Execute Tcl Online

puts "Truth Table based Gate Level Simulator"
# boolean equation provided as input and displays it
puts -nonewline "Enter a boolean expression: "
flush stdout
set exp [gets stdin]
puts $exp
set variables [lsort -unique [regexp -inline -all {\$\w+} $exp]]
set length [llength $variables]
# differentiating among the variables as hey can be present number of times
set command [list format [string repeat "%s\t" $length]%s]
append command " {*}\[[list subst $variables]\] \[[list expr $exp]\]" 
set command "puts \[$command\]"
#calculates the value for each input combinations 
foreach v [lreverse $variables] {
set command [list foreach [string range $v 1 end] {0 1} $command]
}
#displays the output
puts " "
puts [join $variables \t]\tResult
apply [list {} $command]