Tcl/Tk 8.5 Programming Cookbook

Variables

As with all the programming languages, it is the variable that allows for true flexibility and usability. Tcl differs from some scripted languages, as, there is no need to implicitly declare the variable type. For example a variable of "3" will be stored within Tcl with the same internal representation, as if it have been defined as the integer 3. If the variable is then used in a calculation, Tcl will then convert it to an integer for computation. This is referred to as shimmering in Tcl.

Basic variable commands

Variable command	Explanation
global var	This command is used to declare a global variable. It is only required within the body of a procedure.
incr var value	This command will increment the value stored in var by the ...