Re: proposal to toss out text2interval. Was: dependent and independent intervals, proposal to toss out text2interval.
On 2013-02-27 22:22:41 +0100, Christian Keil wrote:
> Am Tue, 19 Feb 2013 12:37:40 -0800
> schrieb Richard Fateman <fateman@xxxxxxxxxxxxxxxxx>:
>
> > On 2/19/2013 2:00 AM, Guillaume Melquiond wrote:
> > .... snip, , expressions meaning what they say...
> >
> > I think that whatever advantage can be gained by allowing an
> > implementation to process string expressions like "0.1 + pi" is more
> [...]
>
> probably I'm missing something here. But where does the idea to allow
> "0.1 + pi" as an input to text2interval come from?
AFAIK, the idea of text2interval was not to write expressions
like "0.1 + pi", but rather text strings like "[0.1,0.2]" (or
just "0.1"?). IMHO, some common forms should be standardized.
Then there's the question whether implementation-defined alternate
forms should be allowed rather than specifying an error. I think
that this can be useful (and somewhat necessary) to construct
some intervals exactly, e.g. in case of a rational-based interval
implementation (one may want to write "[1/17,1/3]").
> There is also the mention of an language- or implementation-defined
> enhanced syntax which may includes other symbols for real constants
> like Pi in floating literals, but---besides this being language- or
> implementation-defined---nothing is expressions.
If what a symbol is isn't specified, you may see an expression
as a symbol.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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