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Public Variable Configuration
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Declaring and Using
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Initialization of Public
Type Checker
You can use a
type ckecker procedure
to check whether the user
has supplied a value of the correct type for a public variable. The
type checker is specified in the
-configspec
section of the
class declaration after the default value. The following code
specifies the type checker procedure
CheckDirection
for the
-direction
variable:
-configspec {
{-direction direction Direction e CheckDirection}
{-state state State normal}
}
...
}
proc CheckDirection {dir} {
if {[lsearch {n s w e} $dir] != -1} {
return $dir
} else {
error "wrong direction value $
$"$dir$
$""
}
Notice that no type checker has been specified for the
-state
variable and thus its value will not be checked.
If a type checker procedure is specified for a public variable, this
procedure will be called once the value of a public variable is
determined by the three steps mentioned above.
http://tix.sourceforge.net
http://tix.sourceforge.net
