14 ms·

Who Says Tcl Rules?

160 points by blacksqr 7y ago

Zenst 7y ago
TCL was/is a wonderful glue language and by that I mean it is great for connecting diverse things together. Company I worked at in the late 90's, used to to control a few hundred modems hanging some RS/6000's taking customer terminal orders. This was all handled by TCL and even had a lovely X11 control interface thanks to TK. These then got sent upto the mainfrom for processing. Was also used to provide an assured file transfer to an AS/400 over FTP. At the time you had shell, peal, or was looking at C and the likes of java still being defined and in need of optimisation (saw some nice stuff in java, but would need 10x resources to run compared to alternatives, moore's law helped that within a few years afterwards). But it was robust and great at interacting with whatever you wanted and enabling you to do it in a controlled way. It reminds me how it is perceived in much the same way AWK was and still is, it's a hidden gem that many never bothered with but if you spend a bit of time to learn it, you start to think, why didn't I look into this more earlier. Though python has in so many ways, usurped it and indeed AWK for their niche uses, they still have their places. [EDIT X11, not Z11 typo]
- AlexMax 7y ago
  > Though python has in so many ways, usurped it Funny you should mention that. Python's standard GUI system is still based on tk, and from a quick look at the docs you can even run a tcl script from inside Python. https://docs.python.org/3/library/tkinter.html https://docs.python.org/3/library/tkinter.html
  - deleted 7y ago
    [deleted]
- tyingq 7y ago
  You mentioned AWK. I'm somewhat surprised the C extension capability of gawk never took off. AWK could have competed with Perl in its heyday. There are extensions that add select(), sleep(), sockets, serialization, xmllib, and other C ABI based stuff that helped Perl. Too little, too late, I guess.
PaulHoule 7y ago
Tcl is very similar to LISP where the "list" is a delimiter-separated string instead of the car-cdr thing. It's a clever language but it has the kind of sloppiness that Python has for better and for worse. In particular (in both languages) you can look up the stack and see and influence more than most people think you should. I've come to appreciate the module system in Javascript which is static enough to allow tree shaking. You could not do that reliably for Tcl or Python -- you can't even do it in Java because almost all Java code does something with passing strings to the Classloader, even if it is just the standard library looking things up in resource files. Many people who like Tcl have moved on to Lua for various reasons.
ainar-g 7y ago
I wrote one of my term papers in Tcl/Tk back in the days. It was a version of the Towers of Hanoi, IIRC. Still the best desktop UI programming experience of my life (although arguably I haven't had a lot since then). Tcl is a very nice language for small scripts. Kind of like a LISP for mere mortals. By the way, does anybody know if anyone ever attempted to add a kind of static typing to Tcl? It would be very interesting to see how a stringly-typed language would go about that.
pjmlp 7y ago
I enjoyed using it back in the .com days for our own AOL Server like app server, at the startup I was working on. Nowadays not sure if it still has viable market.
- doublerabbit 7y ago
  AOL Server has been replaced with naviserver. Which is just as excellent. I've been creating a webApp in TCL with the help of navi. It's just so simple to get it done. Setup a GET method to a TCL procedure and then return the HTML of that procedure.
  - pjmlp 7y ago
    Thanks for the heads up, will have a look at it if nothing else at least for nostalgia. :) I think many TCLers weren't that amazed when Rails showed up.
- commandlinefan 7y ago
  About 20 years or so ago, I was hired at a large online travel site to assist in porting the entire codebase from a mix of TCL and C++ to (then new, popular, exciting) Java. I had a strong background in both C++ and Java at the time but had never even heard of TCL. When I first started looking at some of the code, I could see why it was a natural choice for building websites: the TCL syntax seemed to just flowed naturally into HTML. When I, as the “new Java guy” inevitably got blamed for the shortcomings of Java against the old TCL codebase, I was hard-pressed to defend JSP against it. I never really worked with TCL much, but even 10 years later, long after the migration was complete, the old hands still missed it.
  - davidw 7y ago
    It was a perfect language for the web in a lot of ways. With some other guys, I made an Apache module that let you do PHP type scripts, back in the day: https://tcl.apache.org/rivet/ https://tcl.apache.org/rivet/ For a while, I know that https://flightaware.com/ https://flightaware.com/ used it fairly heavily. Indeed, their careers page still shows an interest in Tcl skills.
doublerabbit 7y ago
I code perl and I code TCL. I like both. Perl has the magic and TCL has the voodoo. Add both together you get voodoo magic which is quite fascinating.
- forinti 7y ago
  The thing I like the most about Tcl is Tk and Tk works nicely with Perl. I've used Tcl in various cases in which I needed to provide the client with and executable. Freewrap gives you a reasonably sized executable (it's a lot better than having your end-user install Java or even Perl).
  - mst 7y ago
    Note also that while Perl's Tk.pm is based on an ancient fork of Tk, if you use Tcl.pm + Tkx.pm then perl embeds your "real" Tcl/Tk and talks to that so you get properly modern functionality. This is how the tkdocs.com examples in Perl maintain parity.
mhd 7y ago
I think it's interesting to look at Tcl's pedigree and compare it with Perl. Both definitely have a strong Unix heritage. Perl's initial use case was scripting where you went beyond both awk and the shell, and regarding syntax stuck to the former. The target audience certainly was supposed to know a bit about programming, but shouldn't Tcl on the other hand is more shell-like in its core syntax, trying to simplify that. Not really because it's supposed to supplant shell scripts, but because it has a similar target audience, people looking to automate things (or customize them). At least that's the beginning, and if it would've stayed that way, nobody would lament either language's passing, as they'd be good in their niche. To truly fall, one must rise first. Perl did that with early web programming (CGI), Tcl with UI programming. I like both a lot. I've had a lot of fun programming with Tcl, and it was interesting how your workflow changes if a UI is really, really close to hand (sorry, TKinter doesn't come close to me, the only other language I'd nominate for that would be Rebol). Programming with BASIC I always asked for input, programming with Perl/Python I always pass command line parameters, with Tcl I often popped up small Windows.
- smacktoward 7y ago
  There was a period in the early-Web days when Tcl looked like a serious contender to take the lead in Web programming too, thanks to its use as the main scripting language in the influential AOLServer (see https://en.wikipedia.org/wiki/AOLserver https://en.wikipedia.org/wiki/AOLserver). Of course that didn't end up happening, but it's interesting to think about what might have been different if it had.
  - bch 7y ago
    It was also embedded in browsers[0]. It “could have been javascript”. Sort of a bitter-sweet scenario - I think some were excited that Tcl could have been out there more, in people’s face, but others think Tcl dodged a bullet, as mass adoption would have laid a tough burden of backward compatibility and a bit of ossification that the core team is happy to not have mandated on them. [0] https://books.google.ca/books?id=GQIMAgAAQBAJ&pg=PA4&lpg=PA4&dq=%22tcl%22+web+browser+ncsa&source=bl&ots=P7j7qSO1FQ&sig=ACfU3U0mC1wybigQnPqzpl_FOByVZecLEw&hl=en&sa=X&ved=2ahUKEwi_lrbWyarnAhVaHDQIHQmYDGEQ6AEwAHoECAQQAQ#v=onepage&q=%22tcl%22%20web%20browser%20ncsa&f=false https://books.google.ca/books?id=GQIMAgAAQBAJ&pg=PA4&lpg=PA4...
gugagore 7y ago
If I understood correctly, Tcl's metaprogramming capabilities are based on manipulating strings and not a syntax tree (e.g. lisp). Is that a key component of making it usable by "mere mortals"? I think ideally I'd like both capabilities, which seems possible if you just expose the language's parser as a function.
- kragen 7y ago
  Yes. And Tcl does expose list-parsing functions, so you can pretend the strings are lists. Also, current versions of Tcl have optimizations around that.
- mst 7y ago
