passing a list into a procedure in tcl

Question

I want to pass a list into a procedure but not sure how to. I've looked at some examples of how to do this but the examples are too complicated and I don't understand them. The list and procedure are shown below.

set RS_CheckBoxes [list kl15_cb din1_cb din2_cb din3_cb din4_cb \
                dinnc_cb ain1_cb ain2_cb ain3_cb ain4_cb a_cb \
                b_cb u_cb v_cb w_cb sin_cb cos_cb th1_cb th2_cb hvil_cb]

tk::button .rs.enter -height 2 -text "Enter" -width 10 -command {x $RS_CheckBoxes}

proc x {$RS_CheckBoxes} {

if {$RS_CheckBoxes} {
puts "ON"
} else {
puts "OFF"
}
}

At present I'm using the below code but want to reduce the amount of lines.

tk::button .relSel.b -height 2 -text "Enter" -width 10 -command {if {$kl15_cb} {
 puts "$kl15_cb"
 } else {
 puts "$kl15_cb"
 }

 if {$dinnc_cb} {
 puts "$dinnc_cb"
 } else {
 puts "$dinnc_cb"
 }

 if {$din1_cb} {
 puts "$din1_cb"
 } else {
 puts "$din1_cb"
 }

 if {......... etc}
 ............. etc

Answer 1

Your description is not entirely clear. Do you want to pass a list of global variable names into a proc and then print ON or OFF based on their boolean value?

Currently you just seem to be printing the value of the variables in a very complicated way.

if {$dinnc_cb} {
    puts "$dinnc_cb"
} else {
    puts "$dinnc_cb"
}

is equal to puts $dinnc_cb unless you want the code to throw an error when the value cannot be interpreted as a boolean.

If my understanding is correct, try this:

proc x {varlist} {
    foreach varname $varlist {
        upvar #0 $varname var
        puts "$varname: [lindex {ON OFF} [expr {!$var}]]"
    }
}

The upvar creates a link from the global variable in $varname to the local variable var. You can then use that to check the global variable.

To include a check that the variable is actually set:

proc x {varlist} {
    foreach varname $varlist {
        upvar #0 $varname var
        if {[info exists var]} {
            puts "$varname: [lindex {OFF ON} [string is true -strict $var]]"
        } else {
            puts "$varname: INDETERMINATE"
        }
    }
}