dict makes named parameters easy.
proc example {a b args} {
if {[llength $args] == 1} {
set args [lindex $args 0] ;# work with unexpanded args
}
# establish defaults
set args [dict merge {default value} $args]
# use elements from dict
fn [dict get $args parameter]
# (dangerously) use args dict as variables
dict with args {
lappend parameter "END"
}
}Alternatively, one can use an array to the same effect:
proc example {a b args} {
if {[llength $args] == 1} {
set args [lindex $args 0] ;# work with unexpanded args
}
# establish defaults
array set A {default value}
# pour in supplied args
array set A $args
# use elements from A
fn $A(parameter)
# array elements are variables, so there is no need to unpack them explicitly.
lappend A(parameter) "END"
}slebetman: Also see optproc for another take on named parameters.
SL 9/9/08: This needs some more explanation.