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Re: Silly question about storing and displaying currency amounts?

by David Pennington

I come from a currency trader background and way back in 1983, I was dealing with this in North Star Basic and then UCSD Pascal and into VisualSmalltalk (remember that?) so I have some history here. Trouble is, at 76, my little grey cells are letting me down bit. Excuses over. I will go back into the code and make sure that I scale all these ScaledDecimals to 2 and see if that helps. BTW, I wasnât suggesting that there was any problem with STON as that works brilliantly for me. David > On 30 Aug 2021, at 13:51, jtuchel(a)objektfabrik.de wrote: > > Hi Sven, > > > I just tried 46.79 asScaledDecimal and 46.79 asScaledDecimal: 2 in both VAST and Pharo and see quite different results. > In VAST, not providing a scale returns 46.79, but with a scale of 14 (46.79s14). But it is still 46.79. > > What's good is that the results of "asScaledDecimal: 2" yields the same results on VAST and Pharo. > > Your examples also use a fixed scale of 2. So is it safe to assume that when you provide the scale, ScaledDecimal is good for monetary amounts in Pharo? I ask because that is what I once learned in an IBM training decades ago: use ScaledDecimals for money and percentages, never use floats. > > Would you agree that as a rule of thumb, Pounds, Dollars and Euros are safely stored and processed when you make sure to always provide the scale of 2 (unless you manage stock or petrol prices which use 3 or 4 or even more digits)? > > Joachim > > > > > > Am 30.08.21 um 14:31 schrieb Sven Van Caekenberghe: >> David, >> >>> On 30 Aug 2021, at 14:02, David Pennington <david(a)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 Â£76.49 from the bank so that it stops coming back to me as Â£76.48? >>> >>> David >>> Totally Objects >> Working with money is always challenging. I know that many people say 'Use ScaledDecimal' as if that magically solves all problems but it does not. ScaledDecimal is a bit of a dangerous class to use. It is just a fraction with a certain precision. Internally it might be pretty accurate with respect to most operations, its external representation as floating point number can be misleading, as this representation is prone to all problems related to floating point (including the fact that decimal and binary floating point are not the same). >> >> STON does not doing anything wrong as far as I know. Consider the following: >> >> | amount ston | >> amount := 76.49 asScaledDecimal. >> ston := STON toString: amount. >> STON fromString: ston. >> (STON fromString: ston) = amount. >> "true" >> >> | amount ston | >> amount := 76.49 asScaledDecimal: 2. >> ston := STON toString: amount. >> STON fromString: ston. >> (STON fromString: ston) = amount. >> "true" >> >> | amount ston | >> amount := 76.49. >> ston := STON toString: amount. >> STON fromString: ston. >> (STON fromString: ston) = amount. >> "true" >> >> BUT, 76.49 asScaledDecimal already has your penny loss (if rounded to pennies). >> >> HTH, >> >> Sven >> > > -- > ----------------------------------------------------------------------- > Objektfabrik Joachim Tuchel mailto:jtuchel@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 >

Aug. 30, 2021

Re: Silly question about storing and displaying currency amounts?

by Sabine Manaa

http://smalltalkhub.com/pdebruic/Money/index.html Am Mo., 30. Aug. 2021 um 14:51 Uhr schrieb jtuchel(a)objektfabrik.de < jtuchel(a)objektfabrik.de>: > Hi Sven, > > > I just tried 46.79 asScaledDecimal and 46.79 asScaledDecimal: 2 in both > VAST and Pharo and see quite different results. > In VAST, not providing a scale returns 46.79, but with a scale of 14 > (46.79s14). But it is still 46.79. > > What's good is that the results of "asScaledDecimal: 2" yields the same > results on VAST and Pharo. > > Your examples also use a fixed scale of 2. So is it safe to assume that > when you provide the scale, ScaledDecimal is good for monetary amounts > in Pharo? I ask because that is what I once learned in an IBM training > decades ago: use ScaledDecimals for money and percentages, never use > floats. > > Would you agree that as a rule of thumb, Pounds, Dollars and Euros are > safely stored and processed when you make sure to always provide the > scale of 2 (unless you manage stock or petrol prices which use 3 or 4 or > even more digits)? > > Joachim > > > > > > Am 30.08.21 um 14:31 schrieb Sven Van Caekenberghe: > > David, > > > >> On 30 Aug 2021, at 14:02, David Pennington <david(a)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 > Â£76.49 from the bank so that it stops coming back to me as Â£76.48? > >> > >> David > >> Totally Objects > > Working with money is always challenging. I know that many people say > 'Use ScaledDecimal' as if that magically solves all problems but it does > not. ScaledDecimal is a bit of a dangerous class to use. It is just a > fraction with a certain precision. Internally it might be pretty accurate > with respect to most operations, its external representation as floating > point number can be misleading, as this representation is prone to all > problems related to floating point (including the fact that decimal and > binary floating point are not the same). > > > > STON does not doing anything wrong as far as I know. Consider the > following: > > > > | amount ston | > > amount := 76.49 asScaledDecimal. > > ston := STON toString: amount. > > STON fromString: ston. > > (STON fromString: ston) = amount. > > "true" > > > > | amount ston | > > amount := 76.49 asScaledDecimal: 2. > > ston := STON toString: amount. > > STON fromString: ston. > > (STON fromString: ston) = amount. > > "true" > > > > | amount ston | > > amount := 76.49. > > ston := STON toString: amount. > > STON fromString: ston. > > (STON fromString: ston) = amount. > > "true" > > > > BUT, 76.49 asScaledDecimal already has your penny loss (if rounded to > pennies). > > > > HTH, > > > > Sven > > > > -- > ----------------------------------------------------------------------- > Objektfabrik Joachim Tuchel mailto:jtuchel@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 > >

