tcl: how to execute tcl command with custom list argument - tcl

I have this example tcl code that works by itself:
layout peek -celltext "CellA" "CellB"
I would like to have the a list storing CellA and CellB such that I want to execute something like
set list [list "CellA" "CellB"]
set OUTPUT [layout peek -celltext [exec echo $list]]
Unfortuantely, spending 2 hours and various combination isn't getting me anywhere. Any ideas on what I need to do? Forgive me as i'm not strong in Tcl programming.

Related

invalid command name "2001:172:16:21::36"

I need to assign my final variable with the following string UDP6:[2001:172:16:21::36]
set ipAddr1 "UDP6,2001:172:16:21::36"
set ipAddrArr [split $ipAddr1 ","]
set ipAddrArr11 [lindex $ipAddrArr 0]
set ipAddrArr12 [lindex $ipAddrArr 1]
set tmp ":\["
set ipAddr1Part [join "$ipAddrArr11 $ipAddrArr12" $tmp]
set tmp1 "]"
set ipAddrFinal [join "$ipAddr1Part$tmp1"]
When I run the tcl script, it gives invalid command name as 2001:172:16:21::36.
I have printed ipAddrFinal value , it gives the expected one UDP6:[2001:172:16:21::36]
pls help me out? what am I missing
The script as you have written it works fine; it assigns the string UDP6:[2001:172:16:21::36] to the variable ipAddrFinal. However, since it contains characters that are Tcl metacharacters in some contexts, I suspect that you are then using the string in an unsafe way, most likely with eval or possibly with subst or uplevel. If you look at the stack trace of the error (in the errorInfo global variable by default) you should be told pretty exactly where the offending code is; it might give a few places you need to look, but it usually isn't too hard to hunt down where the problem originates from.
If your problem comes from uplevel, you are probably going to need to use list to construct a command; 99.99% of all problems with uplevel are handled that way. If your problems come from eval, the chance's good that you need to switch to using expansion syntax. If your problems come from subst or are otherwise still deeply confusing, check back with us (with your stack trace if you are not sure where the problem is coming from).
Example of a fix for eval:
Change:
set action "puts \"IP\\ address\\ is\\ $ipAddrFinal\""
eval $action
to:
set action [list puts "IP address is $ipAddrFinal"]
{*}$action
NB: The error from doing the eval is a reasonable example too:
invalid command name "2001:172:16:21::36"
while executing
"2001:172:16:21::36"
("eval" body line 1)
invoked from within
"eval $action"
Note that it says that it's in an eval, and that points squarely to unsafe script construction. The list command does safe script construction as one of its bonus superpowers.

