Question

I have the following basic code:

proc test {} { 
    set my_var2 3
    foreach iter {1 2 3} {
        set my_var1 4
        set my_var2 5
        puts "Inside: $my_var1 $my_var2
"  
    }
    puts "outside $my_var1, $my_var2
"    ;#WHY IT DOES NOT GIVE ERROR HERE!
}
test  ;#calling the function

该方案的产出是:

Inside: 4 5

Inside: 4 5

Inside: 4 5

outside 4, 5

Now my confusion is since my_var1 is define only in the local scope of foreach loop why its value is available even outside the loop? In other words what determines the scope of a variable in Tcl? Thanks a lot for the help!

Answer 1

http://www.tcl.tk/man/tcl/tutorial/Tcl13.html。《技术手册》:

Tcl evaluates variables within a scope delineated by procs, namespaces [...], and at the topmost level, the global scope.

因此, for虫不会产生新的范围,其所有变数都由原体来限定。

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