]
> # 2007/9/4, Yossef Mendelssohn <ymendel / pobox.com>:
> # > If '"x+=1" will always be "x=x+1"', what's the problem in
> # having x ||=
> # > 1 always be x = x || 1?
> # That an assignment of x=x is useless (basically a nop in the standard
> # case of x being a variable).
>
> consider,
>
> irb(main):074:0* h=Hash.new
> => {}
> irb(main):075:0> h[5] = h[5]
> => nil
> irb(main):076:0> h
> => {5=>nil}
> irb(main):062:0* h=Hash.new(1)
> => {}
> irb(main):063:0> h[5] = h[5]
> => 1
> irb(main):064:0> h
> => {5=>1}
>
> thus h[k] = h[k] could mean
>    h[k] = h.default   or
>    h[k] = nil
>
> definitely not useless and not noop.

It's really always h[k] = h.default -- it's just that the default
default, so to speak, is nil.


David

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