Re: Object-relational impedence

Marshall <marshall.spight_at_gmail.com> wrote in news:a8e31977-9f84-4c58-bca3-e0aa4e855676_at_s19g2000prg.googlegroups.com:

> On Mar 10, 5:30 am, "Yagotta B. Kidding" <y..._at_mymail.com> wrote:
>> Marshall <marshall.spi..._at_gmail.com> wrote
>> > On Mar 9, 7:25 pm, "Yagotta B. Kidding" <y..._at_mymail.com> wrote:
>>
>> >> Superficially, you can perform the translation, but the
>> >> assignment required to imitate the projection makes any such
>> >> language not referentially transparent. You may consider the
>> >> non-transparency a non- issue of course.
>>
>> > Um, how so? I'm not sure I see what you mean.
>>
>> "A language that supports the concept that ``equals can be
>> substituted for equals'' in an expresssion without changing the value
>> of the expression is said to be referentially transparent.
>> Referential transparency is violated when we include set! in our
>> computer language. This makes it tricky to determine when we can
>> simplify expressions by substituting equivalent expressions.
>> Consequently, reasoning about programs that use assignment becomes
>> drastically more difficult."
>
> Dude? I'm a language junkie with an interest in FP. It wasn't the
> term "referential transparency" I was having trouble with. :-)
>
> Rather, I don't see where the assignment comes in.

You don't ?

>And
> Mr. Perryman's example was written in a single-assignment,
> mathematical style.

And yet you still do not see where the assignment comes in in Mr. Perryman's example. Received on Mon Mar 10 2008 - 19:47:06 CET