Squeak-dev November 2001

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174 participants
374 discussions

Re: [BUG] file Truncate is it really busted?
by Richard A. O'Keefe 29 Nov '01

29 Nov '01

woods(a)weird.com (Greg A. Woods) replied to my explanation of the 'f' prefixes in C file handling functions. Well there's also the fact that the two uses of the 'f' prefix are really in fundamentally different levels of the API -- or depending on your point of view maybe even completely different APIs. Fundamentally different? Some of them are in the kernel, and some of them are in the C stdio library, but from the point of view of your average UNIX programmer this is a distinction without a difference. open() and fopen() are *both* in POSIX. A UNIX look-alike could quite legitimately place fopen() in the kernel and open() in a library, just like it is on my Mac at home. (Yep, Think C layered the UNIX functions on top of the stdio functions, and they were layered on top of the MacOS ones.) The stdio library functions that have an 'f' prefix operate on FILE structures. The system calls that have an 'f' prefix operate on kernel file descriptors. Yes, I know. That's pretty much what I said. That's the PROBLEM. > It would make sense to have an fftruncate() function (truncate + > f prefix to get file descriptor + f prefix to get FILE*), but there is none. Actually, no, it doesn't -- but the reasons why depend on one having an intuitive understanding of the difference in API levels between the stdio library and raw system calls. The functions like fclose(), fread(), et al require a FILE* because they operate on the internal elements of a FILE structure. Non sequitur. The getchar(), getc(), putchar, putc(), printf(), and scanf() functions, amongst others, operate on the internal elements of a FILE structure, but don't have a FILE * argument. And the clearerr() and fileno() functions, amongst others, have a FILE * argument but don't have an "f" prefix. (fileno() begins with "f", but it's part of the word "file", not a prefix.) Some stdio functions with a FILE* prefix have an f prefix. Some don't. A uniform rule appears to have been applied to *both* the (2) and (3s) functions: if you want a file handling function, and there is already one with the name you want, stick an 'f' in front. Anyone looking for a deeper level of meaning is looking for consistency that just isn't there. By the way, I once wrote my own implementation of stdio, complete except for *scanf(), which I had no particular use for. If you want to use a system call on a file opened by stdio you simply access the file descriptor from the (opaque) FILE structure using the fileno() function. For many things it's not that simple, but everyone who has an intuitive understanding of the difference in API levels &c &c already knows that. I.e. there is no need to confuse stdio and system call naming conventions with ugly constructions like "fftruncate()" because it is already more properly done with ftruncate(fileno(FILE*)). I'm sorry, but this is precisely why it WOULD make sense to have fftruncate(), because ftruncate(fileno(fp)) just plain doesn't work. I *think* the following code will work, but of course it isn't portable to systems that don't have f{un,}lockfile(): int fftruncate(FILE *fp) { int r, e; flockfile(fp); fflush(fp); r = ftruncate(fileno(fp)); e = errno; funlockfile(fp); errno = e; return r; } Even this doesn't work if the last transput operation on the stream was an input operation; fflush() only makes the file position and the stream position agree when the last operation was not an input. In order to handle the input case, we'd have to seek back in the file to where the stream is (because of the buffered input), which is doable, *AND* we would have to mark the buffer as empty, which we can't do in a portable way. I could do it easily enough on any of the 32-bit UNIX systems I have access to, but it would not be portable, and it certainly wouldn't work with LFS 64-bit filesystems, because the vendors have taken care to hide the 64-bit filesystem FILE* record completely. A little learning is a dangerous thing...

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Hello
by Hans Kristian �ker�y 29 Nov '01

29 Nov '01

Hi. i ref to http://squeak.cs.uiuc.edu/mail/squeak/msg01711.html you are looking for a Game developing Team I am founder of 7th Exodus a Game developin team , tho we arten that mutch active , so i finaly started a littel project called Yellow Snow Project , if i get members that can develop , maby we can make games , i am currently learning c++ to make real games , tho i can make 2d\3d games , not great games but still , cool Rpg fanatic games .. :p not that can be compared to any real games :p but still cool . heh... look at http://yellow-snow.cjb.net/ if news and mail me if intrested , i hope i can make a great team and maby coem to the e3 soem day >From Hans kristian Åkerøy Co Founder & Admin of 7th Exodus - Site not up.... Founder and owner of Yellow Snow - http://yellow-snow.cjb.net/ _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

