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From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Fernando Cacciola Sent: Thursday, November 01, 2012 6:34 PM To: boost@lists.boost.org Subject: Re: [boost] [Numeric Conversion] Documentation Notes/Questions
That is needed to draw a distinction between the values that are represented and the effective value of the representation. I debated myself a lot whether such a concept was really needed, given how odd it is, or if there was a better way, but couldn't find it.
The problem is that, when talking about the effects of a numeric conversion, I need a thing that can be used to qualify and quantizie the difference between the (effectively represented) values before and after the conversion. That is, in "(int)1.2" there are just two represented values, the floating point that closely matches the decimal 1.2 and the integer 1, yet I need to refer to the .2 in there that is getting lost and a useful element to do that, IMO, is "the decimal number 1.2". I call that an abstract value.
I'm not clear why you have chosen to call this an 'abstract value'. 'decimal digit string' seems more explicit -though I can see that it might also be a hex of oct (or even bin) string. So would 'digit string value' be more immediately obvious? (It could be qualified as 'integer digit string'(99), 'decimal digit string' (1.2), 'fraction digit string' (.1234), 'hex integer digit string (FF), ...) But perhaps I'm missing something?
Without such a concept it is much more difficult to describe and bound *in general terms* the sides effects of conversions, such as loose of precision, overflow and underflow.
Definitely! This is confusing stuff. Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow@hetp.u-net.com