Difference tcl script tkconsole to load gro file in VMD

My problem is simple: I'm trying to write a tcl script to use $grofile instead writing every time I need this file name.
So, what I did in TkConsole was:
% set grofile "file.gro"
% mol load gro ${grofile}
and, indeed, I succeeded uploading the file.
In the script I have the same lines, but still have this error:
wrong # args: should be "set varName ?newValue?"
can't read "grofile": no such variable
I tried to solve my problem with
% set grofile [./file.gro]
and I have this error,
invalid command name "./file.gro"
can't read "grofile": no such variable
I tried also with
% set grofile [file ./file.gro r]
and I got the first error, again.
I haven't found any simple way to avoid using the explicit name of the file I want to upload. It seems like you only can use the most trivial, but tedious way:
mol load file.gro
mol addfile file.xtc
and so on and so on...
Can you help me with a brief explanation about why in the TkConsole I can upload the file and use it as a variable while I can not in the tcl script?
Also, if you have where is my mistake, I will appreciate it.
I apologize if it is basic, but I could not find any answer. Thanks.
I add the head of my script:
set grofile "sim.part0001_protein_lipid.gro"
set xtcfile "protein_lipid.xtc"
set intime "0-5ms"
set system "lower"
source view_change_render.tcl
source cg_bonds.tcl
mol load gro $grofile xtc ${system}_${intime}_${xtcfile}
It was solved, thanks for your help.
You may think you've typed the same thing, but you haven't. I'm guessing that your real filename has spaces in it, and that you've not put double-quotes around it. That will confuse set as Tcl's general parser will end up giving set more arguments than it expects. (Tcl's general parser does not know that set only takes one or two arguments, by very long standing policy of the language.)
So you should really do:
set grofile "file.gro"
Don't leave the double quotes out if you have a complicated name.
Also, this won't work:
set grofile [./file.gro]
because […] is used to indicate running something as a command and using the result of that. While ./file.gro is actually a legal command name in Tcl, it's… highly unlikely.
And this won't work:
set grofile [file ./file.gro r]
Because the file command requires a subcommand as a first argument. The word you give is not one of the standard file subcommands, and none of them accept those arguments anyway, which look suitable for open (though that returns a channel handle suitable for use with commands like gets and read).
The TkConsole is actually pretty reasonable as quick-and-dirty terminal emulations go (given that it omits a lot of the complicated cases). The real problem is that you're not being consistently accurate about what you're really typing; that matters hugely in most programming languages, not just Tcl. You need to learn to be really exacting; cut-n-paste when creating a question helps a lot.

Reordering the contents of a file using tcl

I’m a newbie to Tcl and code writing in general. I have what seems like a simple coding issue that I have about 10 hrs into that I can’t seem to resolve.
I have a file that contains a list of nets clk123, n789, clk456, n246…. I need to reorder the list so that the clk* nets appear first when outputted. I can read the files in question and output the contents to the monitor or a file. But, I’m not able to find a way to reorder the list. I’ve spent so much time researching this that I’m now completely confused. Can someone offer a suggestion?
If there's just clk* and n* nets, a simple sort should be sufficient:
package require fileutil
proc sort data {
set lines [split $data \n]
set lines [lsort $lines]
join $lines \n
}
::fileutil::updateInPlace thefile.txt sort
Documentation: fileutil package, join, lsort, package, proc, set, split

How to keep commands quiet in TCL?

How to execute set command without printing output on the screen? I want to read a file without displaying the contents on the screen.
set a [open "giri.txt" r]
set b [read $ifile]
What you're observing is just the standard behaviour of an interactive Tcl shell: each Tcl command returns a result value, and a return code. If the Tcl shell is interactive (that is, its input and output streams are connected to a terminal), after executing each command, the string representation of the result value the command returned is printed, and then the prompt is shown again. If the shell is not interactive, no results are printed and no prompt is shown.
(On a side note, such behaviour is ubiquitous with interpreters — various Unix shells, Python and Ruby interpreters do the same thing.)
If you want to inhibit such printouts in an interactive session (comes in handy from time to time), a simple hack to achieve that is to chain the command you want to "silence" with a "silent" command (producing a value whose string representation is an empty string), for instance:
set a [open "giri.txt" r]; list
Here, the list returned by the list command having no arguments is an empty list whose string representation is an empty string. In an interactive shell, this chain of commands will output literally nothing.
It bears repeating that such a hack might only ever be needed in an interactive session — do not use it in scripts.
In Mentor ModelSim Tcl it is possible to do:
quietly set answer 42
Also in Mentor Questa:
help quietly
The quietly command turns off transcript echoing for the specified command.
You can turn this off in an interactive tclsh
set tcl_interactive false
but that will also turn off the prompt.

Finding which interp one is in

I'm debugging some Tcl code which is using child interpreters, and not being familiar with the code, it would be handy to sprinkle some "puts" showing the path to the current interpreter to get a handle on what the code is doing. Is there a way in Tcl 8.4 to determine which interpreter one is running in?
No, there is no way to just pick the information up (it would violate the isolation principle). But you can pass that information into the sub-interpreters after you create them easily enough:
set i [interp create]
$i eval [list set ::myInterpName $i]