Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Tcl 9.0

tcl-lang.org

Post reply on HN
Print view View original

101–110 of 247 posts

Re: Tcl 9.0

#101

Post by progmetaldev »

em-bee wrote: post #65
throw0101b wrote: post #54

Earlier quoted context omitted.

One example from the document: > Consider the naive attempt to clean out the /tmp directory. > cd /tmp > foreach f [glob *] {file delete -force $f} > A file ~ or ~user maliciously placed in /tmp will have rather unfortunate consequences.

i once managed to create a directory named ~ using the mirror tool written in perl. then i naively tried to remove it using "rm -r ~" and started wondering why removing an empty directory would take so long, until it dawned on me... i learned a few new habits since then. i almost never use rm -r and i avoid "*" as a glob by itself. instead i always try to qualify "*" with a path, remove files first: "rm dir/*"; and t…

Very cool of you to post this. Too many people won't post stories like this, but I've done very similar multiple times. I think it definitely helps reinforce proper habits, and is the best way to cut your teeth on technology. It's also great for anyone new to read something like this, and be able to avoid something so devastating, and maybe make lesser mistakes, but still learn from both!

Re: Tcl 9.0

#102

Post by natrys »

Klonoar wrote: post #8

The only time I’ve dealt with Tcl in recent memory was for some MacPorts portfile stuff. Anybody using it for something else and can speak to why you’d use it today? Genuinely curious; I don’t hate the language but can never bring myself to enjoy it either.

I use it to write long running little scripts. It's better than shell, and imo more useful out of the box than Lua. They are basically for I/O (often using sqlite which it has great integration with, or using expect which is also great) so I don't care about performance, but I like that it requires much less memory compared to say Python for that kind of little things (there is also jimtcl which is also neat in this regard).

Re: Tcl 9.0

#103

Post by sshine »

mattw2121 wrote: post #75
sedatk wrote: post #53

I can't overstate my love for Tcl, yet I had only a little chance to use it when writing XiRCON IRC scripts back in the late 90's. Such an elegant language: simple, easy to learn, flexible. I call it Lisp for humans. I wish it were more popular. So glad to see that it's still alive and kicking.

Agreed, my only exposure to Tcl was writing IRC scripts for bots and I have nothing but fond memories of the experience.

Same. Such a simple life writing text-only event handlers.

Re: Tcl 9.0

#105

Post by progmetaldev »

kristopolous wrote: post #68
em-bee wrote: post #65

Earlier quoted context omitted.

i once managed to create a directory named ~ using the mirror tool written in perl. then i naively tried to remove it using "rm -r ~" and started wondering why removing an empty directory would take so long, until it dawned on me... i learned a few new habits since then. i almost never use rm -r and i avoid "*" as a glob by itself. instead i always try to qualify "*" with a path, remove files first: "rm dir/*"; and t…

I've long fantasized about a tool I call "expect" that safeguards against crazy stuff like that. It has a syntax of your expectations, functionally existing as a set of boundaries, and you can hook it to always run as a wrapper for some set of commands. It essentially stages the wrapped command and if none of the boundaries are violated it goes through. Otherwise it yells at you and you need to manually override it.…

When it comes to SQL, I will often write a SELECT with very explicit search (WHERE) criteria for this very reason. Then copying that statement, commenting the original, and pasting to change into an UPDATE or DELETE statement seems to be a technique that works well for me. The SELECT tells me exactly what I'm going to UPDATE or DELETE, and once I have that, changing the syntax is very minimal. In the case of an ORM, you might have to write a tool that only listens on LOCALHOST to run these statements first.

