Re: DEC64=="Bee's knees"?

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From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.programming
Subject	Re: DEC64=="Bee's knees"?
Date	Tue, 13 Feb 2018 05:13:33 +0000
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luser droog <mijoryx@yahoo.com> writes:

> I was watching some youtube videos about language design
> and what the languages of the future should be like. And
> one video strongly suggested that 'int' be dropped as a
> basic type in new languages in favor of DEC64.
>
> DEC64 is a sort of hybrid floating-point/scaled-integer
> type. (https://en.wikipedia.org/wiki/DEC64) It has a 56 bit
> mantissa, and an 8 bit decimal exponent.

The wiki pages says "[i]ts aim is to sidestep the rounding errors common
to the widespread IEEE 754 format" but you can't really avoid rounding
errors.  You just get to choose which ones you have!

> Since the exponent is decimal, the type can easily represent
> 'normal' decimal numbers like .2 without the bizarre effects
> that binary fp's repeating expansion produces.

1/3 can not be represented, for example.  That might surprise some
people more than 0.2 not being representable in conventional binary FP.
It rather depends on the problem domain.

> What problems might be encountered by (users of) a new 
> language offering dec64 as its basic numeric type and 
> eschewing 'int'?

That depends on the problem domain too, but like JavaScript does, you'd
probably need to provide a set of integer-like operations (integer
division, mod, bit-wise operations) and so on because most programmers
would expect them.

Also worth noting is that there is already a relatively widely supported
IEEE decimal floating-point standard.  It would have to compete with
that.

-- 
Ben.

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DEC64=="Bee's knees"? luser droog <mijoryx@yahoo.com> - 2018-02-12 19:12 -0800
  Re: DEC64=="Bee's knees"? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-13 05:13 +0000

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