On 02 Jun 2014, at 09:34, jtuc...@objektfabrik.de wrote: > Hi, > > VA Smalltalk comes with ScaledDecimal, and as far as I know, it always print > out the scale of a number, because it could be something like 0.5s3. And I'd > guess ScaledDecimal or FixedPoint are pretty common, because the use of this > class has been encouraged for the modelling of monetary amounts for decades > now.
Yes, I realise it is important in some contexts, that is why I added it now. Apart from the class name, another issue is that 0.5s3 prints as 0.500s3 in Pharo, the trailing zeros are possibly not added everywhere. > Joachim > > Am 02.06.14 01:51, schrieb José Comesaña: >> Hi Sven. >> >> First of all, I know that in VisualWorks there exists a class called >> FixedPoint, that is (more or less) similar to ScaledDecimal (is what the >> class comment says). But, instead of 123.45s2, VWs writes 123.45s. >> NEVERTHELESS, it can read 123.45s2 with no pain. >> >> There exists a Fraction type also in VW, which, I believe, uses the same >> notation as in Pharo. >> >> I know that portability is an important issue, but, at least for me, >> portability from Pharo to Pharo is the most important. I depend on >> ScaledDecimal for an application (for storing money values -changing the >> storage mode is not an option now-) and need the possibility of converting >> it to string and reading it back. The string version is my database, that >> gets loaded into memory upon program start. >> >> You can see here the changes I have made to STONReader >>#parseNumber: >> >> parseNumber >> | negated number | >> negated := readStream peekFor: $-. >> number := self parseNumberInteger. >> (readStream peekFor: $.) >> ifTrue: [ number := number + self parseNumberFraction ]. >> " -------------- >> New from here >> -------------- >> " >> >> (readStream peekFor: $s) >> ifTrue: [ | scale | >> scale := self parseNumberInteger. >> number := ScaledDecimal newFromNumber: number scale: scale ]. >> (readStream peekFor: $/) >> ifTrue: [ | denominator | >> denominator := self parseNumberInteger. >> number := Fraction numerator: number denominator: denominator ]. >> " -------------- >> to here >> -------------- >> " >> >> ((readStream peekFor: $e) or: [ readStream peekFor: $E ]) >> ifTrue: [ number := number * self parseNumberExponent ]. >> negated >> ifTrue: [ number := number negated ]. >> self consumeWhitespace. >> ^ number >> >> I am a newbie about STON. I don't know if it is correct, but it works for >> me, at least for some tests I have made. I know it needs improvements, >> thinking about strange strings we could receive. But I trust the writer not >> to create such weird things. >> >> I could suggest another way of making the function of parseNumber (OK, OK, I >> know I am thinking from a Pharo-only perspective...). Seeing that number >> parsing always ends with this condition: >> >> readStream atEnd not and: [ readStream peek isDigit ] >> >> why not create a temporary string (including possibility of $e, $s, $/, even >> $@ ...) to that point (tmpString) and do: >> >> number := Number readFromString: tmpString >> >> That way, we would have a "native" parsing in each language >> >> Hope this helps. If someone needs more information, pleas ask. >> >> Best regards >> >> >> >> 2014-05-31 21:29 GMT+02:00 Sven Van Caekenberghe <s...@stfx.eu>: >> Hi José, >> >> On 31 May 2014, at 01:32, José Comesaña <jose.comes...@gmail.com> wrote: >> >> > Wouldn't it be good if STON could save ScaledDecimals as 12345.678s?. That >> > way, we could read them back again as ScaledDecimal, instead of Float. I >> > have tried and it seems quite useful. >> > >> > Regards >> >> That is an interesting idea and it is probably nice to have for those >> relying on ScaledDecimals. >> >> One of the ideas of STON is to be portable across dialects, so I am >> wondering if ScaledDecimals exists everywhere ? >> >> I am curious as to how you did it though, since STONReader basically >> contains its own number parser. Could you share your code ? >> >> Sven >> > > > -- > ----------------------------------------------------------------------- > Objektfabrik Joachim Tuchel > mailto:jtuc...@objektfabrik.de > > Fliederweg 1 > http://www.objektfabrik.de > > D-71640 Ludwigsburg > http://joachimtuchel.wordpress.com > > Telefon: +49 7141 56 10 86 0 Fax: +49 7141 56 10 86 1 > >