Aug. 30, 2021

Re: Silly question about storing and displaying currency amounts?

by jtuchel＠objektfabrik.de

Hi Sven, I just tried 46.79 asScaledDecimal and 46.79 asScaledDecimal: 2 in both VAST and Pharo and see quite different results. In VAST, not providing a scale returns 46.79, but with a scale of 14 (46.79s14). But it is still 46.79. What's good is that the results of "asScaledDecimal: 2" yields the same results on VAST and Pharo. Your examples also use a fixed scale of 2. So is it safe to assume that when you provide the scale, ScaledDecimal is good for monetary amounts in Pharo? I ask because that is what I once learned in an IBM training decades ago: use ScaledDecimals for money and percentages, never use floats. Would you agree that as a rule of thumb, Pounds, Dollars and Euros are safely stored and processed when you make sure to always provide the scale of 2 (unless you manage stock or petrol prices which use 3 or 4 or even more digits)? Joachim Am 30.08.21 um 14:31 schrieb Sven Van Caekenberghe: > David, > >> On 30 Aug 2021, at 14:02, David Pennington <david(a)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 Â£76.49 from the bank so that it stops coming back to me as Â£76.48? >> >> David >> Totally Objects > Working with money is always challenging. I know that many people say 'Use ScaledDecimal' as if that magically solves all problems but it does not. ScaledDecimal is a bit of a dangerous class to use. It is just a fraction with a certain precision. Internally it might be pretty accurate with respect to most operations, its external representation as floating point number can be misleading, as this representation is prone to all problems related to floating point (including the fact that decimal and binary floating point are not the same). > > STON does not doing anything wrong as far as I know. Consider the following: > > | amount ston | > amount := 76.49 asScaledDecimal. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > | amount ston | > amount := 76.49 asScaledDecimal: 2. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > | amount ston | > amount := 76.49. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > BUT, 76.49 asScaledDecimal already has your penny loss (if rounded to pennies). > > HTH, > > Sven > -- ----------------------------------------------------------------------- Objektfabrik Joachim Tuchel mailto:jtuchel@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

Aug. 30, 2021

Re: Silly question about storing and displaying currency amounts?

by Esteban Lorenzano

hi, some time ago there was a "money" package around, that basically had a Currency type that internally stored values as integers (like, 42.0 was becoming 4200). This had some advantages to make this kind of calculus (also, it has the "other" advantage of making you believe that you have a lot more money than what you have ;). maybe you need to go that direction? Esteban On Aug 30 2021, at 2:31 pm, Sven Van Caekenberghe <sven(a)stfx.eu> wrote: > David, > > > On 30 Aug 2021, at 14:02, David Pennington <david(a)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 Â£76.49 from the bank so that it stops coming back to me as Â£76.48? > > > > David > > Totally Objects > > Working with money is always challenging. I know that many people say 'Use ScaledDecimal' as if that magically solves all problems but it does not. ScaledDecimal is a bit of a dangerous class to use. It is just a fraction with a certain precision. Internally it might be pretty accurate with respect to most operations, its external representation as floating point number can be misleading, as this representation is prone to all problems related to floating point (including the fact that decimal and binary floating point are not the same). > STON does not doing anything wrong as far as I know. Consider the following: > | amount ston | > amount := 76.49 asScaledDecimal. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > | amount ston | > amount := 76.49 asScaledDecimal: 2. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > | amount ston | > amount := 76.49. > ston := STON toString: amount. > STON fromString: ston. > (STON fromString: ston) = amount. > "true" > > BUT, 76.49 asScaledDecimal already has your penny loss (if rounded to pennies). > HTH, > Sven