  Tcl's syntax is sufficiently simple that you can write something that parses it in Tcl, and there's examples of doing that to do more complex metaprogramming all over the wiki. Plus things like uplevel let you jam a lot of meta trickery into commands without needing AST manipulation. So, yeah, you do get both capabilities, it's just done atop the very simple baseline system, if that makes sense. (look at e.g. 'snit', a pure Tcl OO system, as an example of what can be done with just Tcl itself)
- geoelectric 7y ago
  The other comment mentions it in passing, but the ability to uplevel (operate within the scope of your caller instead of your own) means the difference between statements and function calls is blurred. That, along with the ability to pass code block literals, lets you redefine the language into your own DSL with new control flow statements. You can define a “while loop” function, for example. Before heavy use of closures and callbacks in dynamic languages (Array.forEach, for example) became the thing this was pretty huge, and it’s still nicer syntax sugar than you get defining control structures with that route. I used TCL with Squish for Qt-based UI test automation for a couple of years. For stuff like that where you really do want a set of domain-specific imperatives you can string together, it was really cool to work with. Biggest downside was you could get too fancy and find yourself alone off in the weeds of your own DSL.
- lmm 7y ago
  I think the keys are a) uplevel (which might be very difficult to do in a compilable language?) and b) having a syntax that's a bit more traditional. It's not the fact that you're manipulating strings - indeed I'd very much like a TCL that allowed you to metaprogram with a more structured representation.
rakoo 7y ago
A longer love letter from antirez (Salvatore Sanfilippo) to TCL: http://antirez.com/articoli/tclmisunderstood.html http://antirez.com/articoli/tclmisunderstood.html
nicbarth 7y ago
Aha Tcl/Tk makes writing desktop apps fun! In my system admin days I used it for little UI's to interface with my bash scripts. Running scripts or little visualization tools on remote servers with X forwarding was pretty nifty too!
yesenadam 7y ago
A few years ago I installed XCode on my Mac, started learning it (looked 1000x more complicated than my previous IDE.."Hello world" auto-creates dozens of files and folders..) and read hundreds of pages of docs, started learning Objective-C, to try to draw pixels on the screen. Found out that was impossible! Ok, so basic graphics. Shapes.. I never bothered doing much at all. Too much hassle. Discovered Tcl/Tk a lil while later. They were already on my Mac. With a half-dozen-line program in 1 minute I'd made a window on my screen with text. Graphics not much harder. I couldn't believe I'd gone through all that! haha. Had no idea GUIs could be so simple to write on a Mac. Noone told me. I wrote a couple of games in a few days. Tcl is a kinda weird language, unique, but very easy to get the hang of and be very productive in, a joy. I loved it.
- bachmeier 7y ago
  This is all true. Tk is a great way to make a GUI on Mac or Windows. Linux, not so much, as it's so ugly and outdated that it's basically unusable. Maybe things have changed in recent years, but a 1995-style GUI just doesn't cut it.
  - davidw 7y ago
    It's not that hard to give it some styling to make it look modern-ish enough to get things done with it.
  - bluedays 7y ago
    The tk framework has had some improvements in 8.5 when ttk was added that modernize the framework. You can make really attractive Windows now with ttk on Linux now that wasn’t possible before.
    - acqq 7y ago
      Exactly, Tk looks good on all platforms at latest since 8.5 and the new engine. The relevant tutorial: https://tkdocs.com/tutorial/intro.html https://tkdocs.com/tutorial/intro.html Which exists since 2008. Here's the minimal example for Tcl, Perl, Python and Ruby (note -- Tk doesn't have to be used only in Tcl!) with the pictures of the native looking interfaces on Mac OS X, Windows and Linux (all three): https://tkdocs.com/tutorial/firstexample.html https://tkdocs.com/tutorial/firstexample.html
stkni 7y ago
My first experience of Tcl/Tk was circa 2000. The finance house I worked at had used it to implement a real-time order management system. Even better was the ability to attach to the running ui or server (yes we had both), replace some of the code on-the-fly, and disconnect. Perhaps not so amazing these days, but it was way ahead of anything else I'd seen upto that point and pretty mind-bending for a C/C++ coder.
kragen 7y ago
The best hagiography of St. Tcl is by Yosef Kreinin: https://yosefk.com/blog/i-cant-believe-im-praising-tcl.html https://yosefk.com/blog/i-cant-believe-im-praising-tcl.html I wowed some students in my operations research class a couple of months ago by writing a few lines of code in the Python interpreter and popping up a window with a button in it with Tkinter. "You keep doing magic!"
- braythwayt 7y ago
  I recall Philip Greenspun’s (of the “tenth rule” fame) book about web development. In it, he explained how he was G$D with TCL and AOLServer while others around him were still arguing about how high to pile the Java towers of abstraction. http://philip.greenspun.com/panda/ http://philip.greenspun.com/panda/
  - yesenadam 7y ago
    That link is to Philip and Alex's Guide to Web Publishing. I'd looked at a lot of pages on that site before a while ago, but didn't read that book, thinking maybe it's out of date and not worth reading. Boy I was wrong, it's gold. Looking at it just now, I couldn't help thinking his style of illustrating with photos was an influence on your own books?! I guess so. (I've only read the 2 coffee-themed JS books, which I really loved. Thank you! p.s. The most sophisticated JS program I wrote was "JavaScript REPL with allong.es" hehe.)
  - dublin 7y ago
    I haven't looked in ages - is AOLserver still the best Tcl web-app platform? Tcl is an amazingly direct programming language, which makes things easy to do, and with the significant advantage of crystal-clear readability, and less error-prone code. (A friend of mine maintains Tcl is really short for "try coding less"...)
typon 7y ago
Tcl is single handedly responsible for billions of dollars of damage in the EDA industry
- gugagore 7y ago
  I wonder if you mean Tcl is bad, or that the damage is caused by Tcl being powerful and obviating the need for version upgrades of special-purpose software. Or something else.
  - PhaseLockk 7y ago
    I'm not that guy, but here's my interpretation: tcl is used as the embedded scripting language in the vast majority of EDA tools. In some ways it performs this job quite well, with tool companies providing functions which parse their arguments like inputs to a shell script. For example, you can call report_timing -from ... -to ... When the commands have 50 optional parameters, this method of calling is convenient. However, the problem is that it has been pushed to its absolute limit. Massive automated design flows consisting of tens to hundreds of thousands of lines of often highly unstructured tcl are present at most semiconductor companies. All of this code is written by VLSI engineers who have not much software training. These engineers take advantage of the highly dynamic nature of tcl to solve their problems quickly... and the result is often an unmaintainable mess of code. As an example, I've almost never seen anyone use tcls module system, instead its just scripts using the `source` function to load other scripts. Since the language is not mainstream among software engineers, there is very little material on best practices, and semiconductor companies are extremely locked down meaning there is no open source tooling to speak of. So VLSI engineers continue producing spaghetti code to handle all of the implementation. Obviously I am speaking in very broad strokes, so there may be companies out there that do it right.
  - seabird 7y ago
    Tcl itself isn't really the problem. EDA tooling is generally a dumpster fire (queue horror stories about checking bitstream files into VCS because there's no guarantee the compiler will ever spit the same one out again, even if nothing changed), and Tcl is used to make patchwork fixes to glaring tooling issues. This is all fine and good, but when a vendor can no longer change or fix tooling without running the risk of breaking a large customer's Tcl abomination, the flexibility that it provided is now a problem that's dragging everybody down with it. All of this goes without mentioning that electrical engineers that often get saddled with this aren't very good programmers. People are excited about SymbiFlow for a reason. The hype in spite of how unlikely it is that it will ever match vendor tooling is a testament to the situation.