Re: Tcl 9.0

#106

Post by x-shadowban »

kristopolous wrote: post #68
em-bee wrote: post #65

Earlier quoted context omitted.

i once managed to create a directory named ~ using the mirror tool written in perl. then i naively tried to remove it using "rm -r ~" and started wondering why removing an empty directory would take so long, until it dawned on me... i learned a few new habits since then. i almost never use rm -r and i avoid "*" as a glob by itself. instead i always try to qualify "*" with a path, remove files first: "rm dir/*"; and t…

I've long fantasized about a tool I call "expect" that safeguards against crazy stuff like that. It has a syntax of your expectations, functionally existing as a set of boundaries, and you can hook it to always run as a wrapper for some set of commands. It essentially stages the wrapped command and if none of the boundaries are violated it goes through. Otherwise it yells at you and you need to manually override it.…

Oh yeah, re: SQL expect - I always wish joins had a "cardinality assertion", like a regex *?+ (or ! for exactly one)

Re: Tcl 9.0

#107

Post by bmacho »

oldlaptop wrote: post #93
bachmeier wrote: post #81

Really enjoy the language, even if I don't use it much these days. Does it still produce GUIs from 1995 on Linux? I'd still be using it today if it had halfway reasonable support for building GUIs on Linux, like they've had for ages on other platforms.

A theming engine went in something like 15 years ago now; the default theme looks rather dated, but there are plenty of others. See https://wiki.tcl-lang.org/page/List+of+ttk+Themes (though the screenshots of core themes are from 8.5/8.6 - default in particular has changed a bit in Tk 9). The "catch" is that the theming engine has its own new widgets, and so to be themed an application has to use the new API. Code fr…

Those are TK? They look good!

Re: Tcl 9.0

#108

Post by barosl »

em-bee wrote: post #65
throw0101b wrote: post #54

Earlier quoted context omitted.

One example from the document: > Consider the naive attempt to clean out the /tmp directory. > cd /tmp > foreach f [glob *] {file delete -force $f} > A file ~ or ~user maliciously placed in /tmp will have rather unfortunate consequences.

i once managed to create a directory named ~ using the mirror tool written in perl. then i naively tried to remove it using "rm -r ~" and started wondering why removing an empty directory would take so long, until it dawned on me... i learned a few new habits since then. i almost never use rm -r and i avoid "*" as a glob by itself. instead i always try to qualify "*" with a path, remove files first: "rm dir/*"; and t…

> if "rm -i" is the default the "rm" level gets disabled, because "rm -i -f" is the same as "rm -f"

You can use "\rm" to invoke the non-aliased version of the command. I made "rm -i" the default using an alias and occasionally use "\rm" to get the decreased safety level you described. I think it is more convenient that way.

Re: Tcl 9.0

#109

Post by sfink »

mzs wrote: post #100
sfink wrote: post #95

Earlier quoted context omitted.

My main safety habit is to avoid slashless paths. Bad: rm * Okay: rm ./* rm /tmp/d/* rm */deadmeat rm d/* Then again, I commonly use dangerous things like `mv somefile{,.away}` that are easy to get wrong, so maybe don't trust my advice too much.

rm -rf "$TSTDIR"/etc is pretty dangerous when you forget to set the env var

Fair! Upvoted.

I guess I'm not likely to type that into the shell, or if I do, I then tab-complete to expand it.

I could definitely see myself using that in a shell script, though. I tend to do validity checks there:

    if ! [ -d "$TSTDIR" ]; echo "$TSTDIR not found, stupid" >&2; exit 1; fi
but that's kind of irrelevant, since if I need it to exist then I won't be removing it. Plus, I could totally see myself doing

    if [ -d "$TESTDIR" ]; then
      rm -rf "$TSTDIR"/etc
    fi

Re: Tcl 9.0

#110

Post by rixed »

em-bee wrote: post #65
throw0101b wrote: post #54

Earlier quoted context omitted.

One example from the document: > Consider the naive attempt to clean out the /tmp directory. > cd /tmp > foreach f [glob *] {file delete -force $f} > A file ~ or ~user maliciously placed in /tmp will have rather unfortunate consequences.

i once managed to create a directory named ~ using the mirror tool written in perl. then i naively tried to remove it using "rm -r ~" and started wondering why removing an empty directory would take so long, until it dawned on me... i learned a few new habits since then. i almost never use rm -r and i avoid "*" as a glob by itself. instead i always try to qualify "*" with a path, remove files first: "rm dir/*"; and t…

You could also create a file named "-i" in your home dir.
Post reply on HN