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On gnu.announce of 9/23, he writes "Why you should not use Tcl". Instead, those wanting to use the Tk tools are commended to a Scheme interpreter with it called STk. Available from: ftp.cs.indiana.edu:pub/scheme-repository/imp/STk-2.1.tar.Z
Below is the post from Rich Stallman "Why you should not use Tcl", and the reply from Ousterhout, which is basically: Why you should not listen to Stallman, in this case. The mentions in the [fantastic] Cyphernomicon of TCL are probably due to my crypto-prototyping project. I did not take the choice lightly when I chose TCL as my "glue" in this project. Two issues that may be interesting but had *little to do* with my decision are (1) language support for big numbers and (2) the TK toolkit (which happens to be in TCL). The reason I chose TCL is that it is designed to work above, underneath, and alongside of C code. TCL has two published interfaces: one is the language and standard commands, and one is a C API for use in combining the language with other C packages. I think of TCL as more of a subroutine library than a language: in the same way that (say) C++ string, file, and dictionary classes can help you be more productive in writing C++ programs, a "little language" interpreter can make you more productive in many kinds of programs. Crypto prototyping systems is one of them. I am not new to LISP or PERL or AWK or POSTSCRIPT or FORTH or SHELL or BASIC or HYPERTALK or various other interpreted langauges. For many differnt projects I would leave TCL for one of them. However when TCL came along, I recognized it as being just the language I had wanted to write myself for doing projects like my current one. Which may say more about what kind of a computer scientist I am that about what lanaguage is best for you in your situation. I'll add that I have a version of my crypto toolkit that is a PERL interpreter, and I've looked briefly at embedding it in PYTHON as well. My problem now is that I need a chunk of time to port it all and package it on sun4 (currently it's on sun3). My problem is not yet that I need more languages to port to. But i'll be glad to have some people help embed these things in all the popular interpreted languages soon. It would be particularly nice to have some people versant with Macs and PCs to package crypto components on those machines -- in applescript or hypercard or visual basic or whatever would help people write crypt code. Below I repost the original articles by Stallman (the spiritual leader of GNU) and Ousterhout (the author of TCL). I'll also point out my greatest respect for both of them, and for their respective projects. They've both made my job as a practicing cypherpunk much easier. Talk about prototyping environments, but please don't spam the list on religious issues. PERL and PYTHON and SCHEME are all pretty good little languages. happy hacking, strick Cypherpunks write Code, but when do they release it? :) [ thanks to iansmith@cc.gatech.edu and boyz@hkn.eecs.berkeley.edu for bringing these articles to my attention. ] - ------- Forwarded Messages Date: Fri, 23 Sep 94 19:14:52 -0400 From: rms@gnu.ai.mit.edu (Richard Stallman) To: gnu@prep.ai.mit.edu Subject: Why you should not use Tcl Newsgroups: gnu.announce,gnu.utils.bug,gnu.misc.discuss,comp.lang.tcl, comp.lang.scheme,comp.windows.x.apps,comp.unix.misc Followup-To: gnu.misc.discuss,comp.lang.tcl,comp.lang.scheme [Please redistribute wherever appropriate.] Why you should not use Tcl Richard Stallman, GNU Project As interest builds in extensible application programs and tools, and some programmers are tempted to use Tcl, we should not forget the lessons learned from the first widely used extensible text editor--Emacs. The principal lesson of Emacs is that a language for extensions should not be a mere "extension language". It should be a real programming language, designed for writing and maintaining substantial programs. Because people will want to do that! Extensions are often large, complex programs in their own right, and the people who write them deserve the same facilities that other programmers rely on. The first Emacs used a string-processing language, TECO, which was inadequate. We made it serve, but it kept getting in our way. It made maintenance harder, and it made extensions harder to write. Later Emacs implementations have used more powerful languages because implementors learned from the problems of the first one. Another lesson from Emacs is that the way to make sure an extension facility is really flexible is to use it to write a large portion of the ordinary released system. If you try to do that with Tcl, you will encounter its limitations. Tcl was not designed to be a serious programming language. It was designed to be a "scripting language", on the assumption that a "scripting language" need not try to be a real programming language. So Tcl doesn't have the capabilities of one. It lacks arrays; it lacks structures from which you can make linked lists. It fakes having numbers, which works, but has to be slow. Tcl is ok for writing small