ohithereyou 7y ago
It's amusing to see Mike Doyle, founder of noted patent troll Eolas[0] being cited on this page. [0] https://en.m.wikipedia.org/wiki/Eolas https://en.m.wikipedia.org/wiki/Eolas
bitwize 7y ago
I still don't know of a faster way to go from zero to functional GUI than to use Tcl/Tk. Not Visual Basic (too much rat wrestling). Certainly not JavaScript with a browser, which requires either authoring considerable HTML alongside your code, using a heavyweight framework, or both (React!). With Tcl/Tk you just write a few lines to throw some controls up and wire them to send appropriate commands to your back end. It's amazing.
- sea6ear 7y ago
  Tcl/Tk was my first love in programming. I've spent years wishing that i could find other environments as easy and capable as Tcl. The only other GUI development environment I've come across that I've found to be similarly easy to develop in (and cross-platform) is Free Pascal / Lazarus. I assume the commercial Delphi offerings might be similar, but I don't have any experience with them.
- 7thaccount 7y ago
  Rebol's View DSL has similar power to TCL/Tk. You can write all sorts of apps in only a few lines of code.
  - 9214 7y ago
    View is not a DSL, it's a graphical engine (based on Anti-Grain Geometry in case of Rebol and native in case of Red). What you are talking about is a combination of View and VID (Visual Interface Dialect).
    - 7thaccount 7y ago
      Sorry you're right and thanks for correcting my error. I guess I was just trying to say Rebol/Red have something similar to TCL/Tk in that you can trivially build powerful GUIs.
tus88 7y ago
If they exist, you are guaranteed to find them on HN.
nobleach 7y ago
My immediate answer to this question is/was, "The Samba team!". Messing around with Samba 3 beta and OpenLDAP back in the day was the reason I bought and read "Sams Teach Yourself TCL/Tk". I really enjoyed how easy it was to get results. All of my GUI programming until that point had been Borland Delphi and Visual Basic. So this felt so fresh and close to the metal. (No dragging and dropping and having 300 lines of code being generated behind the scenes) I have no idea when or why I stopped playing with it.
ghettoimp 7y ago
Not to be mean about it or anything, but I really dislike TCL. Granted, you could do much worse. Unlike shell scripts you at least have access to sensible data structures like lists, dictionaries, and so on. And unlike shell scripts or Makefiles, you can actually handle spaces in your data, so that's at least not horrible. But when everything is a string, there is no type safety anywhere. So many things that should just be compile errors blow up on you at run-time instead. God help you if you're using code that other people are updating and silently changing. The syntax is also pretty annoying at times. For instance, you can use unbalanced {} characters within comments, but not if those comments are within a proc. You can nicely write long lists over many lines with {...}, but you can't put comments in those. Anyway, haters gonna hate. I hope other folks like it more than I do.
- sedatk 7y ago
  Lack of strong-typing isn't something specific to TCL or rare at all. Python and JavaScript are weakly typed too.
  - gugagore 7y ago
    but not everything is a string in Python and JavaScript. It's possible your parent didn't mean literally "strong typing" or even "static typing", but instead more generally "notions of types, whether at runtime or before".
    - ghettoimp 7y ago
      Yes exactly. TCL is somehow even more weakly typed than conventional dynamically typed languages. For instance, in Python, len(3) is an error, but in TCL, llength 3 is 1.
- siver_john 7y ago
  I'm in a similar boat of TCL dislike. But that probably has a lot to do with my first introduction was through installing a program and having all types of difficulties doing so. Being exposed to a language at first by trying to understand what it is doing in installing software is probably not a great introduction. I did get the software installed but my dislike remained This was probably further increased by the fact that post that I had bad experiences with my supervisor that just soured everything about it. Even to this day where it would benefit me to use TCL, I try to avoid it in favor of languages like Python.
deleted 7y ago
[deleted]
topspin 7y ago
So someone cited my HN comment[1] about Tcl from yesterday on this page. That's fine. I recall one issue I had with Tcl was lack of support for monotonic clocks (on Linux anyhow.) So a sleep might take a long time to expire if the system time changed to the past. I wonder if that ever got addressed. [1] https://news.ycombinator.com/reply?id=22174228 https://news.ycombinator.com/reply?id=22174228
- rkeene2 7y ago
  TIP 302 has been open to fix this in Tcl 8.7+, and there is atleast one implementation of the fix. I looked at addressing TIP 302, but it was complicated since Tcl virtualizes the clock (like it does the filesystem).
yesenadam 7y ago
"The programmer is free to reinvent the language, write new control structures, and so on." I don't remember that about Tcl.. How far can you do that? And how do you do that? (an example would be great). Thanks. I've been getting into Forth lately, where you can redefine absolutely everything[0], and make your own anything, to a ridiculous degree. Not sure what this quote means. I'll be pleasantly surprised if it's true. [0] Well, you are stuck with the stack(s) I guess. But that's about it. edit: Thank you all for the great answers!
- davidw 7y ago
  Here's a starting point: https://wiki.tcl-lang.org/page/New+Control+Structures https://wiki.tcl-lang.org/page/New+Control+Structures
  - blacksqr 7y ago
    tl;dr Tcl has an "uplevel" command that lets you execute code in the variable scope level of the procedure that called it. The classic example is a "do" loop, which Tcl doesn't include out of the box: proc do {body condition} { while 1 { uplevel $body if {![uplevel [list expr $condition]]} break } } set i 10 do {puts $i ; incr i -1} {$i > 0} output: 10 9 8 7 6 5 4 3 2 1
- Uhhrrr 7y ago
  It is pretty true. There are not many rules in Tcl. One of them is that the first word is a procedure, and the following words are arguments. Procedures are defined using "proc", which is also a procedure: proc sum {x y} { return [expr $x + $y] } Here proc is taking 3 args: name, args, and body (curly braces wind up enclosing one arg). But you can also redefine proc, using proc. Here is a neat function which uses this to keep other procs from being given new definitions: rename proc _proc _proc proc {name args body} { if {[info commands $name]!=""} { puts stderr "warning: [info script] redefines $name" } _proc $name $args $body } The above is taken from here: https://wiki.tcl-lang.org/page/Guarded+proc https://wiki.tcl-lang.org/page/Guarded+proc List of overloaded procs here: https://wiki.tcl-lang.org/page/Overloading+Proc https://wiki.tcl-lang.org/page/Overloading+Proc
_pmf_ 7y ago
My favorite piece of TCL/Tk code is the official gitk git UI that comes with git and works on Linux and Windows; it's the single file here: https://github.com/git/git/blob/master/gitk-git/gitk https://github.com/git/git/blob/master/gitk-git/gitk
digitalsushi 7y ago
I think it is a testament to just how far good design choices can outweigh the decision of which language. Two lifetimes ago, I worked at a company that sells testing software for CPE devices (consumer grade routers, et cetera). The entire core of that product is written in pure TCL - a fully tunable TCP stack with a knob for adjusting every metric, and a fully state driven architecture composed of TCL primitives that can emulate an entire ISP and a corporate LAN. There are so many languages that would be obvious better choices, but part of what allows a legacy of sledge hammered test cases to evolve is respecting the garden they are grown in - generally when you transplant a tree, you're going to kill it. Instead, a careful analysis of the existing implementation has allowed that product to continue, and grow, for many, many years.
- vosper 7y ago