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Re: XML Parser choice (was Re: [ENH] ??? MD5 in Squeak.)
by Richard A. O'Keefe 29 Nov '01

29 Nov '01

"Duane Maxwell" <dmaxwell(a)san.rr.com> wrote: The exobox parser is a complete well-formedness, non-validating parser minus Unicode support - every obscure little syntax weirdness is handled, even if the result is eventually dropped on the floor. Having written a couple of well-formedness parsers (including one with Unicode support), let me plead with the Squeak community *not* to accept a non-validating XML parser. If you DON'T validate, it is DEAD EASY. There really isn't a lot to do. My SAX-style non-validating parser in C literally spends more time in the read() system call than everywhere else put together. When an XML parser runs about as fast as wc(1), you know that XML parsing can't be hard. (And yes, every single quirk I know of is handled.) There are actually three useful "grades" of parser, only two of which are covered by the XML 1.0 specification: - well-formedness checking (basically, do the brackets balance?) - semi-validation: resolve entity references, fill in #DEFAULT and #FIXED attribute values, know when an element allows #PCDATA content and when it doesn't, so that element-content white-space can be reliably discriminated from text in mixed content. - full validation: check that the document conforms to the DTD. If you can do semi-validation, you can handle XHTML and DocBook and other text formats. If you can't do semi-validation, you are *severely* limited in the range of XML that you can usefully handle. One big issue is that people seem to be extremely fond of indenting XML; this creates entirely bogus white space nodes _unless_ you either (x) like one parser I know, delete _all_ white space nodes, which gets a fair bit of text wrong, or (y) at least semi-validate. To take a simple example, consider <example> <warning>This doesn't seem to be indented but it is.</warning> <explanation>There are three white space nodes.</explanation> </example> Here is the ESIS for that example: (example => -\n (warning -This doesn't seem to be indented but it is. )warning => -\n (explanation -There are three white space nodes. )explanation => -\n )example I have flagged the white space nodes. In SGML, those white space nodes would simply not exist, DTD or no DTD. In XML, they do. And people think XML is simpler! With a DTD, <!ELEMENT example (warning,explanation*)+> <!ELEMENT warning (#PCDATA)> <!ELEMENT explanation (#PCDATA)> a validating or semi-validating XML parser would know to report those newlines as element-content white-space, which can safely be ignored and never built into an internal representation in the first place. You _can't_ get this right without looking at the DTD. We can cross those three grades with some variations: (1) Character set. Handle native character set only? Handle ISO Latin 1 only? Handle UTF-8 only? Handle the full range? My XML parser in C can be compiled to use Latin-1, UTF-8, UCS-2, or UCS-4 internally. The actual parsing code doesn't know and doesn't care. (Yes this means I will accept characters in element and attribute names that I shouldn't. But all that will happen is that illegal input will be accepted. No legal input will be rejected, and no legal input will be mis-parsed.) The decoding file dwarfs everything else. (2) Output method. Generate CXML text? Generate ESIS text? Generate Lisp, Erlang, Prolog text? Have SAX-*like* interface? Have exact SAX interface? Have DOM-*like* interface? Have exact DOM interface (not actually possible in C)? Have Lisp, Erlang, Prolog, Smalltalk interface? Have DVM interface? Have JDOM interface? My parser provides the options above the blank line, all based on the event-oriented interface (an idea older than SGML, but nowadays credited to SAX). Again, this code dominates the parsing code in size. A SAX-*like* (but not SAX) interface can be small and very easy to use. (3) Support for compression and encryption? (I leave this lot to your imagination. I do none of it.) (4) Support for SYSTEM identifiers? No support (document must be self-contained)? SYSTEM identifiers are just local file names? SYSTEM identifiers are (relative) file://localhost filenames, in URL syntax and converted to form required by host OS? SYSTEM identifiers are URIs including support for file:, ftp:, http:? SYSTEM identifiers are URIs including https: and SSH ftp? The main reason my parser doesn't semi-validate yet is that I've never written an FTP or HTTP client before; now that I've discovered the CURL library, my main problem may be solved. Needless to say, the CURL library is _enormous_ compared with everything else put together. The two operations you need are (a) Here is a base URI and another URI which may be relative or absolute; return second resolved relative to the first. (b) Here is a URI; return me an input stream reading its content or fail. (5) Support for PUBLIC identifiers? No support? Support for a handful of known PUBLIC identifiers such as XHTML and especially the XHTML entity sets? Support for PUBLIC identifiers using homebrew catalogues? Support for PUBLIC identifiers using OASIS catalogues? The last is very desirable if you want to handle DocBook or many of the things that XML is useful for, but it is about as difficult as well-formedness parsing of XML. The great thing about having an XML parser in Squeak is that the really hard stuff, like URI processing, compression, and encryption, can be kept out of your XML parsing code. If Squeak is to have an "official" XML parser, let it be one

