I have ScaledDecimal, based on the ANSI Smalltalk standard, but fixed point decimal arithmetic, because that's what the ANSI Smalltalk standard calls for (citing a non-existent part of the LIA standard) but contradicts
FixedPoint, a version of that specifically intended for plugging into Squeak and/or Pharo, the snag being that I don't seem to have kept the change set, just the master. I can recreate and donate the change set if anyone would like it. PackedDecimal, which just models VisualAge 31-digit packed decimal for interoperability, but does not do arithmetic. On Tue, 31 Aug 2021 at 19:44, Guillermo Polito <guillermopol...@gmail.com> wrote: > > Hi all, > > In the past months I worked a bit with it and found many problems too, like: > - doing scaled decimal arithmetics losing precision > https://github.com/pharo-project/pharo/issues/8668 > - strange default scale values > https://github.com/pharo-project/pharo/issues/8669 > > I also got hit with “downgrading" issues during my vacation coding. For > example, when operating a scaled decimal with a float, the result gets > downgraded to a float. > See > > 17.777 asScaledDecimal + 0.0 > > From all the comments I understand that the current implementation is not > very useful, they all lead to “do not use it, instead do XXX” where XXX is > either > - write your own > - load that other package > - use an integer to represent pennies > > This this means that either it can be removed, or it can benefit with a new > and better implementation. > I think it would be interesting to have a better ScaledDecimal > implementation, that not only does precise printing but also precise > arithmetics. > > Or maybe somebody has a good implementation already available? > > Cheers, > Guille > > > El 31 ago 2021, a las 0:58, Richard O'Keefe <rao...@gmail.com> escribió: > > > > Ah, you have run into the insufficiently well known > > "ScaledDecimal looks like what you need but isn't". > > > > In VisualAge, you have a data type that is basically a reflection of iBM > > mainframe "packed decimal" format, and perfectly suits the needs of > > an SQL or COBOL interface. It gives you round-tripping with no error. > > > > In my Smalltalk, ScaledDecimal is a pair (n,s) where n and s are > > unrestricted integers, representing n * (10 raisedTo: s). This also > > gives you exact round-tripping and suits the needs of an SQL or COBOL > > interface. > > > > However, in Squeak and Pharo, ScaledDecimal is something else > > entirely. Basically, a pair (q,s) where q is an Integer or Fraction, > > and s is a scale factor used for *printing*. This doesn't just lead to > > oddities like two unequal ScaledDecimals printing identically, it > > leads to rounding issues. This is not a bug, it is ScaledDecimal working > > as designed. > > > > Working within Squeak, the simplest approach is to represent money as > > pence, and the next simplest is to make or find a Money class. > > > > On Tue, 31 Aug 2021 at 00:02, David Pennington <da...@totallyobjects.com> > > wrote: > >> > >> Hi everyone. I have a little bank analysis package for my own use but > >> having trouble displaying and storing amounts. I parse out a CSV file from > >> the bank and convert the amounts from text to ScaledDecimal. I then store > >> these into a STON file, which converts them back to text. I then read them > >> in and convert them back to ScaledDecimal again. > >> > >> I am not used to ~Pharo have spent 24 years using VisualAge Smalltalk so I > >> need a little bit of help because I am getting 1 Penny errors in the > >> conversions. I can cope with this but I would like to get it right. > >> > >> Can anyone give me a simple means of managing, say, an amount like £76.49 > >> from the bank so that it stops coming back to me as £76.48? > >> > >> David > >> Totally Objects
