Tcl the misunderstood (2006)
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Tcl the misunderstood (2006)
1–10 of 49 posts
Re: Tcl the misunderstood (2006)
#2A really nice article to get one started! thx
Another topic I would like to see introduced in a similarly friendly way is event loops. At my work I am dealing with some Tcl/Tk code that uses event loops and it's a bit of mental gymnastics to get my head around what gets executed when.
Re: Tcl the misunderstood (2006)
#3Back at the beginning of time I worked with Vignette StoryServer, which spun out of aolserver, one of the first "database-backed dynamic website" servers. The scripting language was TCL 7.something.
I never encountered it again, but its elegance always stayed with me. Except for uplevel. Fucking evil.
Re: Tcl the misunderstood (2006)
#4> i18n just happens
No it doesn't... unless machine translation is "there" and built into Tcl.
> Every string is internally encoded in utf-8, all the string operations are Unicode-safe, including the regular expression engine. Basically, in Tcl programs, encodings are not a problem - they just work
Really? Perl's Unicode support is pretty much second-to-none, IME, but you still need to know the encoding of your file handles and so on. Once it knows this, Perl will Just Work(TM). How is this handled in Tcl?
Re: Tcl the misunderstood (2006)
#5I agree with the sentiment, but who is actually claiming that TCL is a toy language? Random uninformed people on Reddit opine about all sorts of stuff.
It is an old language with lots of cruft, but it's been used in all sorts of places for something like 25 years. Perhaps people's experiences with the language are colored by using it as a means to customize behavior in some big hairy enterprise app.
Re: Tcl the misunderstood (2006)
#6An interesting corollary to concept 5 (the fact that everything in Tcl is a string) is that this means that Tcl is actually homoiconic. It does it completely differently from Lisp, but still ends up in the same place: code and data have the same representation.
Re: Tcl the misunderstood (2006)
#7TCL is great at being an embedded language, especially when you want something that looks like a DSL using safe-interpreters. (Basically, these are sandboxed interpreters with access to limited built-ins, plus any methods you might inject into the global namespace)
TCL lends easily shell-like syntax so it is great for adapting your DSL to a REPL and even maps fairly cleanly to REST.
Years ago, I built a REST-like API that had one URI to which one could POST a TCL script. That script in its most basic form would be a series of pipelined API calls. There was even limited transactional support. I saw this important for mobile applications as it would reduce latency.
While the scripts were technically TCL, it was easier for developers than Javascript or Ruby (which we also beta'ed). It didn't look as much like a programming language as it did a series of shell commands.
The biggest problem with the above is that TCL safe interpreter still allow loops and other blocking operations. It means that you need to write a reaper to kill long-running threads / processes.
Combining such techniques with ZeroVM (or even Docker, or both) would be interesting.
Re: Tcl the misunderstood (2006)
#8An interesting corollary to concept 5 (the fact that everything in Tcl is a string) is that this means that Tcl is actually homoiconic. It does it completely differently from Lisp, but still ends up in the same place: code and data have the same representation.
This is one the reasons I like parsing HTTP requests through TCL. Everything in HTTP is a string, there are no numerals. Typecasting arguments from query strings is the source of many ills. It isn't much of a problem with TCL since like HTTP, everything is a string.
Everything else about web service backends in TCL is pretty sad and frustrating, though. Unless it's embedded, anyway.
Re: Tcl the misunderstood (2006)
#9Back at the beginning of time I worked with Vignette StoryServer, which spun out of aolserver, one of the first "database-backed dynamic website" servers. The scripting language was TCL 7.something. I never encountered it again, but its elegance always stayed with me. Except for uplevel. Fucking evil.
uplevel allows you to write control structures like if, while, etc... in Tcl itself. Yes, that's something you need to be careful with because it's extremely powerful.
Re: Tcl the misunderstood (2006)
#10Although antirez made the sane choice of embedding Lua in Redis.