2011/5/19 Dario Trussardi <dario.trussardi@tiscali.it>:

Hi,

       i found some problem into Gemstone relative to   SIXX support for manage ScaledDecimal instances.

       I do some test into Pharo and i found error when i read the sixx declaration relative to ScaledDecimal :

               <sixx.object sixx.id="0" sixx.type="ScaledDecimal" >123.456s3</sixx.object>

       For solve this error i define the ScaledDecimal :

               readSixxContentStringFrom: aStream

                       | numerator scale |

                       numerator := aStream upTo: $s .

                       scale := aStream upToEnd.

                       ^ self newFromNumber:  numerator asNumber scale: scale asNumber

Now my doubt is relative to string size and performance.

A)      If i write

               <sixx.object sixx.id="0" sixx.type="ScaledDecimal" >123.456s3</sixx.object>

       i have small string in sixx declartion but when create a ScaledDecimal from sixx the system execute the:

               newFromNumber: aNumber scale: anInteger                        | aFraction |                        aFraction := aNumber asFraction.                        ^aFraction isFraction                        ifTrue: [self new setNumerator: aFraction numerator denominator: aFraction denominator scale: anInteger]                        ifFalse: [self new setNumerator: aFraction denominator: 1 scale: anInteger]

       What is the performance relative to :                   aFraction := aFloat asFraction.    ????

Don't know about sixx, but one thing is sure, you can't use a Float, otherwise you'll loose precision. Float are inexact. In modern Squeak/Pharo you can check this 0.1s1 ~= 0.1. 0.1s1 = (1/10). 0.1 ~= (1/10). Nicolas

B)      The alternative is to write a sixx declaration with:

               <sixx.object sixx.id="0" sixx.type="ScaledDecimal" >(8687443681197687/70368744177664s3)</sixx.object>

       in this case the sixx string is big but the ScaledDecimal instance creation is direct:

               readSixxContentStringFromA: aStream

                       " with numerator and denominator "                | numerator denominator scale |                aStream next. "skip $("                numerator := aStream upTo: $/ .                denominator := aStream upTo: $s.                scale := aStream upTo: $).

               ^ self new setNumerator:  numerator asNumber denominator: denominator asNumber scale:  scale asNumber

Any pointers would be greatly appreciated !

       Thanks,

               Dario