The simplest way to call a procedure, namespaced or not, is (1) to give its full name, with arguments. For a proc exported in a namespace, you might also (2) import it so you call it by 'basename', omitting the namespace path. Also, you can (3) instruct any interpreter that a proc name like foo is an alias for another like bar, which may also have constant arguments (minor commands) appended:
interp alias {} foo {} bar grillFinally, you can (4) indirectly wrap a proc invocation in another proc: proc foo {x y} {bar $x $y}Miguel Sofer has timed these four alternatives, and to our surprise found out that aliassing (3) takes double the time of (1) or (2), so even (4) is clearly better: ...on 8.4a2, at least! On my notebook I getdirect : 299050 microseconds per iteration import : 288499 microseconds per iteration interp alias : 638389 microseconds per iteration indirect : 365086 microseconds per iterationwhen I run "t 10000" (a few times, until timings stabilize ...) after defining the script below.
Michael Schlenker has run the test with 8.4.1 (w2k, PII 350) and got:
direct : 361965 microseconds per iteration import : 399422 microseconds per iteration interp alias : 497514 microseconds per iteration indirect : 482034 microseconds per iterationSeems like the penalty is getting smaller.NEM 2008-11-13: Updated for Tcl 8.6a4 (MacOS X, dual-core 2GHz):
direct : 17720 microseconds per iteration import : 15187 microseconds per iteration interp alias : 19742 microseconds per iteration indirect : 21327 microseconds per iterationSeems like the overhead has vanished.
namespace eval mig {
proc test {} {set ::a 5}
namespace export *
}
namespace import mig::*
interp alias {} test2 {} ::mig::test
proc test3 {} {::mig::test}
proc t {n} {
set t1 [time {
for {set nn $n} {[incr nn -1]} {} {
::mig::test
}
}]
set t2 [time {
for {set nn $n} {[incr nn -1]} {} {
test
}
}]
set t3 [time {
for {set nn $n} {[incr nn -1]} {} {
test2
}
}]
set t4 [time {
for {set nn $n} {[incr nn -1]} {} {
test3
}
}]
puts "\n"
puts "direct : $t1"
puts "import : $t2"
puts "interp alias : $t3"
puts "indirect : $t4"
}RS - I would not have expected such a penalty for an interp alias. What do you others think?DKF: The "surprising" thing is how different aliases are from namespace imports.JBR: Or even why an import is faster than directly naming the proc??