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Re: XML Parser choice (was Re: [ENH] ??? MD5 in Squeak.)
by Richard A. O'Keefe 29 Nov '01

29 Nov '01

I wrote: : Non-validating parsers are easy to write. But if anyone were : to try to process DocBook using Squeak (hey, guess what I'm : trying to learn?) such a parser would be as much use as an : Apple ][ simulator (maybe less, come to think of it). "Duane Maxwell" <dmaxwell(a)san.rr.com> replied: Hey! I resent that! An Apple ][ emulator is *supremely* useless. It's useless in the way that operas and novels are useless. It's a work of craft which simultaneously pays homage to the past and revels in the accomplishments of the present. In fact, I challenge anyone to come up with something else in Squeak less useful. 12-bit hash codes? Or has that been fixed?

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[ENH] Update to Mouse Click Focus Policy option.
by Steve Swerling 28 Nov '01

28 Nov '01

[Note: Sorry if this message goes up more than once, I got an error in celeste trying to send it from the changesorter(501 Bad address syntax), probably something I did. Resending from netscape...]. This is an update to the MouseClickFocusPolicy option for morphic to bring it up-to-date with update #4554. Changes since last posting: - get it working with latest updates - fixes bug where text was deselected in the debugger - click in category list in Browser selects new method template and puts focus in the code pane. - Postscript no longer pops open an info window >From the preamble: "Change Set: spsFocusPolicy Date: 28 November 2001 Author: Steven Swerling This change set adds a preference called ""mouseClickFocusPolicy"" in the morphic tab of the preferences window. If unchecked, behavior is identical to the standard focus policy -- the pane that the mouse is over gets keyboard focus. If checked, the user must explicitly click in a pane to set the focus on that pane -- the location of the mouse does not effect where the keyboard focus goes. Changes since last posting: - get it working with latest updates - fixes bug where text was deselected in the debugger - click in category list in Browser selects new method template and puts focus in the code pane. "!

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[GOODIE] TwoInstruments
by Hans-Martin Mosner <hmm＠heeg.de> 28 Nov '01

28 Nov '01

from preamble: "Change Set: TwoInstruments Date: 28 November 2001 Author: Hans-Martin Mosner <hmm(a)heeg.de> Two simple FMSound instruments: 1. FMSound bellPiano sounds not totally unlike the Bell Piano voice in my Korg DS-8. 2. FMSound elecBass sounds a little like an electric bass guitar. Have fun!!"!

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Re: Squeak Teaching/Learning questions
by raymondasselin＠sympatico.ca 28 Nov '01

28 Nov '01

Jerry Balzano <gjbalzano(a)ucsd.edu> wrote: > Where my HyperCard background gets me in trouble with Squeak is when I'm > repeatedly wanting/trying to "lift the hood" on things to see how they > work, and my HC experience of how to do this and what you find there is > just different. For example, Squeak inspectors on object instances are > really only the tip of the iceberg, but browsing the class takes me all the > way to the bottom of the ocean. I need better moves for negotiating the > middle ground. > > So in HyperCard I could always double-click on a button, see its > point-clickable properties, and with one more click see the script for how > that button works. In Squeak I seem to only be able to see how a button > works in this way if it has been Etoy-scripted. Similarly with menu items: > I'd love to be able to "lift the hood" on one of the many menu items that > one can access through a morph's halos and peek at the code that implements > that function. How can I (or anyone else learning Squeak) do this? Hi Jerry I'm not an expert but I can share this with you. If I understand well what you are looking for, try this: a) In the World menu select 'object' and game category and pick up 'Tetris' Now you have a morph witch is'nt an Etoy one. b) Press Command key (on Mac) and click on the 'pause' button repeatedly until you saw 'button' as the name of the halos...this is 4 clics. c) Now with the 'debug' circle of the halo choose 'explore morph'. This will bring a kind of inspector which give you the structure (construction) of the main morph. In that inspector you'll see the actionSelector: '#pause' this message is sent to the target: 'a TetrisBoard' d) To know the implementation of the method 'pause' do this: Type 'TetrisBoard' in the bottom pane of the inspector, select it and do Command b keys. This will bring a Hierarchy Browser one the TetrisBoard Class. Once there, look for 'pause' on the right panel, select it and you'll see the code in the bottom panel. =================== An other way to do the same thing is: do the same a) b) and c) points....now you are in the explorer (the structure's inspector) and you know that the method (function) you are looking for is 'pause', so you can type pause in the bottom panel (or in an workspace) select it and press Command Shift w. This will bring a Messages Browser. Look for 'pause' in the left pane, select it and you'll see in the right pane the classes who implement such a message, as you know that the target of that message was TetrisBoard you just select it and you see the code in the bottom pane. > Another thing I haven't been able to figure out: How do I access or > reference a morph that I have created via direct manipulation? I know I > can get an inspector on it and call it "self" in the inspector's code pane > ((language, language, hope I'm expressing things correctly)), but how can I > actually write code that gets or sets something on that morph out of that > special context? > > - Jerry I don't know all the picture here, but I know you can pick a Workspace and in his window menu select 'create textual references to dropped morphs' and, drop your morph on the Workspace, you'll have a reference for this morph. > ------------------------- > Dr. Gerald J. Balzano > Teacher Education Program > Dept of Music > Laboratory for Comparative Human Cognition > Cognitive Science Program > UC San Diego > La Jolla, CA 92093 > (619) 822-0092 > gjbalzano(a)ucsd.edu Hope this help Raymond