  > here are so many languages that would be obvious better choices, but part of what allows a legacy of sledge hammered test cases to evolve is respecting the garden they are grown in - generally when you transplant a tree, you're going to kill it. Instead, a careful analysis of the existing implementation has allowed that product to continue, and grow, for many, many years. I love the way you put this. My team is in the middle of an IMO largely pointless port of working code from Scala to JS, because some senior people think Scala is icky... (Even though my team is a JS team, I don't think JS is a better language than Scala. To the objection I get: "we can't find Scala engineers" I point out that JS engineers on my team have had to learn to read Scala in order to port the code, so they're halfway there already...)
  - goatlover 7y ago
    > "we can't find Scala engineers" Is there such a thing as a PL engineer? I thought it was software engineer, and the particular language matters less than general software principles and practices. Plus, any new employee is going to have to learn the code base regardless of whether they start out knowing the language. Any software engineer should be able to learn a new language. The idea that you have to higher engineers who already know the language, particularly a high level general purpose one, seems suspect. It's not like they're writing some low level Rust or C code. It seems like a poor reason to port a code base, but I guess it happens often enough.
silasdb 7y ago
Tcl cross-platform feature is astonishing. With Androwish [1] it steps even further. I have a bunch of private tools for personal organization (time tracker, todo list, notepad-like app) that I've written in Tcl. Over the years, I used Android smartphones more and more and I just wanted all those small apps for Android too, but never had time to learn mobile development. With Androwish I can just run them in my Android almost unmodified! And I can also make use of Android features like notifications. I sync the files between devices with Syncthing [2] or another tool and, voilà! I can use the same apps in both Android and Unix! [1] http://androwish.org/ http://androwish.org/ [2] https://syncthing.net/ https://syncthing.net/ EDIT: syntax
- blacksqr 7y ago
  Some of us would love it if you would share your apps!
  - silasdb 7y ago
    They started as quick-and-dirty apps because I didn't find anything that suited my needs so I decided to write my own. They are still quick-and-dirty (and ugly) but I intend to publish them next months after I clean the code up. Maybe I show them in "Show HN" :-) I still need to discover how I overcome some Androwish limitations. Tk is great but the integration with the system (like copy-n-paste) is still something I need to discover how to deal with.
- znpy 7y ago
  i couldn't find a screenshot, but I would really be curious to see it in action EDIT: found some at http://androwish.org/index.html/wiki?name=Example+Scripts http://androwish.org/index.html/wiki?name=Example+Scripts
- kragen 7y ago
  Oh wow, AndroWish looks amazing! I didn't know about it because it's not on F-Droid. I bet I can run the slide-rule app I wrote in 1997 on my hand computer now!
munk-a 7y ago
This is beside the main point, but my eyes bugged out a bit seeing block-quote style divs (or maybe code style) used to capture the author information but not the quote itself - I suppose someone dumped this into the website from a text file and didn't adjust it for markdown, but it is really bugging me.
Uhhrrr 7y ago
Those first quotes are attributed to "deepchip.com", but that's just the archive of the E-mail Synopsys Users Group (ESNUG). For many years it was the main watering hole for talking about EDA ("electronic design automation" -> hardware design) software. Synopsys was only one of three big EDA companies, but because there were so many tools in the chain, and they were (sometimes) interoperable, all the different products from the different vendors would get discussed, sometimes mercilessly. Someone who wanted to play folk historian could probably have a lot of fun going through the archive, assuming their eyes wouldn't glaze over at terms like "cycle accuracy" or "serial loopback".
matt_the_bass 7y ago
I used Tcl today as part of some Xilinx fpga work. Interesting to learn there is such an ecosystem/community for tcl. I’ll look into adding TK functionality to my Xilinx tools.
agumonkey 7y ago
any good tcl recipe book ? I'm curious on what non trivia tcl code should be organized
- anthk 7y ago
  - TCL TK 8.5 Programming Cookbook - TCL 8.5 Network Programming Yes, we are in 8.6, but except OOP almost nothing changed.
  - agumonkey 7y ago
    Thanks a ton
AceJohnny2 7y ago
One system I work with exposes a CLI. The whole system is written in C, and the CLI is basically just a frontend for a bunch of commands that take in [int argc, char argv]. It is, to misquote Greenspun's tenth, an ad-hoc, informally-specified, bug-ridden, slow implementation of a proper REPL. My secret wish is to replace it with an embedded TCL REPL. TCL isn't perfect, but it's pretty easy to interface with C, and it fits on small targets. My main problem (aside from lack of time) is that I'd actually need a tiny version that would fit within dozens of kilobytes of code. Closest I've found is Jim [1], which is 100-200kB (depending on features). Compare that with Lua, which fits under 100kB (though excluding its standard library). [1] http://jim.tcl.tk/index.html/doc/www/www/index.html http://jim.tcl.tk/index.html/doc/www/www/index.html
- kbr2000 7y ago
  I might have some time this summer, feel free to contact and explain ;)
  - AceJohnny2 7y ago
    I wish I could, but it's all for stupid-secret projects :(
- naasking 7y ago
  > One system I work with exposes a CLI. The whole system is written in C, and the CLI is basically just a frontend for a bunch of commands that take in [int argc, char argv]. It is, to misquote Greenspun's tenth, an ad-hoc, informally-specified, bug-ridden, slow implementation of a proper REPL. Sounds like a poor man's execline: https://skarnet.org/software/execline/ https://skarnet.org/software/execline/
- qznc 7y ago
  Consider these two simplified TCL derivatives: TH1 https://www.fossil-scm.org/xfer/doc/trunk/www/th1.md https://www.fossil-scm.org/xfer/doc/trunk/www/th1.md Picol http://oldblog.antirez.com/post/picol.html http://oldblog.antirez.com/post/picol.html
andoma 7y ago
TCL have an interesting feature where user defined functions (or commands as it's called) can return TCL_RETURN, TCL_BREAK, or TCL_CONTINUE (in addition to TCL_OK and TCL_ERROR as you would expect) which directly affects control flow in the calling functions.
- nrclark 7y ago
  That's some crazy shit right there, thanks for telling us about it! For those interested, here's a link that discusses it: https://www.tcl.tk/man/tcl8.6/TclCmd/return.htm https://www.tcl.tk/man/tcl8.6/TclCmd/return.htm
- lonelappde 7y ago
  Which is a structured form of macros.
yellowapple 7y ago
The only thing stopping me from using Tcl/Tk for literally every desktop application I write is the lack of a good web view (which is unfortunately a hard requirement for a lot of projects nowadays). If I can find (or develop) a WebKit or WebEngine or Gecko or Servo or whatever widget for Tk that actually works reasonably well, then I'd drop Python and Qt5 for that niche in a heartbeat.
- cmacleod4 7y ago
  Take a look at http://www.androwish.org/index.html/wiki?name=jsmpeg+SDL+Video+Driver http://www.androwish.org/index.html/wiki?name=jsmpeg+SDL+Vid... for an experimental approach to displaying Tcl/Tk applications in a web browser.
JohnFen 7y ago
I do! TCL is perhaps my favorite scripting language of all time.
dana321 7y ago
uplevel and upvar.. Kinda strange how scope is restricted to the current level. https://en.wikipedia.org/wiki/Tcl https://en.wikipedia.org/wiki/Tcl
7thaccount 7y ago
I bought Ashok Nadkarni's TCL book recently and TCL has a lot going on in a very small amount of code. It is seriously underrated!
sigzero 7y ago
I love the Tcl language (it's fun). I love the Tcl community as well.
Bendingo 7y ago
No-one yet mentioned expect [0][1], which is the most amazing, general-purpose automation tool I've ever used. IMHO it's creator Don Libes [2] is an original-thinker/innovator in the same league as Ousterhout. [0] https://en.wikipedia.org/wiki/Expect https://en.wikipedia.org/wiki/Expect? [1] https://www.tcl.tk/man/expect5.31/expect.1.html https://www.tcl.tk/man/expect5.31/expect.1.html? [2] https://en.wikipedia.org/wiki/Don_Libes https://en.wikipedia.org/wiki/Don_Libes
DictumMortuum 7y ago
Working in a betting company. The most important applications are still written in TcL. I think it's a lovely language. If it had a debugger it'd be awesome.
- noobdood 7y ago
  Checked ActiveState Tcl? Maybe they have one.
- blacksqr 7y ago
  https://github.com/flightaware/TclProDebug https://github.com/flightaware/TclProDebug
  - DictumMortuum 7y ago
    Thanks! I'll definitely check it out.

