Questions tagged [upvar]
23 questions
13
votes
4 answers
how the upvar command works in TCL?
I have a question about upvar command in TCL. Using upvar command, we have have a reference to a global variable or a local variable in other procedure. I saw the following code:
proc tamp {name1 name2} {
upvar $name1 Ronalod
upvar $name2…
user707549
5
votes
3 answers
Difference between upvar 0 and upvar 1 in TCL
Can anyone let me know the difference between upvar 0 and upvar 1 in TCL, how we can use in real time. Kindly, if someone explain with example, it makes me more clear.
velpandian
- 431
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3
votes
3 answers
TCL - return variable vs upvar and modify
Would like to take an advice from TCL professionals for best practice.
Say you want to construct a list with a specific data by using a proc. Now which is the best way?
proc processList { myList } {
upvar $myList list_
#append necessary data…
Narek
- 38,779
- 79
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3
votes
3 answers
What purpose does upvar serve?
In the TCL code that I currently work on, the arguments in each procedure is upvar'ed to a local variable so to speak and then used. Something like this:
proc configure_XXXX { params_name_abc params_name_xyz} {
upvar $params_name_abc abc
…
user2311285
- 437
- 6
- 14
3
votes
2 answers
error : Can't read "n" : no such variable in tcl
proc rep {name} {
upvar $name n
puts "nm is $n"
}
In the above procedure, 'name' is a parameter which is passed to a procedure named 'rep'. When I run this program I got "error : Can't read "n" : no such variable". Could any one tell me…
Praveen kumar
- 597
- 2
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- 26
2
votes
1 answer
What is the difference between a TCL namespace and a stack frame?
Upvar creates a link to a variable in a different stack frame, sometimes called a call stack, or a different scope.
Upvar is also used to create an alias for a global (or namespace) variable 2. But a namespace is created only by the namespace eval…
Otto Hunt
- 107
- 1
- 7
2
votes
1 answer
Tcl upvar to a variable in another proc
I have two procs: From MAIN I call another proc Glob.
$Allforces is a list of lists.
proc ::MAIN {} {
# something
::Glob $AllForces
}
proc ::Glob {Input} {
upvar $Input AllForces
# do something
}
I get "No such variable" as an…
Lumpi
- 2,697
- 5
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- 47
1
vote
3 answers
Unable to pass a variable to a procedure using upvar in Tcl
I need a procedure that will be able to access, read and change a variable from the namespace of the caller. The variable is called _current_selection. I have tried to do it using upvar in several different ways, but nothing worked. (I've written…
SIMEL
- 8,745
- 28
- 84
- 130
1
vote
1 answer
Why does this code with TCL Upvar command generate an error?
So I thought I understood how the TCL upvar command worked, but for some reason I cannot seem to trace why this code generates an error -
#!/usr/bin/env tclsh
proc run_check {} {
set src dut.acore.B2.Vin
set conlist1 [list dut.acore.B2.Vin…
Rajat Mitra
- 167
- 1
- 11
1
vote
2 answers
How to access a variable defined in proc 'a' from a different proc 'b' which does not call proc 'a'?
I am trying to execute a tcl script which makes exclusive calls to procs a and b. The two procs are not related to each other.
proc a {} {
set var1 "a"
}
proc b {} {
# Do something here with: $var1
}
# script.tcl
a
b
I do not have access…
vandan
- 13
- 2
1
vote
1 answer
Expected TCL: upvar vs namespace variable performance
Is there an expected, by spec/implementation, difference between accessing namespace variables vs. upvar.
I have to use a call-back function. I cannot just pass an argument.Empirically, upvar wins. But is that expected, in all reasonable…
user1134991
- 3,003
- 2
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- 35
1
vote
2 answers
Tcl upvar performance improvement vs. direct pass
This pertains to Tcl 8.5
Say I have a very large dictionary.
From performance points of view (memory footprint, etc), assuming that I do not modify the dictionary, should upvar provide a massive performance improvement in terms of memory? I am using…
user1134991
- 3,003
- 2
- 25
- 35
1
vote
1 answer
Elevating a variable scope without knowing its name
I need to 'upvar' variables from a source'd file (and I don't know their names)
Let's say I have a TCL file containing:
set v 7
Now this:
proc p {} {
source t.tcl
}
p
puts $v
# => can't read "v": no such variable
The file t.tcl must not be…
Gert Gottschalk
- 1,658
- 3
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1
vote
1 answer
Usage of namespace/uplevel/global in TCL
I have a script like this :
proc subProc1 { } {
puts $var1
}
proc subProc2 { } {
puts $var2
}
proc mainProc { args } {
# Define many variables
subProc1
subProc2
#etc.
}
I would like subProc1 and subProc2 to have variables…
little-dude
- 1,544
- 2
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- 33
1
vote
1 answer
tcl proc using upvar resulting in history(nextid)
I'm getting this weird issue.
i'm using tcl 8.3
after i define this proc in a tcl shell
% proc incr { varName {amount 1}} {
puts $varName
upvar #0 $varName var
puts $varName
if {[info exists var]} {
set var [expr $var +…
nikhiljakks
- 13
- 3