TCL Variable substitution problem...

[globemast]

Hello,

I have the following problem regarding TCL variable substitution

I have the following code in ns2:

set Appl_udp_0_1 [new Agent/UDP]
$ns attach-agent $n(0) $Appl_udp_0_1
$Appl_udp_0_1 set class_ 1

where the first number in $Appl_udp_0_1 (i.e 0) characterizes the node the UDP agent is running and the second number (ie. 1) the flow id.

In a procedure i have the following parameters

proc test { src flowid} {

global Appl_udp_$src_$flowid

}

My problem is that TCL takes as variable the $src_ (including the "_" character) and as a result shows that a variable $src_ does not exist.

Is there a way i can make the variable expression to stop before the "_" character ??

Thank you.

 

[cptk]

Try encapsulating the variable name only with {}'s .

e.g. -

set VAR1 "abc"
puts ${VAR1}_123
--> abc_123

... Hope that helps!

 

[globemast]

Ok if i substitute include the variable in curly brackets it recognises the correct variable, but now it gives me another problem.


If i have the following:

$ns detach-agent $n(4) $Appl_udp_${dest}_${flowid}

it tells me that variable Appl_udp_ doesn't exist...

It seems it reads the variable up to the second "_" character.

Any suggestions?


Thank you in advance.

 

[cptk]

Yeah, I think I understand your situation ...

You need to use name spaces "::"

e.g. -

> set VAR1 "dog"
> set X "1"

puts ${VAR}${X}
--> can't read "VAR": no such variable

but, if you do this:

> puts [set ::VAR${X}]
--> dog