Mathematical set based functions
Of obvious enough kind, but important, and underused, I guess. Page started by Theo Verelst
These are the first definitions:
proc set:empty {} {return {}}
proc set:add {a b} {return [set:union $a $b]}
proc set:isempty {s} {expr {[llength $s] == 0}}
proc set:size {s} {return [llength $s]}
proc set:union {a b} {
set o {}
foreach i $a {
if {[lsearch $b $i] < 0} {lappend o $i}
}
set o [concat $o $b]
return $o
}
proc set:intersection {a b} {
set o {}
foreach i $a {
if {[lsearch $b $i] >= 0} {lappend o $i}
}
return $o
}
proc set:difference {a b} {
foreach i $b {
if {[set idx [lsearch $a $i]] >= 0} {
set a [lreplace $a $idx $idx]
}
}
return $a
}