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
