Tcl by John Ousterhout University of California at Berkeley ouster@cs.berkeley.edu 1. Introduction --------------- This directory contains the sources and documentation for Tcl, an embeddable tool command language. The information here corresponds to release 6.7. For an introduction to the facilities provided by Tcl, your best bet is to retrieve the partial draft of the Tcl/Tk book, which is available for FTP from the standard Tcl/Tk release directories. Another possibility is to see the paper ``Tcl: An Embeddable Command Language'', in the Proceedings of the 1990 Winter USENIX Conference. A copy of that paper is also available in Postscript form in the distribution directory. However, the paper corresponds to a much earlier version of Tcl (approximately version 3.0), so some details of the paper may not be correct anymore and there are many new features not described in the paper. 2. What's New Or Different In This Release ------------------------------------------ Tcl 6.7 contains just a few changes to fix a few minor configuration and installation problems with Tcl 6.6. The 6.6 release also contains only minor changes and should not break any existing Tcl scripts or C programs. Refer to the "changes" file for complete details on all the changes. Below is a list of the most significant changes in the 6.6 release: (a) Added "elseif" support to the "if" command. (b) Changed "puts" and "read" to support initial "-nonewline" switch instead of additional "nonewline" argument. The old form is still accepted but it's obsolete and shouldn't be used any more. Puts now allows the file argument to be omitted, in which case it defaults to stdout. (c) Fixed several bugs in 6.5 related to detecting the ends of long commands. (d) Improved the Makefile (eliminated -f switch to cp, improved installation, etc.) Here are a few of the most important changes that appeared in the earlier 6.5 release. As with 6.6 and 6.7, the 6.5 release should not break any existing Tcl scripts or C programs. (a) The "unknown" procedure has been improved in several ways: - It now allows nested auto-loads, so that the auto-load of one file can trigger additional auto-loads, as long as there are no cycles. - It now emulates csh's "!!", "!<num>", and "^<old>^<new>" history substitutions. - Auto_reset now deletes all auto-loaded procedures so that they'll be reloaded from disk the next time they're invoked. This makes script debugging easier. (b) The installation setup has been modified (improved?) in several ways: - The Makefile checks to be sure that config has been run and won't compile the program if it hasn't. - The TCL_LIBRARY environment variable can be used to override the compiled-in location of the library directory. - The "config" script is now cleverer about figuring out which switches to pass to nm. - Manual entries have been renamed to use ".3" and ".n" extensions. - The Makefile includes a "make install" target. - Introductory documents are no longer part of the release; they have to be retrieved separately. (c) There's a new command, "info complete", plus a C procedure Tcl_CommandComplete, which provide some help in parsing Tcl commands. 3. Documentation ---------------- The "doc" subdirectory contains a complete set of manual entries for Tcl. Files with extension ".3" are for C library procedures provided by Tcl; files with extension ".n" describe the core Tcl commands. The file "doc/Tcl.n" gives an overall description of the Tcl language and describes the core Tcl commands (most of this material is now available in a more palatable form in the book draft). 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 <file> where <file> is the name of the man page you'd like to print. 4. Machines supported --------------------- If you follow the directions below, this release should compile and run on the following configurations either "out of the box" or with only trivial changes: - Sun-3's, Sun-4's, SPARCstation-1's and SPARCstation-2's running many variants of SunOS, such as 4.1. - DECstation-3100's and DECstation-5000's running many versions of Ultrix, such as 2.0 and 4.2. - DEC VAXes running many versions of Ultrix or BSD UNIX. - Intel 386 based systems running SCO Unix 3.2v2. - Intel 386 based systems running SCO Xenix 2.3.3. - Intel 386 based systems running Bell-Tech (now Intel) Unix 3.2.0. - Silicon Graphics systems running IRIX 4.0. - Various H-P machines running versions of HP-UX such as 7.05 - Sequent Symmetry running versions of Dynix/ptx such as v1.2.4 - AT&T 368 machines running SVR4 2.0.1 If you find problems running Tcl on any of the above configurations, please let me know. Also, if you are able to compile Tcl and run the test suite successfully on configurations not listed above, please let me know and tell me what changes, if any, you needed to make to do it. I'd like to keep the above list up-to-date and continue to improve the portability of Tcl. Tcl can be used on many other configurations with only a few modifications. The file "porting.notes" contains information sent to me about what it took to get Tcl to run on various other configurations. I make no guarantees that this information is accurate or complete, but you may find it useful. If you get Tcl running on a new configuration, I'd be happy to receive new information to add to "porting.notes". 