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@@ -0,0 +1,381 @@ +Tcl + +SCCS: @(#) README 1.52 97/11/20 12:43:16 + +1. Introduction +--------------- + +This directory and its descendants contain the sources and documentation +for Tcl, an embeddable scripting language. The information here +corresponds to release 8.0p2, which is the second patch update for Tcl +8.0. Tcl 8.0 is a major new release that replaces the core of the +interpreter with an on-the-fly bytecode compiler to improve execution +speed. It also includes several other new features such as namespaces +and binary I/O, plus many bug fixes. The compiler introduces a few +incompatibilities that may affect existing Tcl scripts; the +incompatibilities are relatively obscure but may require modifications +to some old scripts before they can run with this version. The compiler +introduces many new C-level APIs, but the old APIs are still supported. +See below for more details. This patch release fixes various bugs in +Tcl 8.0; there are no feature changes relative to Tcl 8.0. + +2. Documentation +---------------- + +The best way to get started with Tcl is to read one of the introductory +books on Tcl: + + Practical Programming in Tcl and Tk, 2nd Edition, by Brent Welch, + Prentice-Hall, 1997, ISBN 0-13-616830-2 + + Tcl and the Tk Toolkit, by John Ousterhout, + Addison-Wesley, 1994, ISBN 0-201-63337-X + + Exploring Expect, by Don Libes, + O'Reilly and Associates, 1995, ISBN 1-56592-090-2 + +The "doc" subdirectory in this release contains a complete set of reference +manual entries for Tcl. Files with extension ".1" are for programs (for +example, tclsh.1); files with extension ".3" are for C library procedures; +and files with extension ".n" describe Tcl commands. The file "doc/Tcl.n" +gives a quick summary of the Tcl language syntax. To print any of the man +pages, cd to the "doc" directory and invoke your favorite variant of +troff using the normal -man macros, for example + + ditroff -man Tcl.n + +to print Tcl.n. If Tcl has been installed correctly and your "man" +program supports it, you should be able to access the Tcl manual entries +using the normal "man" mechanisms, such as + + man Tcl + +There is also an official home for Tcl and Tk on the Web: + http://sunscript.sun.com +These Web pages include information about the latest releases, products +related to Tcl and Tk, reports on bug fixes and porting issues, HTML +versions of the manual pages, and pointers to many other Tcl/Tk Web +pages at other sites. Check them out! + +3. Compiling and installing Tcl +------------------------------- + +This release contains everything you should need to compile and run +Tcl under UNIX, Macintoshes, and PCs (either Windows NT, Windows 95, +or Win 3.1 with Win32s). + +Before trying to compile Tcl you should do the following things: + + (a) Check for a binary release. Pre-compiled binary releases are + available now for PCs, Macintoshes, and several flavors of UNIX. + Binary releases are much easier to install than source releases. + To find out whether a binary release is available for your + platform, check the home page for SunScript + (http://sunscript.sun.com) under "Tech Corner". Also, check in + the FTP directory from which you retrieved the base + distribution. Some of the binary releases are available freely, + while others are for sale. + + (b) Make sure you have the most recent patch release. Look in the + FTP directory from which you retrieved this distribution to see + if it has been updated with patches. Patch releases fix bugs + without changing any features, so you should normally use the + latest patch release for the version of Tcl that you want. + Patch releases are available in two forms. A file like + tcl8.0p2.tar.Z is a complete release for patch level 2 of Tcl + version 8.0. If there is a file with a higher patch level than + this release, just fetch the file with the highest patch level + and use it. + + Patches are also available in the form of patch files that just + contain the changes from one patch level to another. These + files will have names like tcl8.0p1.patch, tcl8.0p2.patch, etc. They + may also have .gz or .Z extensions to indicate compression. To + use one of these files, you apply it to an existing release with + the "patch" program. Patches must be applied in order: + tcl8.0p1.patch must be applied to an unpatched Tcl 8.0 release + to produce a Tcl 8.0p1 release; tcl8.0p2.patch can then be + applied to Tcl8.0p1 to produce Tcl 8.0p2, and so on. To apply an + uncompressed patch file such as tcl8.0p1.patch, invoke a shell + command like the following from the directory containing this + file: + patch -p < tcl8.0p1.patch + If the patch file has a .gz extension, invoke a command like the + following: + gunzip -c tcl8.0p1.patch.gz | patch -p + If the patch file has a .Z extension, it was compressed with + compress. To apply it, invoke a command like the following: + zcat tcl8.0p1.patch.Z | patch -p + If you're applying a patch to a release that has already been + compiled, then before applying the patch you should cd to the + "unix" subdirectory and type "make distclean" to restore the + directory to a pristine state. + +Once you've done this, change to the "unix" subdirectory if you're +compiling under UNIX, "win" if you're compiling under Windows, or +"mac" if you're compiling on a Macintosh. Then follow the instructions +in the README file in that directory for compiling Tcl, installing it, +and running the test suite. + +4. Summary of changes in Tcl 8.0 +-------------------------------- + +Here are the most significant changes in Tcl 8.0. In addition to these +changes, there are several smaller changes and bug fixes. See the file +"changes" for a complete list of all changes. + + 1. Bytecode compiler. The core of the Tcl interpreter has been + replaced with an on-the-fly compiler that translates Tcl scripts to + byte codes; a new interpreter then executes the byte codes. In + earlier versions of Tcl, strings were used as a universal + representation; in Tcl 8.0 strings are replaced with Tcl_Obj + structures ("objects") that can hold both a string value and an + internal form such as a binary integer or compiled bytecodes. The + new objects make it possible to store information in efficient + internal forms and avoid the constant translations to and from + strings that occurred with the old interpreter. We have not yet + converted all of Tcl to take full advantage of the compiler and + objects and have not converted any of Tk yet, but even so you + should see speedups of 2-3x on many programs and you may see + speedups as much as 10-20x in some cases (such as code that + manipulates long lists). Future releases should achieve even + greater speedups. The compiler introduces only a few minor changes + at the level of Tcl scripts, but it introduces many new C APIs for + managing objects. See, for example, the manual entries doc/*Obj*.3. + + 2. Namespaces. There is a new namespace mechanism based on the + namespace implementation by Michael McLennan of Lucent Technologies. + This includes new "namespace" and "variable" commands. There are + many new C APIs associated with namespaces, but they will not be + exported until Tcl 8.1. Note: the syntax of the namespace command + has been changed slightly since the b1 release. See the changes + file for details. + + 3. Binary I/O. The new object system in Tcl 8.0 supports binary + strings (internally, strings are counted in addition to being null + terminated). There is a new "binary" command for inserting and + extracting data to/from binary strings. Commands such as "puts", + "gets", and "read" commands now operate correctly on binary data. + There is a new variable tcl_platform(byteOrder) to identify the + native byte order for the current host. + + 4. Random numbers. The "expr" command now contains a random number + generator, which can be accessed via the "rand()" and "srand()" math + functions. + + 5. Safe-Tcl enhancements. There is a new "hidden command" + mechanism, implemented with the Tcl commands "interp hide", "interp + expose", "interp invokehidden", and "interp hidden" and the C APIs + Tcl_HideCommand and Tcl_ExposeCommand. There is now support for + safe packages and extension loading, including new library + procedures such as safe::interpCreate (see the manual entry safe.n + for details). + + 6. There is a new package "registry" available under Windows for + accessing the Windows registry. + + 7. There is a new command "file attributes" for getting and setting + things like permissions and owner. There is also a new command + "file nativename" for getting back the platform-specific name for a + particular file. + + 8. There is a new "fcopy" command to copy data between channels. + This replaces and improves upon the not-so-secret unsupported old + command "unsupported0". + + 9. There is a new package "http" for doing GET, POST, and HEAD + requests via the HTTP/1.0 protocol. See the manual entry http.n + for details. + + 10. There are new library procedures for finding word breaks in + strings. See the manual entry library.n for details. + + 11. There are new C APIs Tcl_Finalize (for cleaning up before + unloading the Tcl DLL) and Tcl_Ungets for pushing bytes back into a + channel's input buffer. + + 12. Tcl now supports serial I/O devices on Windows and Unix, with a + new fconfigure -mode option. The Windows driver does not yet + support event-driven I/O. + + 13. The lsort command has new options -dictionary and -index. The + -index option allows for very rapid sorting based on an element + of a list. + + 14. The event notifier has been completely rewritten (again). It + should now allow Tcl to use an external event loop (like Motif's) + when it is embedded in other applications. No script-level + interfaces have changed, but many of the C APIs have. + +Tcl 8.0 introduces the following incompatibilities that may affect Tcl +scripts that worked under Tcl 7.6 and earlier releases: + + 1. Variable and command names may not include the character sequence + "::" anymore: this sequence is now used as a namespace separator. + + 2. The semantics of some Tcl commands have been changed slightly to + maximize performance under the compiler. These incompatibilities + are documented on the Web so that we can keep the list up-to-date. + See the URL http://www.sunlabs.com/research/tcl/compiler.html. + + 3. 2-digit years are now parsed differently by the "clock" command + to handle year 2000 issues better (years 00-38 are treated as + 2000-2038 instead of 1900-1938). + + 4. The old Macintosh commands "cp", "mkdir", "mv", "rm", and "rmdir" + are no longer supported; all of these features are now available on + all platforms via the "file" command. + + 5. The variable tcl_precision is now shared between interpreters + and defaults to 12 digits instead of 6; safe interpreters cannot + modify tcl_precision. The new object system in Tcl 8.0 causes + floating-to-string conversions (and the associated rounding) to + occur much less often than in Tcl 7.6, which can sometimes cause + behavioral changes. + + 6. The C APIs associated with the notifier have changed substantially. + + 7. The procedures Tcl_CreateModalTimeout and Tcl_DeleteModalTimeout + have been removed. + + 8. Tcl_CreateFileHandler and Tcl_DeleteFileHandler now take Unix + fd's and are only supported on the Unix platform + + 9. The C APIs for creating channel drivers have changed as part of + the new notifier implementation. The Tcl_File interfaces have been + removed. Tcl_GetChannelFile has been replaced with + Tcl_GetChannelHandle. Tcl_MakeFileChannel now takes a platform- + specific file handle. Tcl_DriverGetOptionProc procedures now take + an additional interp argument. + +5. Tcl newsgroup +----------------- + +There is a network news group "comp.lang.tcl" intended for the exchange +of information about Tcl, Tk, and related applications. Feel free to use +the newsgroup both for general information questions and for bug reports. +We read the newsgroup and will attempt to fix bugs and problems reported +to it. + +When using comp.lang.tcl, please be sure that your e-mail return address +is correctly set in your postings. This allows people to respond directly +to you, rather than the entire newsgroup, for answers that are not of +general interest. A bad e-mail return address may prevent you from +getting answers to your questions. You may have to reconfigure your news +reading software to ensure that it is supplying valid e-mail addresses. + +6. Tcl contributed archive +-------------------------- + +Many people have created exciting packages and applications based on Tcl +and/or Tk and made them freely available to the Tcl community. An archive +of these contributions is kept on the machine ftp.neosoft.com. You +can access the archive using anonymous FTP; the Tcl contributed archive is +in the directory "/pub/tcl". The archive also contains several FAQ +("frequently asked questions") documents that provide solutions to problems +that are commonly encountered by TCL newcomers. + +7. Mailing lists +---------------- + +A couple of Mailing List have been set up to discuss Macintosh or +Windows related Tcl issues. In order to use these Mailing Lists you +must have access to the internet. If you have access to the WWW the +home pages for these mailing lists are located at the following URLs: + + http://www.sunlabs.com/research/tcl/lists/mactcl-list.html + + -and- + + http://www.sunlabs.com/research/tcl/lists/wintcl-list.html + +The home pages contain information about