160 points by blacksqr 7y ago

TCL was/is a wonderful glue language and by that I mean it is great for connecting diverse things together. Company I worked at in the late 90's, used to to control a few hundred modems hanging some RS/6000's taking customer terminal orders. This was all handled by TCL and even had a lovely X11 control interface thanks to TK. These then got sent upto the mainfrom for processing. Was also used to provide an assured file transfer to an AS/400 over FTP. At the time you had shell, peal, or was looking at C and the likes of java still being defined and in need of optimisation (saw some nice stuff in java, but would need 10x resources to run compared to alternatives, moore's law helped that within a few years afterwards). But it was robust and great at interacting with whatever you wanted and enabling you to do it in a controlled way. It reminds me how it is perceived in much the same way AWK was and still is, it's a hidden gem that many never bothered with but if you spend a bit of time to learn it, you start to think, why didn't I look into this more earlier. Though python has in so many ways, usurped it and indeed AWK for their niche uses, they still have their places. [EDIT X11, not Z11 typo]

AlexMax 7y ago
> Though python has in so many ways, usurped it Funny you should mention that. Python's standard GUI system is still based on tk, and from a quick look at the docs you can even run a tcl script from inside Python. https://docs.python.org/3/library/tkinter.html https://docs.python.org/3/library/tkinter.html
- deleted 7y ago
  [deleted]
tyingq 7y ago
You mentioned AWK. I'm somewhat surprised the C extension capability of gawk never took off. AWK could have competed with Perl in its heyday. There are extensions that add select(), sleep(), sockets, serialization, xmllib, and other C ABI based stuff that helped Perl. Too little, too late, I guess.

PaulHoule 7y ago

Tcl is very similar to LISP where the "list" is a delimiter-separated string instead of the car-cdr thing. It's a clever language but it has the kind of sloppiness that Python has for better and for worse. In particular (in both languages) you can look up the stack and see and influence more than most people think you should. I've come to appreciate the module system in Javascript which is static enough to allow tree shaking. You could not do that reliably for Tcl or Python -- you can't even do it in Java because almost all Java code does something with passing strings to the Classloader, even if it is just the standard library looking things up in resource files. Many people who like Tcl have moved on to Lua for various reasons.

ainar-g 7y ago

I wrote one of my term papers in Tcl/Tk back in the days. It was a version of the Towers of Hanoi, IIRC. Still the best desktop UI programming experience of my life (although arguably I haven't had a lot since then). Tcl is a very nice language for small scripts. Kind of like a LISP for mere mortals. By the way, does anybody know if anyone ever attempted to add a kind of static typing to Tcl? It would be very interesting to see how a stringly-typed language would go about that.

pjmlp 7y ago

I enjoyed using it back in the .com days for our own AOL Server like app server, at the startup I was working on. Nowadays not sure if it still has viable market.

doublerabbit 7y ago
AOL Server has been replaced with naviserver. Which is just as excellent. I've been creating a webApp in TCL with the help of navi. It's just so simple to get it done. Setup a GET method to a TCL procedure and then return the HTML of that procedure.
- pjmlp 7y ago
  Thanks for the heads up, will have a look at it if nothing else at least for nostalgia. :) I think many TCLers weren't that amazed when Rails showed up.
commandlinefan 7y ago
About 20 years or so ago, I was hired at a large online travel site to assist in porting the entire codebase from a mix of TCL and C++ to (then new, popular, exciting) Java. I had a strong background in both C++ and Java at the time but had never even heard of TCL. When I first started looking at some of the code, I could see why it was a natural choice for building websites: the TCL syntax seemed to just flowed naturally into HTML. When I, as the “new Java guy” inevitably got blamed for the shortcomings of Java against the old TCL codebase, I was hard-pressed to defend JSP against it. I never really worked with TCL much, but even 10 years later, long after the migration was complete, the old hands still missed it.
- davidw 7y ago
  It was a perfect language for the web in a lot of ways. With some other guys, I made an Apache module that let you do PHP type scripts, back in the day: https://tcl.apache.org/rivet/ https://tcl.apache.org/rivet/ For a while, I know that https://flightaware.com/ https://flightaware.com/ used it fairly heavily. Indeed, their careers page still shows an interest in Tcl skills.

doublerabbit 7y ago

I code perl and I code TCL. I like both. Perl has the magic and TCL has the voodoo. Add both together you get voodoo magic which is quite fascinating.

forinti 7y ago
The thing I like the most about Tcl is Tk and Tk works nicely with Perl. I've used Tcl in various cases in which I needed to provide the client with and executable. Freewrap gives you a reasonably sized executable (it's a lot better than having your end-user install Java or even Perl).
- mst 7y ago
  Note also that while Perl's Tk.pm is based on an ancient fork of Tk, if you use Tcl.pm + Tkx.pm then perl embeds your "real" Tcl/Tk and talks to that so you get properly modern functionality. This is how the tkdocs.com examples in Perl maintain parity.

mhd 7y ago

I think it's interesting to look at Tcl's pedigree and compare it with Perl. Both definitely have a strong Unix heritage. Perl's initial use case was scripting where you went beyond both awk and the shell, and regarding syntax stuck to the former. The target audience certainly was supposed to know a bit about programming, but shouldn't Tcl on the other hand is more shell-like in its core syntax, trying to simplify that. Not really because it's supposed to supplant shell scripts, but because it has a similar target audience, people looking to automate things (or customize them). At least that's the beginning, and if it would've stayed that way, nobody would lament either language's passing, as they'd be good in their niche. To truly fall, one must rise first. Perl did that with early web programming (CGI), Tcl with UI programming. I like both a lot. I've had a lot of fun programming with Tcl, and it was interesting how your workflow changes if a UI is really, really close to hand (sorry, TKinter doesn't come close to me, the only other language I'd nominate for that would be Rebol). Programming with BASIC I always asked for input, programming with Perl/Python I always pass command line parameters, with Tcl I often popped up small Windows.

smacktoward 7y ago
There was a period in the early-Web days when Tcl looked like a serious contender to take the lead in Web programming too, thanks to its use as the main scripting language in the influential AOLServer (see https://en.wikipedia.org/wiki/AOLserver https://en.wikipedia.org/wiki/AOLserver). Of course that didn't end up happening, but it's interesting to think about what might have been different if it had.
- bch 7y ago
  It was also embedded in browsers[0]. It “could have been javascript”. Sort of a bitter-sweet scenario - I think some were excited that Tcl could have been out there more, in people’s face, but others think Tcl dodged a bullet, as mass adoption would have laid a tough burden of backward compatibility and a bit of ossification that the core team is happy to not have mandated on them. [0] https://books.google.ca/books?id=GQIMAgAAQBAJ&pg=PA4&lpg=PA4&dq=%22tcl%22+web+browser+ncsa&source=bl&ots=P7j7qSO1FQ&sig=ACfU3U0mC1wybigQnPqzpl_FOByVZecLEw&hl=en&sa=X&ved=2ahUKEwi_lrbWyarnAhVaHDQIHQmYDGEQ6AEwAHoECAQQAQ#v=onepage&q=%22tcl%22%20web%20browser%20ncsa&f=false https://books.google.ca/books?id=GQIMAgAAQBAJ&pg=PA4&lpg=PA4...

gugagore 7y ago

If I understood correctly, Tcl's metaprogramming capabilities are based on manipulating strings and not a syntax tree (e.g. lisp). Is that a key component of making it usable by "mere mortals"? I think ideally I'd like both capabilities, which seems possible if you just expose the language's parser as a function.

