proc SET         {l1 l2} { set l1 "$l1 $l2" }
proc APPEND      {l1 l2} { append l1 " $l2" }
proc APPEND2     {l1 l2} { append l1 " " $l2 } ; # LH, 2008-06-12: Should be better than APPEND, since it avoids copying the $l2 data twice!
proc CONCAT      {l1 l2} { set l1 [concat $l1 $l2] }
proc EVAL/LAPPEND {l1 l2} { eval [list lappend l1] $l2 }
proc FOREACH/LAPPEND {l1 l2} {foreach i $l2 {lappend l1 $i} ; set l1}
proc EXPAND      {l1 l2} { lappend l1 {*}$l2 } ; # requires Tcl 8.5
set cases "SET APPEND APPEND2 CONCAT EVAL/LAPPEND FOREACH/LAPPEND"
if {![catch {package require Tcl 8.5}]} then {lappend cases EXPAND}

proc makeList {len item} {
    for {set i 0} {$i< $len} {incr i} {
        lappend res $item
    }
    return $res
}

proc testem {len} {
    global cases
    set res {}
    foreach p $cases {
        catch {unset l1}
        catch {unset l2}
        set l1 [makeList $len a]
        set l2 [makeList $len b]
        puts -nonewline stderr "$p..." ; flush stderr
        lappend res $p,$len [lindex [time {llength [$p $l1 $l2]} 1000] 0]
    }
    return $res
}


foreach l {10 100 1000 10000} {
    puts -nonewline stderr "testing size $l..." ; flush stderr
    array set data [testem $l]
    puts stderr done ; flush stderr
}

puts "Tcl Version - [info patchlevel]\n"

set fmtstr "| %15s | %7.1f | %7.1f | %7.1f | %7.1f |"
set divid  "|-----------------|---------|---------|---------|---------|"
set ends   "|---------------------------------------------------------|"

puts $ends
puts [format $fmtstr Method 10 100 1000 10000]
puts $divid

foreach p $cases {
    puts [format $fmtstr $p \
                $data($p,10) $data($p,100) \
                $data($p,1000) $data($p,10000)]
}

puts $ends

set list [lrepeat 100 asdf]; list
proc a {} {list {*}$::list {*}$::list}
proc b {} {concat $::list $::list}
a; list
b; list
time a 1000000; # 2.332994 microseconds per iteration
time b 1000000; # 1.583927 microseconds per iteration