the lists and an HTML archive +of all the past messages on the list. To subscribe send a message to: + + listserv@sunlabs.sun.com + +In the body of the message (the subject will be ignored) put: + + subscribe mactcl Joe Blow + +Replacing Joe Blow with your real name, of course. (Use wintcl +instead of mactcl if your interested in the Windows list.) If you +would just like to receive more information about the list without +subscribing put the line: + + information mactcl + +in the body instead (or wintcl). + +8. Support and bug fixes +------------------------ + +We're very interested in receiving bug reports and suggestions for +improvements. We prefer that you send this information to the +comp.lang.tcl newsgroup rather than to any of us at Sun. We'll see +anything on comp.lang.tcl, and in addition someone else who reads +comp.lang.tcl may be able to offer a solution. The normal turn-around +time for bugs is 3-6 weeks. Enhancements may take longer and may not +happen at all unless there is widespread support for them (we're +trying to slow the rate at which Tcl turns into a kitchen sink). It's +very difficult to make incompatible changes to Tcl at this point, due +to the size of the installed base. + +When reporting bugs, please provide a short tclsh script that we can +use to reproduce the bug. Make sure that the script runs with a +bare-bones tclsh and doesn't depend on any extensions or other +programs, particularly those that exist only at your site. Also, +please include three additional pieces of information with the +script: + (a) how do we use the script to make the problem happen (e.g. + what things do we click on, in what order)? + (b) what happens when you do these things (presumably this is + undesirable)? + (c) what did you expect to happen instead? + +The Tcl community is too large for us to provide much individual +support for users. If you need help we suggest that you post questions +to comp.lang.tcl. We read the newsgroup and will attempt to answer +esoteric questions for which no-one else is likely to know the answer. +In addition, Tcl support and training are available commercially from +NeoSoft (info@neosoft.com), Computerized Processes Unlimited +(gwl@cpu.com), and Data Kinetics (education@dkl.com). + +9. Tcl version numbers +---------------------- + +Each Tcl release is identified by two numbers separated by a dot, e.g. +6.7 or 7.0. If a new release contains changes that are likely to break +existing C code or Tcl scripts then the major release number increments +and the minor number resets to zero: 6.0, 7.0, etc. If a new release +contains only bug fixes and compatible changes, then the minor number +increments without changing the major number, e.g. 7.1, 7.2, etc. If +you have C code or Tcl scripts that work with release X.Y, then they +should also work with any release X.Z as long as Z > Y. + +Alpha and beta releases have an additional suffix of the form a2 or b1. +For example, Tcl 7.0b1 is the first beta release of Tcl version 7.0, +Tcl 7.0b2 is the second beta release, and so on. A beta release is an +initial version of a new release, used to fix bugs and bad features before +declaring the release stable. An alpha release is like a beta release, +except it's likely to need even more work before it's "ready for prime +time". New releases are normally preceded by one or more alpha and beta +releases. We hope that lots of people will try out the alpha and beta +releases and report problems. We'll make new alpha/beta releases to fix +the problems, until eventually there is a beta release that appears to +be stable. Once this occurs we'll make the final release. + +We can't promise to maintain compatibility among alpha and beta releases. +For example, release 7.1b2 may not be backward compatible with 7.1b1, even +though the final 7.1 release will be backward compatible with 7.0. This +allows us to change new features as we find problems during beta testing. +We'll try to minimize incompatibilities between beta releases, but if +a major problem turns up then we'll fix it even if it introduces an +incompatibility. Once the official release is made then there won't +be any more incompatibilities until the next release with a new major +version number. + +Patch releases have a suffix such as p1 or p2. These releases contain +bug fixes only. A patch release (e.g Tcl 7.6p2) should be completely +compatible with the base release from which it is derived (e.g. Tcl +7.6), and you should normally use the highest available patch release. |