Aug. 30, 2021

Re: Silly question about storing and displaying currency amounts?

by Sven Van Caekenberghe

David, > On 30 Aug 2021, at 14:02, David Pennington <david(a)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 Â£76.49 from the bank so that it stops coming back to me as Â£76.48? > > David > Totally Objects Working with money is always challenging. I know that many people say 'Use ScaledDecimal' as if that magically solves all problems but it does not. ScaledDecimal is a bit of a dangerous class to use. It is just a fraction with a certain precision. Internally it might be pretty accurate with respect to most operations, its external representation as floating point number can be misleading, as this representation is prone to all problems related to floating point (including the fact that decimal and binary floating point are not the same). STON does not doing anything wrong as far as I know. Consider the following: | amount ston | amount := 76.49 asScaledDecimal. ston := STON toString: amount. STON fromString: ston. (STON fromString: ston) = amount. "true" | amount ston | amount := 76.49 asScaledDecimal: 2. ston := STON toString: amount. STON fromString: ston. (STON fromString: ston) = amount. "true" | amount ston | amount := 76.49. ston := STON toString: amount. STON fromString: ston. (STON fromString: ston) = amount. "true" BUT, 76.49 asScaledDecimal already has your penny loss (if rounded to pennies). HTH, Sven

Aug. 30, 2021

Silly question about storing and displaying currency amounts?

by David Pennington

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 Â£76.49 from the bank so that it stops coming back to me as Â£76.48? David Totally Objects

Aug. 30, 2021

Re: The ideal font for Pharo

by Guillermo Polito

Hi tau, Thanks for it, Iâll check it :) > El 26 ago 2021, a las 1:17, tau <tau(a)cedalion.info> escribiÃ³: > > I've been bothered by the assignement operator (:=) and the way the colon and the equal sign aren't verticaly aligned when coding in Pharo. So I began a quest to find a pharo-friendly font were the colon and equal sign are aligned. Turn out most monospaced fonts don't qualify but I did find the following fonts: > > Fira Code (https://fontlibrary.org/en/font/fira-code <https://fontlibrary.org/en/font/fira-code>) has a := ligature that doesn't work in Pharo. > Iosevka extended (https://fontlibrary.org/en/font/iosevka-extended <https://fontlibrary.org/en/font/iosevka-extended>) also has a := ligature that doen't work in Pharo. > Mononoki (https://fontlibrary.org/en/font/mononoki <https://fontlibrary.org/en/font/mononoki>) has the two characters properly aligned but I dislike the appareance of that font. The @, in particular, looks like it comes from a low-resolution terminal from the early '80s. > Fantasque Sans Mono (https://fontlibrary.org/en/font/fantasque-sans-mono <https://fontlibrary.org/en/font/fantasque-sans-mono>) has perfectly aligned colon and equal sign and moreover has a nice informal look. > > So, Fantasque Sans Mono is now my favorite font for coding in Pharo ð.

Aug. 30, 2021

Re: uFFI: Calling conventions?