programs, but when you push it beyond that, it becomes insufficient. Tcl has a peculiar syntax that appeals to hackers because of its simplicity. But Tcl syntax seems strange to most users. If Tcl does become the "standard scripting language", users will curse it for years--the way people curse Fortran, MSDOS, Unix shell syntax, and other de facto standards they feel stuck with. For these reasons, the GNU project is not going to use Tcl in GNU software. Instead we want to provide two languages, similar in semantics but with different syntaxes. One will be Lisp-like, and one will have a more traditional algebraic syntax. Both will provide useful data types such as structures and arrays. The former will provide a simple syntax that hackers like; the latter will offer non-hackers a syntax that they are more comfortable with. Some people plan to use Tcl because they want to use Tk. Thankfully, it is possible to use Tk without Tcl. A Scheme interpreter called STk is already available. Please, if you want to use Tk, use it with STk, not with Tcl. One place to get STk is from ftp.cs.indiana.edu:pub/scheme-repository/imp/STk-2.1.tar.Z - ------- Message 2 From: ouster@tcl.eng.sun.com (John Ousterhout) Newsgroups: gnu.misc.discuss,comp.lang.tcl,comp.lang.scheme, comp.unix.misc,comp.windows.x.apps Date: 26 Sep 1994 18:13:27 GMT Organization: Sun Microsystems, Inc. There have been so many follow-ups to Stallman's message that I'm not sure there's any need for me to respond, but I would like to say a few things anyway: First, I'd like to encourage everyone to keep their responses cordial and technical, rather than personal, regardless of how strong your opinions are. Comp.lang.tcl has managed to avoid flame-wars pretty well so far; let's keep it that way by focusing on the technical issues rather than worrying about motives. I think that Stallman's objections to Tcl may stem largely from one aspect of Tcl's design that he either doesn't understand or doesn't agree with. This is the proposition that you should use *two* languages for a large software system: one, such as C or C++, for manipulating the complex internal data structures where performance is key, and another, such as Tcl, for writing small-ish scripts that tie together the C pieces and are used for extensions. For the Tcl scripts, ease of learning, ease of programming and ease of glue-ing are more important than performance or facilities for complex data structures and algorithms. I think these two programming environments are so different that it will be hard for a single language to work well in both. For example, you don't see many people using C (or even Lisp) as a command language, even though both of these languages work well for lower-level programming. Thus I designed Tcl to make it really easy to drop down into C or C++ when you come across tasks that make more sense in a lower-level language. This way Tcl doesn't have to solve all of the world's problems. Stallman appears to prefer an approach where a single language is used for everything, but I don't know of a successful instance of this approach. Even Emacs uses substantial amounts of C internally, no? I didn't design Tcl for building huge programs with 10's or 100's of thousands of lines of Tcl, and I've been pretty surprised that people have used it for huge programs. What's even more surprising to me is that in some cases the resulting applications appear to be manageable. This certainly isn't what I intended the language for, but the results haven't been as bad as I would have guessed. I don't claim that Tcl is without flaws. Some of the flaws, like the lack of a compiler and the lack of module support, will get fixed over time. Others, like the substitution-oriented parser, are inherent in the language. Is it possible to design a language that keeps Tcl's advantages, such as simplicity, easy glue, and easy embedding, but eliminates some of its disadvantages? Almost certainly (there are several decisions that I would re-think if I were starting over). Is the two-language approach really the right one? I still think so, but reasonable people can disagree. Language designers love to argue about why this language or that language *must* be better or worse a priori, but none of these arguments really matter a lot. Ultimately all language issues get settled when users vote with their feet. If Tcl makes people more productive then they will use it; when some other language comes along that is better (or if it is here already), then people will switch to that language. This is The Law, and it is good. The Law says to me that Scheme (or any other Lisp dialect) is probably not the "right" language: too many people have voted with their feet over the last 30 years. I encourage all Tcl dis-believers to produce the "right" language(s), make them publically available, and let them be judged according to The Law. - ------- End of Forwarded Messages -----BEGIN PGP SIGNATURE----- Version: 2.4 iQBVAgUBLpMs6Qq3IMgMJUNlAQGl8gH/WxquXwsd7RbN/Pv8mLwajyZVIN1d53AX TSEtB/grWxbTyUYgPnAu/mzEj33DFPkfttP4/jvdDZir/HsCOxBM5A== =EZgM -----END PGP SIGNATURE-----