kragen 7y ago
Yes. And Tcl does expose list-parsing functions, so you can pretend the strings are lists. Also, current versions of Tcl have optimizations around that.
mst 7y ago
Tcl's syntax is sufficiently simple that you can write something that parses it in Tcl, and there's examples of doing that to do more complex metaprogramming all over the wiki. Plus things like uplevel let you jam a lot of meta trickery into commands without needing AST manipulation. So, yeah, you do get both capabilities, it's just done atop the very simple baseline system, if that makes sense. (look at e.g. 'snit', a pure Tcl OO system, as an example of what can be done with just Tcl itself)
geoelectric 7y ago
The other comment mentions it in passing, but the ability to uplevel (operate within the scope of your caller instead of your own) means the difference between statements and function calls is blurred. That, along with the ability to pass code block literals, lets you redefine the language into your own DSL with new control flow statements. You can define a “while loop” function, for example. Before heavy use of closures and callbacks in dynamic languages (Array.forEach, for example) became the thing this was pretty huge, and it’s still nicer syntax sugar than you get defining control structures with that route. I used TCL with Squish for Qt-based UI test automation for a couple of years. For stuff like that where you really do want a set of domain-specific imperatives you can string together, it was really cool to work with. Biggest downside was you could get too fancy and find yourself alone off in the weeds of your own DSL.
lmm 7y ago
I think the keys are a) uplevel (which might be very difficult to do in a compilable language?) and b) having a syntax that's a bit more traditional. It's not the fact that you're manipulating strings - indeed I'd very much like a TCL that allowed you to metaprogram with a more structured representation.

rakoo 7y ago

A longer love letter from antirez (Salvatore Sanfilippo) to TCL: http://antirez.com/articoli/tclmisunderstood.html http://antirez.com/articoli/tclmisunderstood.html

nicbarth 7y ago

Aha Tcl/Tk makes writing desktop apps fun! In my system admin days I used it for little UI's to interface with my bash scripts. Running scripts or little visualization tools on remote servers with X forwarding was pretty nifty too!

yesenadam 7y ago

A few years ago I installed XCode on my Mac, started learning it (looked 1000x more complicated than my previous IDE.."Hello world" auto-creates dozens of files and folders..) and read hundreds of pages of docs, started learning Objective-C, to try to draw pixels on the screen. Found out that was impossible! Ok, so basic graphics. Shapes.. I never bothered doing much at all. Too much hassle. Discovered Tcl/Tk a lil while later. They were already on my Mac. With a half-dozen-line program in 1 minute I'd made a window on my screen with text. Graphics not much harder. I couldn't believe I'd gone through all that! haha. Had no idea GUIs could be so simple to write on a Mac. Noone told me. I wrote a couple of games in a few days. Tcl is a kinda weird language, unique, but very easy to get the hang of and be very productive in, a joy. I loved it.

bachmeier 7y ago
This is all true. Tk is a great way to make a GUI on Mac or Windows. Linux, not so much, as it's so ugly and outdated that it's basically unusable. Maybe things have changed in recent years, but a 1995-style GUI just doesn't cut it.
- davidw 7y ago
  It's not that hard to give it some styling to make it look modern-ish enough to get things done with it.
- bluedays 7y ago
  The tk framework has had some improvements in 8.5 when ttk was added that modernize the framework. You can make really attractive Windows now with ttk on Linux now that wasn’t possible before.
  - acqq 7y ago
    Exactly, Tk looks good on all platforms at latest since 8.5 and the new engine. The relevant tutorial: https://tkdocs.com/tutorial/intro.html https://tkdocs.com/tutorial/intro.html Which exists since 2008. Here's the minimal example for Tcl, Perl, Python and Ruby (note -- Tk doesn't have to be used only in Tcl!) with the pictures of the native looking interfaces on Mac OS X, Windows and Linux (all three): https://tkdocs.com/tutorial/firstexample.html https://tkdocs.com/tutorial/firstexample.html

stkni 7y ago

My first experience of Tcl/Tk was circa 2000. The finance house I worked at had used it to implement a real-time order management system. Even better was the ability to attach to the running ui or server (yes we had both), replace some of the code on-the-fly, and disconnect. Perhaps not so amazing these days, but it was way ahead of anything else I'd seen upto that point and pretty mind-bending for a C/C++ coder.

kragen 7y ago

The best hagiography of St. Tcl is by Yosef Kreinin: https://yosefk.com/blog/i-cant-believe-im-praising-tcl.html https://yosefk.com/blog/i-cant-believe-im-praising-tcl.html I wowed some students in my operations research class a couple of months ago by writing a few lines of code in the Python interpreter and popping up a window with a button in it with Tkinter. "You keep doing magic!"

braythwayt 7y ago
I recall Philip Greenspun’s (of the “tenth rule” fame) book about web development. In it, he explained how he was G$D with TCL and AOLServer while others around him were still arguing about how high to pile the Java towers of abstraction. http://philip.greenspun.com/panda/ http://philip.greenspun.com/panda/
- yesenadam 7y ago
  That link is to Philip and Alex's Guide to Web Publishing. I'd looked at a lot of pages on that site before a while ago, but didn't read that book, thinking maybe it's out of date and not worth reading. Boy I was wrong, it's gold. Looking at it just now, I couldn't help thinking his style of illustrating with photos was an influence on your own books?! I guess so. (I've only read the 2 coffee-themed JS books, which I really loved. Thank you! p.s. The most sophisticated JS program I wrote was "JavaScript REPL with allong.es" hehe.)
- dublin 7y ago
  I haven't looked in ages - is AOLserver still the best Tcl web-app platform? Tcl is an amazingly direct programming language, which makes things easy to do, and with the significant advantage of crystal-clear readability, and less error-prone code. (A friend of mine maintains Tcl is really short for "try coding less"...)

typon 7y ago

Tcl is single handedly responsible for billions of dollars of damage in the EDA industry

gugagore 7y ago
I wonder if you mean Tcl is bad, or that the damage is caused by Tcl being powerful and obviating the need for version upgrades of special-purpose software. Or something else.
- PhaseLockk 7y ago
  I'm not that guy, but here's my interpretation: tcl is used as the embedded scripting language in the vast majority of EDA tools. In some ways it performs this job quite well, with tool companies providing functions which parse their arguments like inputs to a shell script. For example, you can call report_timing -from ... -to ... When the commands have 50 optional parameters, this method of calling is convenient. However, the problem is that it has been pushed to its absolute limit. Massive automated design flows consisting of tens to hundreds of thousands of lines of often highly unstructured tcl are present at most semiconductor companies. All of this code is written by VLSI engineers who have not much software training. These engineers take advantage of the highly dynamic nature of tcl to solve their problems quickly... and the result is often an unmaintainable mess of code. As an example, I've almost never seen anyone use tcls module system, instead its just scripts using the `source` function to load other scripts. Since the language is not mainstream among software engineers, there is very little material on best practices, and semiconductor companies are extremely locked down meaning there is no open source tooling to speak of. So VLSI engineers continue producing spaghetti code to handle all of the implementation. Obviously I am speaking in very broad strokes, so there may be companies out there that do it right.
- seabird 7y ago
  Tcl itself isn't really the problem. EDA tooling is generally a dumpster fire (queue horror stories about checking bitstream files into VCS because there's no guarantee the compiler will ever spit the same one out again, even if nothing changed), and Tcl is used to make patchwork fixes to glaring tooling issues. This is all fine and good, but when a vendor can no longer change or fix tooling without running the risk of breaking a large customer's Tcl abomination, the flexibility that it provided is now a problem that's dragging everybody down with it. All of this goes without mentioning that electrical engineers that often get saddled with this aren't very good programmers. People are excited about SymbiFlow for a reason. The hype in spite of how unlikely it is that it will ever match vendor tooling is a testament to the situation.

