Subject: printing money in C++ and in Common Lisp From: Erik Naggum <email@example.com> Date: 1998/05/06 Newsgroups: comp.lang.lisp Message-ID: <firstname.lastname@example.org> the April, 1998 issue of the C/C++ Users Journal has an interesting piece. (don't ask me how I got it or why I read it.) P.J.Plauger writes an insanely elaborate article on how to print money values nicely in C++ using advanced new features in the language that very few implement, something called "facets" and having to do with the horribly kludge they call "locale". it's part of the Standard C++ Library. of course. we're treated to a wonderfully eloquent statement of language power, and I quote: "The payoff is that the expression statement cout << showbase << setw(20) << internal << setfill('*') << Money(123456789.0) << endl; generates the output $*******1,234,567.89 Neat, huh?" yeah. neat. if you _love_ C++. Money is special wrapper class. the standard template class is called "money_put", which in order to work, needs some incredibly hairy setup work: 66 lines beyond the above "beauty", including some cut-and-paste code from elsewhere, because it is apparently hard to get all the details right. the implementation of the money_put template class takes 145 lines of unbelievable cruftiness. so I raised the Lisp Listener window in Allegro CL and I typed: (format t "~20,'*/dollars/" 123456789/100) (I posted the DOLLARS function here on 1997-08-12 as a quick response to a question of formatting money -- it took me mere minutes to write) and, lo and behold, it generated the output $*******1,234,567.89 very pleased with my 13-line (plus documentation) function, I just _had_ to use an all-standard FORMAT expression, too, using an integral number of cents, as in the article: (multiple-value-call #'format t "$~V,'*:D.~2,'0D" (- 20 4) (floor 123456789 100)) and, voilà, it generated the output $*******1,234,567.89 OK, so what _is_ wrong with this picture? object-orientation, C++ style. _that's_ wrong. the article was worth reading to see how fundamentally screwed-up C++ _people_ are, too. this stuff is ideally suited to a data-driven design, a miniature "language" that can describe a locale's conventions succinctly, _without_ using virtual functions to return a dollar sign, a plus sign, a minus sign, a comma, a decimal point, etc, but _no_, this is C++. we don't have data, we have code. lots and lots of code. P.J.Plauger himself laments the tall costs. I can only concur. if you think I'm exaggerating when I say that C++ is _fundamentally_ ill-designed and is only really suited to unethical programmers, this article may change your mind. the _code_ may change your mind. that this crap is part of the Standard C++ Library may change your mind. for kicks, I have extracted the files from the CUJAPR98.ZIP file at WWW.CUJ.COM and made the files insert.cpp and money_put.h (cleansed of DOS line ending CRuft, too, but FTP should add them back if you need them) available under ftp.naggum.no:/pub. (copyright in that code is assumed to remain with P.J.Plauger, although no notices are included.) #:Erik -- Support organized crime: use Microsoft products!