[erlang-bugs] float parsing bug

Patrick Baggett <>
Wed Jan 13 02:18:05 CET 2010


Wings3D?

On Mon, Jan 11, 2010 at 12:34 PM, Robert Virding <> wrote:

> 2010/1/10 Ulf Wiger <>
>
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> > Alexander Borovsky wrote:
> > >
> > > 42.0 could have text representation "42".
> > >
> > > In most languages (C, Java, Ruby, etc) "42" parsed to float with no
> > errors.
> > >
> > > Also in some cases float values could be outputted with no decimal
> point:
> >
> > This is why I wrote "arguably". :)
> >
> > The question has been up on the mailing list before:
> >
> > http://www.erlang.org/cgi-bin/ezmlm-cgi?4:msp:15372:bkelgefglpkakhbedlbf
> > (May 12 2005)
> > http://www.erlang.org/cgi-bin/ezmlm-cgi/4/27647 (Jul 3 2007)
> > http://www.erlang.org/cgi-bin/ezmlm-cgi/4/37899 (Sep 4 2008)
> >
> > In the last one, Richard Carlsson wrote:
> >
> >  It's a "feature": list_to_float/1 is a rather low level function,
> >  which assumes that you have already checked that the string has the
> >  proper form for an Erlang float, i.e., "0.0" and "1.0E-3" are ok,
> >  but "22", ".0", and "0." are not.
> >
> > But you're definitely not the first one to disagree with this design
> > decision.
> >
>
> I *knew* it was a mistake to add floats in the first place. If NASA can hit
> the moon without them why should we need them for a telephone exchange or
> serving up a few pages on the web?
>
> Robert
>


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