lassign {a b c} x y z ;# Empty return
puts $x ;# Prints "a"
puts $y ;# Prints "b"
puts $z ;# Prints "c"
lassign {d e} x y z ;# Empty return
puts $x ;# Prints "d"
puts $y ;# Prints "e"
puts $z ;# Prints ""
lassign {f g h i} x y ;# Returns "h i"
puts $x ;# Prints "f"
puts $y ;# Prints "g"
The lassign command has other uses. It can be used to create the analogue of the “shift” command in many shell languages like this:
set ::argv [lassign $::argv argumentToReadOff]