5. Compiling Tcl ---------------- To compile Tcl on any of the configurations listed above, or systems similar to them, do the following: (a) If your system isn't one of the ones listed above, look in the file "porting.notes" to see if your system is listed there. This file contains additional notes on getting Tcl to run on various other systems. (b) Edit the "set" commands at the beginning of the file "config" if necessary to correspond to your system configuration (they should already be right for most versions of Unix). (c) Configure the Makefile in this directory according to the instructions at the beginning of the file. In particular, if you're not going to install the library in the suggested place (/usr/local/lib/tcl) you need to reset the TCL_LIBRARY variable. You may also want to change CC, CFLAGS, etc. (d) Type "./config" to invoke Tcl's auto-configuration script. This script pokes around in your system to see if certain almost-standard things are missing (header files, library procedures, etc.); if your system doesn't seem to have them, it configures Tcl to use its own copies of these things instead (Tcl's copies are kept in the "compat" subdirectory). Config prints out messages for all the substitutions it made. You can ignore any of the messages unless they say "ERROR!!", in which case something is fundamentally wrong and the script couldn't handle your system configuration. If Tcl isn't able to configure itself to compile on your machine, then I suggest the following approach: - Start again with a fresh copy of the distribution. - Set the #defines that appear at the very front of tclUnix.h (before the first #include) to correspond to your system. - Create a file "configured" in this directory, so that the Makefile won't generate errors. - If things don't compile or don't link, then you may need to copy some of the .c or .h files from the "compat" directory into the main Tcl directory to compensate for files missing from your system. Modify the COMPAT_OBJS definition in Makefile to include a .o name for each of the .c files that you copied up from the compat directory. (e) Type "make" to compile the library. This will create the Tcl library in "libtcl.a". The Makefile should work without any modifications but you may wish to personalize it, e.g. to turn on compiler optimization. (f) Type "make install" to install Tcl binaries and script files in standard places. You'll need write permission on /usr/local to do this. See the Makefile for details on where things get installed. (g) Type "make tclTest", which will create a simple test program that you can use to try out the Tcl facilities. TclTest is just a main-program sandwich around the Tcl library. It reads standard input until it reaches the end of a line where parentheses and backslashes are balanced, then sends everything it's read to the Tcl interpreter. When the Tcl interpreter returns, tclTest prints the return value or error message. TclTest defines a few other additional commands, most notably: echo arg arg ... The "echo" command prints its arguments on standard output, separated by spaces. 6. Test suite ------------- There is a relatively complete test suite for all of the Tcl core in the subdirectory "tests". To use it just type "make test" in this directory. You should then see a printout of the test files processed. If any errors occur, you'll see a much more substantial printout for each error. Tcl should pass the test suite cleanly on all of the systems listed in Section 4. See the README file in the "tests" directory for more information on the test suite. 7. Compiling on non-UNIX systems -------------------------------- The Tcl features that depend on system calls peculiar to UNIX (stat, fork, exec, times, etc.) are now separate from the main body of Tcl, which only requires a few generic library procedures such as malloc and strcpy. Thus it should be relatively easy to compile Tcl for these machines, although a number of UNIX-specific commands will be absent (e.g. exec, time, and glob). See the comments at the top of Makefile for information on how to compile without the UNIX features. 8. Special thanks ----------------- Mark Diekhans and Karl Lehenbauer of Santa Cruz Operation deserve special thanks for all their help during the development of Tcl 6.0. Many of the new features in Tcl 6.0 were inspired by an enhanced version of Tcl 3.3 called Extended Tcl 4.0, which was created by Mark, Karl, and Peter da Silva. Mark and Karl explained these features to me and provided excellent (and challenging) feedback during the 6.0 development process. They were also a great help in finding and fixing portability problems. Without their ideas and assistance Tcl 6.0 would be much less powerful. 9. Support ---------- There is no official support organization for Tcl, and I can't promise to provide much hand-holding to people learning Tcl. However, I'm very interested in receiving bug reports and suggestions for improvements. Bugs usually get fixed quickly (particularly if they are serious), but enhancements may take a while and may not happen at all unless there is widespread support for them. 10. 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 this newsgroup both for general information questions and for bug reports. I read the newsgroup and will attempt to fix bugs and problems reported to it.
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