by Guillermo Polito

Hi egarrulo, > El 27 ago 2021, a las 18:50, egarrulo <egarrulo(a)gmail.com> escribiÃ³: > > >> Yesterday we have implemented the image side part in P10 to correctly > honour the calling convention. > > Does this imply that uFFI doesn't work correctly on current images? > Because uFFI should have been available since Pharo 8, according to the > uFFI manual. Or is it a revamped implementation? Calling conventions are properly working, but I think that what Pablo means is something else. The current implementation just uses the most common (which is the sole in most cases) calling convention for the platform. What Pablo meant I think is that the current implementation does not allow users to redefine the calling convention. > >> On the other hand, you are asking about ThisCall. This calling > conventionis only relevant in 32bits systems. What is your target > system/library? Does it not exist as 64-bit library? > > Unfortunately it is a legacy library with no 64 bit version. No problem, > because I can write a wrapper, yet I was wondering if Pharo offered any > facilities to avoid that. Check Pabloâs PR https://github.com/pharo-project/pharo/pull/9826 The class TFUFFIDifferentCallingConventionFunctionCallTest uses the ffiCallingConvention hook to decide what calling convention to use. Check the list in initializeABIMapping to see the available calling conventions. Cheers, G > > Thank you for the information. > > ---------------------------------------------------------------------- >> Message: 1 >> Date: Thu, 26 Aug 2021 15:38:48 +0200 >> From: "tesonep(a)gmail.com" <tesonep(a)gmail.com> >> Subject: [Pharo-users] Re: uFFI: Calling conventions? >> To: Any question about pharo is welcome <pharo-users(a)lists.pharo.org> >> Message-ID: >> <CAM9-ED+DYAJdOF0GfBcypmV9cQqufmSzUmC51EaLRzS2ycsPWQ(a)mail.gmail.com> >> Content-Type: multipart/alternative; >> boundary="0000000000004711e205ca767def" >> >> Hi All, >> The answer is yes and no. >> Let's go step by step. >> To declare the calling convention a class can override the method >> #ffiCallingConvention. Returning a Symbol representing the Calling >> Convention. >> >> Yesterday we have implemented the image side part in P10 to correctly >> honour the calling convention. >> I have implemented it for X86 but this can be easily extended to ARM32 >> (ARM64 has a single calling convention). >> If this fix is useful, it can be backported to P9. >> >> However, this only works for X86_64 as it depends on the new FFI >> implementation. We still do not have an X86 32 bits VM, it is possible to >> compile it from sources, but we are not distributing it. >> >> In X86_64 only exists the Windows and the GNU calling convention, we are >> supporting both. >> >> On the other hand, you are asking about ThisCall. This calling convention >> is only relevant in 32bits systems. What is your target system/library? >> Does it not exist as 64-bit library? >> >> Thanks >> >> On Tue, Aug 24, 2021 at 9:33 PM egarrulo <egarrulo(a)gmail.com> wrote: >> >>> Hi all, >>> >>> I haven't found any information on calling conventions in the "Unified >>> FFI - Calling Foreign Functions from Pharo" manual. What conventions are >>> available, please? >>> >>> If the ThisCall[1] convention isn't supported, could it be implemented >>> in code with some boilerplate? >>> >>> Thank you. >>> >>> -- >>> >>> [1] ThisCall works like StdCall, but the first parameter - the "this" >>> pointer - is passed via the ECX register. >>> >>>

Aug. 30, 2021

Re: Using new VM but can't find any log files

by David Pennington

Sven Thanks for your response. I had the same problem on 8.0 and, in fact, had the same problem with VAST on Windows 10 and Windows 2012 server so I am not hopeful. Running Linux is not an option for me although I could reconfigure my Windows 2012 Server as I have replaced that with an M1 MacMini. For the time being, my client (or at least the club that I belong to, appreciate my efforts and are happy with as minimal HTML web site and a Blog but I got the MacMini hoping to solve this so I would like to see a solution. I am enjoying Pharo and donât want. To have to leave it. David > On 28 Aug 2021, at 16:47, David Pennington <david(a)totallyobjects.com> wrote: > > Hi there. I have installed the new M1 VM that supposedly gives much better information into a log file. However, my image is still disappearing such that it now doesnât last more than 12 hours before going. I have searched for these log files but I canât find any. Can anyone help me in this as I am close the throwing this all into the bin if I canât keep my simple web site going regularly. My clients are not happy, as you can imagine and telling me to just go with a Blogger blog! I donât want to do that so can anyone help? > David

Aug. 28, 2021

Re: Using new VM but can't find any log files

by Sven Van Caekenberghe

David, > On 28 Aug 2021, at 17:47, David Pennington <david(a)totallyobjects.com> wrote: > > Hi there. I have installed the new M1 VM that supposedly gives much better information into a log file. However, my image is still disappearing such that it now doesnât last more than 12 hours before going. I have searched for these log files but I canât find any. Can anyone help me in this as I am close the throwing this all into the bin if I canât keep my simple web site going regularly. My clients are not happy, as you can imagine and telling me to just go with a Blogger blog! I donât want to do that so can anyone help? > David We are sorry that you have this problem. Many people have already interacted with you via various channels. Multiple Pharo developers are working on this issue (https://github.com/pharo-project/pharo/issues/9565) but right now there is no immediate solution. One option would be to go back to Pharo 7 or 8 (it is normally easy to have the same code base for Pharo 7, 8 and 9), but then you probably need to move away from M1 hardware. Another option would be to run your application under control of launchd (on macOS) os systemd (on Linux). These tools automatically restart your app when it goes down. This is something you need for proper production deployment anyway. In any case we are working on it and will surely let you know if we make progress. HTH, Sven

Aug. 28, 2021