||= is much needed?

[T.J. Crowder]

On 14 June 2012 22:38, John Tamplin <jat at google.com> wrote:

> On Thu, Jun 14, 2012 at 5:32 PM, T.J. Crowder <tj at crowdersoftware.com>wrote:
>
>>
>>> Is ||= really worth it? It would not assign if the left side is truthy,
>>> but perhaps no one will mind.
>>>
>>
>> Nice-to-have. The fact it doesn't assign if the left side is truthy is
>> the only reason for having it, surely?
>>
>
> Plus not even evaluating the RHS if the LHS is truthy -- useful if the
> default is an expensive calculation.
>

Right, but `a = a || b` doesn't evaluate `b` if `a` is truthy, either. What I
meant was, if we have `a ??= b`, and of course we already have `a = a ||
b`, the only reason for having `a ||= b` is that it doesn't assign if `a`
is truthy.

-- T.J.
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