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Top Forums Shell Programming and Scripting Replacement for eval in Perl?????? Post 302211238 by cbkihong on Thursday 3rd of July 2008 02:00:58 AM
Old 07-03-2008
Quote:
Originally Posted by Annihilannic
There is an eval statement in perl as well.
Please, do not advocate the use of eval unnecessarily because it is a security risk. It should be reserved with tightly controlled commands and in this case this is certainly not tight controlled.

Perl does allow you reference a "variable variable" (a variable whose name is the value held by a variable). That works unless you are in strict mode, in which case an exception will be thrown.

Code:
$num = 60;
$varname = 'num';
print $$varname;    # 60

Even though that works, think about it carefully whether you really need that because not many use cases actually need this.
 

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global(n)						       Tcl Built-In Commands							 global(n)

__________________________________________________________________________________________________________________________________________________

NAME
global - Access global variables SYNOPSIS
global varname ?varname ...? _________________________________________________________________ DESCRIPTION
This command has no effect unless executed in the context of a proc body. If the global command is executed in the context of a proc body, it creates local variables linked to the corresponding global variables (though these linked variables, like those created by upvar, are not included in the list returned by info locals). If varname contains namespace qualifiers, the local variable's name is the unqualified name of the global variable, as determined by the namespace tail command. varname is always treated as the name of a variable, not an array element. An error is returned if the name looks like an array element, such as a(b). EXAMPLES
This procedure sets the namespace variable ::a::x proc reset {} { global a::x set x 0 } This procedure accumulates the strings passed to it in a global buffer, separated by newlines. It is useful for situations when you want to build a message piece-by-piece (as if with puts) but send that full message in a single piece (e.g. over a connection opened with socket or as part of a counted HTTP response). proc accum {string} { global accumulator append accumulator $string } SEE ALSO
namespace(n), upvar(n), variable(n) KEYWORDS
global, namespace, procedure, variable Tcl global(n)
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