ohithereyou 7y ago

It's amusing to see Mike Doyle, founder of noted patent troll Eolas[0] being cited on this page. [0] https://en.m.wikipedia.org/wiki/Eolas https://en.m.wikipedia.org/wiki/Eolas

bitwize 7y ago

I still don't know of a faster way to go from zero to functional GUI than to use Tcl/Tk. Not Visual Basic (too much rat wrestling). Certainly not JavaScript with a browser, which requires either authoring considerable HTML alongside your code, using a heavyweight framework, or both (React!). With Tcl/Tk you just write a few lines to throw some controls up and wire them to send appropriate commands to your back end. It's amazing.

sea6ear 7y ago
Tcl/Tk was my first love in programming. I've spent years wishing that i could find other environments as easy and capable as Tcl. The only other GUI development environment I've come across that I've found to be similarly easy to develop in (and cross-platform) is Free Pascal / Lazarus. I assume the commercial Delphi offerings might be similar, but I don't have any experience with them.
7thaccount 7y ago
Rebol's View DSL has similar power to TCL/Tk. You can write all sorts of apps in only a few lines of code.
- 9214 7y ago
  View is not a DSL, it's a graphical engine (based on Anti-Grain Geometry in case of Rebol and native in case of Red). What you are talking about is a combination of View and VID (Visual Interface Dialect).
  - 7thaccount 7y ago
    Sorry you're right and thanks for correcting my error. I guess I was just trying to say Rebol/Red have something similar to TCL/Tk in that you can trivially build powerful GUIs.

tus88 7y ago

If they exist, you are guaranteed to find them on HN.

nobleach 7y ago

My immediate answer to this question is/was, "The Samba team!". Messing around with Samba 3 beta and OpenLDAP back in the day was the reason I bought and read "Sams Teach Yourself TCL/Tk". I really enjoyed how easy it was to get results. All of my GUI programming until that point had been Borland Delphi and Visual Basic. So this felt so fresh and close to the metal. (No dragging and dropping and having 300 lines of code being generated behind the scenes) I have no idea when or why I stopped playing with it.

ghettoimp 7y ago

Not to be mean about it or anything, but I really dislike TCL. Granted, you could do much worse. Unlike shell scripts you at least have access to sensible data structures like lists, dictionaries, and so on. And unlike shell scripts or Makefiles, you can actually handle spaces in your data, so that's at least not horrible. But when everything is a string, there is no type safety anywhere. So many things that should just be compile errors blow up on you at run-time instead. God help you if you're using code that other people are updating and silently changing. The syntax is also pretty annoying at times. For instance, you can use unbalanced {} characters within comments, but not if those comments are within a proc. You can nicely write long lists over many lines with {...}, but you can't put comments in those. Anyway, haters gonna hate. I hope other folks like it more than I do.

sedatk 7y ago
Lack of strong-typing isn't something specific to TCL or rare at all. Python and JavaScript are weakly typed too.
- gugagore 7y ago
  but not everything is a string in Python and JavaScript. It's possible your parent didn't mean literally "strong typing" or even "static typing", but instead more generally "notions of types, whether at runtime or before".
  - ghettoimp 7y ago
    Yes exactly. TCL is somehow even more weakly typed than conventional dynamically typed languages. For instance, in Python, len(3) is an error, but in TCL, llength 3 is 1.
siver_john 7y ago
I'm in a similar boat of TCL dislike. But that probably has a lot to do with my first introduction was through installing a program and having all types of difficulties doing so. Being exposed to a language at first by trying to understand what it is doing in installing software is probably not a great introduction. I did get the software installed but my dislike remained This was probably further increased by the fact that post that I had bad experiences with my supervisor that just soured everything about it. Even to this day where it would benefit me to use TCL, I try to avoid it in favor of languages like Python.

deleted 7y ago

[deleted]

topspin 7y ago

So someone cited my HN comment[1] about Tcl from yesterday on this page. That's fine. I recall one issue I had with Tcl was lack of support for monotonic clocks (on Linux anyhow.) So a sleep might take a long time to expire if the system time changed to the past. I wonder if that ever got addressed. [1] https://news.ycombinator.com/reply?id=22174228 https://news.ycombinator.com/reply?id=22174228

rkeene2 7y ago
TIP 302 has been open to fix this in Tcl 8.7+, and there is atleast one implementation of the fix. I looked at addressing TIP 302, but it was complicated since Tcl virtualizes the clock (like it does the filesystem).

yesenadam 7y ago

"The programmer is free to reinvent the language, write new control structures, and so on." I don't remember that about Tcl.. How far can you do that? And how do you do that? (an example would be great). Thanks. I've been getting into Forth lately, where you can redefine absolutely everything[0], and make your own anything, to a ridiculous degree. Not sure what this quote means. I'll be pleasantly surprised if it's true. [0] Well, you are stuck with the stack(s) I guess. But that's about it. edit: Thank you all for the great answers!

davidw 7y ago
Here's a starting point: https://wiki.tcl-lang.org/page/New+Control+Structures https://wiki.tcl-lang.org/page/New+Control+Structures
- blacksqr 7y ago
  tl;dr Tcl has an "uplevel" command that lets you execute code in the variable scope level of the procedure that called it. The classic example is a "do" loop, which Tcl doesn't include out of the box: proc do {body condition} { while 1 { uplevel $body if {![uplevel [list expr $condition]]} break } } set i 10 do {puts $i ; incr i -1} {$i > 0} output: 10 9 8 7 6 5 4 3 2 1
Uhhrrr 7y ago
It is pretty true. There are not many rules in Tcl. One of them is that the first word is a procedure, and the following words are arguments. Procedures are defined using "proc", which is also a procedure: proc sum {x y} { return [expr $x + $y] } Here proc is taking 3 args: name, args, and body (curly braces wind up enclosing one arg). But you can also redefine proc, using proc. Here is a neat function which uses this to keep other procs from being given new definitions: rename proc _proc _proc proc {name args body} { if {[info commands $name]!=""} { puts stderr "warning: [info script] redefines $name" } _proc $name $args $body } The above is taken from here: https://wiki.tcl-lang.org/page/Guarded+proc https://wiki.tcl-lang.org/page/Guarded+proc List of overloaded procs here: https://wiki.tcl-lang.org/page/Overloading+Proc https://wiki.tcl-lang.org/page/Overloading+Proc

_pmf_ 7y ago

My favorite piece of TCL/Tk code is the official gitk git UI that comes with git and works on Linux and Windows; it's the single file here: https://github.com/git/git/blob/master/gitk-git/gitk https://github.com/git/git/blob/master/gitk-git/gitk

digitalsushi 7y ago

I think it is a testament to just how far good design choices can outweigh the decision of which language. Two lifetimes ago, I worked at a company that sells testing software for CPE devices (consumer grade routers, et cetera). The entire core of that product is written in pure TCL - a fully tunable TCP stack with a knob for adjusting every metric, and a fully state driven architecture composed of TCL primitives that can emulate an entire ISP and a corporate LAN. There are so many languages that would be obvious better choices, but part of what allows a legacy of sledge hammered test cases to evolve is respecting the garden they are grown in - generally when you transplant a tree, you're going to kill it. Instead, a careful analysis of the existing implementation has allowed that product to continue, and grow, for many, many years.

vosper 7y ago
> here are so many languages that would be obvious better choices, but part of what allows a legacy of sledge hammered test cases to evolve is respecting the garden they are grown in - generally when you transplant a tree, you're going to kill it. Instead, a careful analysis of the existing implementation has allowed that product to continue, and grow, for many, many years. I love the way you put this. My team is in the middle of an IMO largely pointless port of working code from Scala to JS, because some senior people think Scala is icky... (Even though my team is a JS team, I don't think JS is a better language than Scala. To the objection I get: "we can't find Scala engineers" I point out that JS engineers on my team have had to learn to read Scala in order to port the code, so they're halfway there already...)
- goatlover 7y ago
  > "we can't find Scala engineers" Is there such a thing as a PL engineer? I thought it was software engineer, and the particular language matters less than general software principles and practices. Plus, any new employee is going to have to learn the code base regardless of whether they start out knowing the language. Any software engineer should be able to learn a new language. The idea that you have to higher engineers who already know the language, particularly a high level general purpose one, seems suspect. It's not like they're writing some low level Rust or C code. It seems like a poor reason to port a code base, but I guess it happens often enough.

silasdb 7y ago

Tcl cross-platform feature is astonishing. With Androwish [1] it steps even further. I have a bunch of private tools for personal organization (time tracker, todo list, notepad-like app) that I've written in Tcl. Over the years, I used Android smartphones more and more and I just wanted all those small apps for Android too, but never had time to learn mobile development. With Androwish I can just run them in my Android almost unmodified! And I can also make use of Android features like notifications. I sync the files between devices with Syncthing [2] or another tool and, voilà! I can use the same apps in both Android and Unix! [1] http://androwish.org/ http://androwish.org/ [2] https://syncthing.net/ https://syncthing.net/ EDIT: syntax

blacksqr 7y ago
Some of us would love it if you would share your apps!
- silasdb 7y ago
  They started as quick-and-dirty apps because I didn't find anything that suited my needs so I decided to write my own. They are still quick-and-dirty (and ugly) but I intend to publish them next months after I clean the code up. Maybe I show them in "Show HN" :-) I still need to discover how I overcome some Androwish limitations. Tk is great but the integration with the system (like copy-n-paste) is still something I need to discover how to deal with.
znpy 7y ago
i couldn't find a screenshot, but I would really be curious to see it in action EDIT: found some at http://androwish.org/index.html/wiki?name=Example+Scripts http://androwish.org/index.html/wiki?name=Example+Scripts
kragen 7y ago
Oh wow, AndroWish looks amazing! I didn't know about it because it's not on F-Droid. I bet I can run the slide-rule app I wrote in 1997 on my hand computer now!

munk-a 7y ago

This is beside the main point, but my eyes bugged out a bit seeing block-quote style divs (or maybe code style) used to capture the author information but not the quote itself - I suppose someone dumped this into the website from a text file and didn't adjust it for markdown, but it is really bugging me.

Uhhrrr 7y ago

Those first quotes are attributed to "deepchip.com", but that's just the archive of the E-mail Synopsys Users Group (ESNUG). For many years it was the main watering hole for talking about EDA ("electronic design automation" -> hardware design) software. Synopsys was only one of three big EDA companies, but because there were so many tools in the chain, and they were (sometimes) interoperable, all the different products from the different vendors would get discussed, sometimes mercilessly. Someone who wanted to play folk historian could probably have a lot of fun going through the archive, assuming their eyes wouldn't glaze over at terms like "cycle accuracy" or "serial loopback".

matt_the_bass 7y ago

I used Tcl today as part of some Xilinx fpga work. Interesting to learn there is such an ecosystem/community for tcl. I’ll look into adding TK functionality to my Xilinx tools.

agumonkey 7y ago

any good tcl recipe book ? I'm curious on what non trivia tcl code should be organized

anthk 7y ago
- TCL TK 8.5 Programming Cookbook - TCL 8.5 Network Programming Yes, we are in 8.6, but except OOP almost nothing changed.
- agumonkey 7y ago
  Thanks a ton

AceJohnny2 7y ago

One system I work with exposes a CLI. The whole system is written in C, and the CLI is basically just a frontend for a bunch of commands that take in [int argc, char argv]. It is, to misquote Greenspun's tenth, an ad-hoc, informally-specified, bug-ridden, slow implementation of a proper REPL. My secret wish is to replace it with an embedded TCL REPL. TCL isn't perfect, but it's pretty easy to interface with C, and it fits on small targets. My main problem (aside from lack of time) is that I'd actually need a tiny version that would fit within dozens of kilobytes of code. Closest I've found is Jim [1], which is 100-200kB (depending on features). Compare that with Lua, which fits under 100kB (though excluding its standard library). [1] http://jim.tcl.tk/index.html/doc/www/www/index.html http://jim.tcl.tk/index.html/doc/www/www/index.html

kbr2000 7y ago
I might have some time this summer, feel free to contact and explain ;)
- AceJohnny2 7y ago
  I wish I could, but it's all for stupid-secret projects :(
naasking 7y ago
> One system I work with exposes a CLI. The whole system is written in C, and the CLI is basically just a frontend for a bunch of commands that take in [int argc, char argv]. It is, to misquote Greenspun's tenth, an ad-hoc, informally-specified, bug-ridden, slow implementation of a proper REPL. Sounds like a poor man's execline: https://skarnet.org/software/execline/ https://skarnet.org/software/execline/
qznc 7y ago
Consider these two simplified TCL derivatives: TH1 https://www.fossil-scm.org/xfer/doc/trunk/www/th1.md https://www.fossil-scm.org/xfer/doc/trunk/www/th1.md Picol http://oldblog.antirez.com/post/picol.html http://oldblog.antirez.com/post/picol.html

andoma 7y ago

TCL have an interesting feature where user defined functions (or commands as it's called) can return TCL_RETURN, TCL_BREAK, or TCL_CONTINUE (in addition to TCL_OK and TCL_ERROR as you would expect) which directly affects control flow in the calling functions.

nrclark 7y ago
That's some crazy shit right there, thanks for telling us about it! For those interested, here's a link that discusses it: https://www.tcl.tk/man/tcl8.6/TclCmd/return.htm https://www.tcl.tk/man/tcl8.6/TclCmd/return.htm
lonelappde 7y ago
Which is a structured form of macros.

yellowapple 7y ago

The only thing stopping me from using Tcl/Tk for literally every desktop application I write is the lack of a good web view (which is unfortunately a hard requirement for a lot of projects nowadays). If I can find (or develop) a WebKit or WebEngine or Gecko or Servo or whatever widget for Tk that actually works reasonably well, then I'd drop Python and Qt5 for that niche in a heartbeat.

cmacleod4 7y ago
Take a look at http://www.androwish.org/index.html/wiki?name=jsmpeg+SDL+Video+Driver http://www.androwish.org/index.html/wiki?name=jsmpeg+SDL+Vid... for an experimental approach to displaying Tcl/Tk applications in a web browser.

JohnFen 7y ago

I do! TCL is perhaps my favorite scripting language of all time.

dana321 7y ago

uplevel and upvar.. Kinda strange how scope is restricted to the current level. https://en.wikipedia.org/wiki/Tcl https://en.wikipedia.org/wiki/Tcl

7thaccount 7y ago

I bought Ashok Nadkarni's TCL book recently and TCL has a lot going on in a very small amount of code. It is seriously underrated!

sigzero 7y ago

I love the Tcl language (it's fun). I love the Tcl community as well.

Bendingo 7y ago

No-one yet mentioned expect [0][1], which is the most amazing, general-purpose automation tool I've ever used. IMHO it's creator Don Libes [2] is an original-thinker/innovator in the same league as Ousterhout. [0] https://en.wikipedia.org/wiki/Expect https://en.wikipedia.org/wiki/Expect? [1] https://www.tcl.tk/man/expect5.31/expect.1.html https://www.tcl.tk/man/expect5.31/expect.1.html? [2] https://en.wikipedia.org/wiki/Don_Libes https://en.wikipedia.org/wiki/Don_Libes

DictumMortuum 7y ago

Working in a betting company. The most important applications are still written in TcL. I think it's a lovely language. If it had a debugger it'd be awesome.

noobdood 7y ago
Checked ActiveState Tcl? Maybe they have one.
blacksqr 7y ago
https://github.com/flightaware/TclProDebug https://github.com/flightaware/TclProDebug
- DictumMortuum 7y ago
  Thanks! I'll definitely check it out.