Re: Boolean operators without commutators vs. ALL/ANY

On Mon, Jun 13, 2011 at 3:01 AM, Florian Pflug <fgp(at)phlo(dot)org> wrote:
> On Jun13, 2011, at 05:12 , Robert Haas wrote:
>> On Sun, Jun 12, 2011 at 7:46 AM, Florian Pflug <fgp(at)phlo(dot)org> wrote:
>>> So I the end, I had to wrap the sub-query in a SQL-language
>>> function and use that in the check constraint. While this
>>> solved my immediate problem, the necessity of doing that
>>> highlights a few problems
>>>
>>> (A) "~" is an extremely bad name for the regexp-matching
>>> operators, since it's visual form is symmetric but it's
>>> behaviour isn't. This doesn't only make its usage very
>>> error-prone, it also makes it very hard to come up with
>>> sensible name for an commutator of "~". I suggest that we
>>> add "=~" as an alias for "~", "~=" as an commutator
>>> for "=~", and deprecate "~". The same holds for "~~".
>>
>> Does any other database or programming language implement it this way?
>
> Ruby has "=~", which returns the position of the regexp's first
> match, or nil if there is none.
>
> $ ruby -e "puts 'hello' =~ /l+/"
> 2
> $ ruby -e "puts 'hello' =~ /x+/"
> nil

Sure. Some languages use =~ and some use just ~... I was just
wondering if anyone thought the commutator of =~ was ~=...

--
Robert Haas
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