As the itcl::class is a
tcl command, you can insert code into the
class declaration.
It is common C++ practice to have set/get methods to protect the variables in an object from manipulation outside the class.
This sample class creates a set of methods to set and enquire a list of protected variables.
console show
package require Itcl
itcl::class tclass {
foreach v {time distance} {
method get$v {} [subst -nocommands { return [subst $$v] }]
method set$v nuval [subst -nocommands { set $v \$nuval } ]
protected variable $v "Var $v"
}
constructor {} { puts "Constructs $this" }
method speed {} { return [expr {[getdistance]/[gettime]}]}
}
tclass a
a setdistance 2
a settime 3.0
puts "Travelled [a getdistance] taking Time [a gettime] so speed is [a speed]"The variable list can be arbitrarily long of course when this would save considerable typing and validation effort. The code can include any of the
itcl::class constructs. If you wish the variable list to be a variable in the class then it must be a
common variable so that it is available at class creation time:
itcl::class tclas2 {
common vars {time distance power}
foreach v $vars {
method get$v {} [subst -nocommands { return [subst $$v] }]
method set$v nuval [subst -nocommands { set $v \$nuval } ]
protected variable $v "Var $v"
}
constructor {} { puts "Constructs tclas2 $this" }
method showVarsandMethods {} { puts "Variables with get/set methods exist for: $vars.\nMethods are: [info function]" }
}
tclas2 b
b showVarsandMethods This example shows that setpower, getpower, set/getdistance and set/gettime are all methods of the class tclas2 even though the functions are not explicitly declared.
Entered by
GWM.
GWM an improvement places the make get and set methods in a proc 'makegetset' which can be referred to by all classes in a program.
proc makegetset {args} {
foreach {vn val} $args {
uplevel 1 public variable $vn $val
uplevel 1 public method set$vn \{v\} \{[subst -nocommand {set $vn \$v}] \}
uplevel 1 public method get$vn \{\} \{[subst -nocommand {return $$vn}]\}
}
}
itcl::class BarBar {
eval makegetset {foo 9 foot 2 frob 6}
constructor {} {}
}
set o [BarBar #auto]
puts "In $o foo is [$o getfoo] foot is [$o getfoot] and frob [$o getfrob]"
$o setfoo 355
$o getfoo
