Hm, what about this little baby:
proc ::xotcl::gc {name1 name2 op} {
::uplevel $name1 destroy}
Class instproc private {varname args} {
::upvar $varname v ::set v $varname ::uplevel trace variable $varname u ::xotcl::gc ::eval [self] create $varname $args
}
Hi Zoran, very nice!
...below is a still simpler version...
with the same idea, we we can make a bind command, where we can bind an object to a variable in the sense that
a) the object is deleted, when the variable is unset b) the object can provide a print-value, when someone read the value of the variable
this might be useful for e.g. associations as well, where you have an instance variable refering to an object, and once you delete the object (with its variables) you want to destroy the referred object (or decrement a reference counter)
-gustaf PS: i have a little bad feeling about filters/mixins and uplevel/upvar and friends.
#### private proc ::xotcl::gc {name1 name2 op} { puts "destroying $name1" $name1 destroy }
Class instproc private {varname args} { ::uplevel trace variable $varname u ::xotcl::gc ::uplevel set $varname [::eval [self] create $varname $args] }
##### bind proc ::xotcl::value {name1 name2 op} { uplevel set $name1 [list [$name1 value]] }
Object instproc bind {object varname} { ::uplevel trace variable $varname u ::xotcl::gc ::uplevel trace variable $varname r ::xotcl::value ::uplevel set $varname $object }
#### usage Class foo foo private bar
Class C -parameter i C instproc value {} { return "[self]'s value is [[self] incr i]" }
Object o o proc test1 {} { Object private o1 puts ... o1 set x 1 puts ... } o proc test2 {} { C o2 -i 11 puts ... [self] bind o2 o2 puts ...$o2... puts ...$o2... }
puts ===== o test1 puts ===== o test2 puts =====