KPV After having read a criticism of tcl that it doesn't have true pass by reference--you have to fake it with using upvar--I thought I'd write a tcl-only clone of proc called xproc that will automatically give you pass by reference ala C++ syntax. Specifically, you say proc myproc {arg1 &arg2 arg3 &arg4} {body} and arg2 and arg4 will automatically be pass by reference.
proc xproc {pname arglist body} {
set newarglist {}
set ups ""
foreach arg $arglist {
if {[string match "&*" $arg]} {
set arg [string range $arg 1 end]
append ups "upvar 1 \$_$arg $arg;"
lappend newarglist _$arg
} else {
lappend newarglist $arg
}
}
set newbody [concat $ups $body]
set newproc [list proc $pname $newarglist $newbody]
eval $newproc
}Here's a sample usage:
xproc myproc {&arr} {
foreach n [array names arr] {
puts "arr($n) => $arr($n)"
}
}
array set myarray {1 one 2 two 3 three}
myproc myarray