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Re: [BUG] RE: [win32] JPEG2 plugin
by jmvuletich＠uolsinectis.com.ar 28 Nov '01

28 Nov '01

Could you send me the sample image and the script you used to display it? What Display depth are you using? Thanks Juan Manuel Vuletich > It seems like the fast jpeg reader (in Win2k) is treating black pixels > as though they are transparent. > > - Stephen > > > -----Original Message----- > > From: squeak-dev-admin(a)lists.squeakfoundation.org > > [mailto:squeak-dev-admin@lists.squeakfoundation.org] On > > Behalf Of Andreas Raab > > Sent: Tuesday, November 27, 2001 6:44 PM > > To: squeak-dev(a)lists.squeakfoundation.org > > Subject: [win32] JPEG2 plugin > > > > > > For those of you who can't wait; attached is the new plugin. > > Decompress it, drop it into your VM folder and go. > > > > Cheers, > > - Andreas > > > > >

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Re: Weather maps?
by Luciano Notarfrancesco 28 Nov '01

28 Nov '01

Some time ago started building geographical objects in Squeak. I got volcanos and cities (loaded from a local text file), and some online maps (US LandSat, EarthView, and the Xerox PARC map). I also can show earthqakes in real-time. Here are the urls I'm getting the maps from http://www.fourmilab.ch/cgi-bin/uncgi/Earth http://wmt.jpl.nasa.gov/cgi-bin/wmt.cgi http://pubweb.parc.xerox.com/map The second one, wmt.jpl.nasa.gov uses a new standard, the Web Mapping Testbed. It's been a long time since the last time I checked, but I'm sure there are many more online maps in that format now. I'll clean the code a little and release it soon if there's interest on it. Peace, Luciano.- Dan Ingalls wrote: > Folks - > > We now have access to network spelling correction and translation in Squeak. Something else I like to see sometimes is an animation of the last 6 weather satellite images of my area at 1/2-hour intervals. Weather.com provides this nicely, but it would be even nicer to have it in Squeak, and separate from all the ads and inaccurate forecasts. Plus it galls me that they don't cache the background image of the ground (I think) -- it should be able to ship the precipitation overlays in just a couple of seconds, but it seems to take quite a long time. > > Anyone know enough to put this together? > > TIA > - Dan > > > __________________________________________________ Do You Yahoo!? Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month. http://geocities.yahoo.com/ps/info1

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[GOODIES] A little improvement of VWXML Squeak
by Masashi Umezawa 28 Nov '01

28 Nov '01

Hi, A little improvement of VWXMLParser has been put on my site. Please try. http://www.mars.dti.ne.jp/~umejava/smalltalk/soapOpera/index.html Basically, there are only minor changes. - cs files were divided so that they may be easy to extend. - file out was carried out in Squeak3.0. BTW: >From a SOAP developer's point of view, I think we will need more neutral (and simple) XML API for Smalltalk. If common protocols for XML processing are defined, we can swap many XML parser implementations. Best regards, --- [:masashi | ^umezawa]

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