I want to eat my list cake and have its elements

#!/usr/bin/tclsh

proc libfunc_args { filename } {
        set r { }
        foreach i [split $filename "/"] {
                lappend r $i
        }
        return $r
}

proc vectors { dummy tool_options } {
        set input_file "/etc/hosts"
        set command { }
        foreach opt $tool_options {
                set x [expr "\"$opt\""]
                lappend command $x
                puts "opt: $opt -> $x"
        }

        return $command
}

set cmd [vectors "dummy" { "hello" "world" "a sentence" "[libfunc_args \$input_file]" }]
foreach c $cmd {
        puts "command item: $c"
}


Actual output:

opt: hello -> hello
opt: world -> world
opt: a sentence -> a sentence
opt: [libfunc_args $input_file] -> {} etc hosts
command item: hello
command item: world
command item: a sentence
command item: {} etc hosts

Desired output:

opt: hello -> hello
opt: world -> world
opt: a sentence -> a sentence
opt: [libfunc_args $input_file] -> {} etc hosts
command item: hello
command item: world
command item: a sentence
command item: {}
command item: etc
command item: hosts