Getting the value without direct usage of the variable

set a b
set b 7

Now I have to print the value of a as 7. But should not use b or any other new variable anywhere. How could this be achieved?

On 7/30/12 4:43 AM, Shimsha wrote:
> set a b
> set b 7
>
> Now I have to print the value of a as 7. But should not use b or any other new variable anywhere. How could this be achieved?

First off, the way you are approaching the problem is very likely wrong --
consider using arrays instead.

If you insist on going about your code this way, read and understand the
following man pages:
set
subst
upvar



--
+------------------------------------------------------------------------+
| Gerald W. Lester, President, KNG Consulting LLC |
| Email: Gerald.Lester@kng-consulting.net |
+------------------------------------------------------------------------+

On 7/30/12 4:43 AM, Shimsha wrote:
> set a b
> set b 7
>
> Now I have to print the value of a as 7. But should not use b or any other new variable anywhere. How could this be achieved?

First off, the way you are approaching the problem is very likely wrong --
consider using arrays instead.

If you insist on going about your code this way, read and understand the
following man pages:
set
subst
upvar



--
+------------------------------------------------------------------------+
| Gerald W. Lester, President, KNG Consulting LLC |
| Email: Gerald.Lester@kng-consulting.net |
+------------------------------------------------------------------------+

On Monday, July 30, 2012 4:43:48 AM UTC-5, Shimsha wrote:
> set a b
>
> set b 7
>
>
>
> Now I have to print the value of a as 7. But should not use b or any other new variable anywhere. How could this be achieved?

I don't consider it wrong. I use indirection such as this a lot. The simple answer is: puts [set $a]

Of course as mentioned there are other methods as well

Le 30/07/2012 11:43, Shimsha a écrit :
> set a b
> set b 7
>
> Now I have to print the value of a as 7. But should not use b or any other new variable anywhere. How could this be achieved?

If your goal is to define a as a reference or alias to b, upvar is what
you're looking for:

upvar #0 a b
set b 7
puts $a
=> 7

(the #0 means that a and b must be in the same context)

Else, you have to be a little more explicit about what you intent to
achieve.

* Frederic Bonnet <fredericbonnet@free.fr>
| upvar #0 a b
| set b 7
| puts $a
| => 7
>
| (the #0 means that a and b must be in the same context)

I *think* that should be plain 0 here, since #0 addresses the global
namespace. Makes a difference inside procs.

R'

Le 30/07/2012 17:43, Ralf Fassel a écrit :
> * Frederic Bonnet <fredericbonnet@free.fr>
> | upvar #0 a b
> | set b 7
> | puts $a
> | => 7
>>
> | (the #0 means that a and b must be in the same context)
>
> I *think* that should be plain 0 here, since #0 addresses the global
> namespace. Makes a difference inside procs.
>
> R'
>
Oops you're right, my bad. :blush: