This page describes an upcoming enhancement to TclOO: Property tracking. Please stay tuned.
The concept: Adding information that is tracked by class that allows the developer to embed data inside of classes
The following keywords will be added to oo::define:
Set a property from the class definition.
This method allows access to this class. Arguments that follow determine exactly what's done.
There will be an equivalent lookup based on objects.
This method provides objects access to the property database of their class. (Without the hassle of having to look up their class.) At present, it is read only.
This system was originally intended to provide a Tk option-like database for TclOO objects.
# Dump the entire option dictionary set option_dict [info object [self] property get option]
# Access a list of options set option_list [info object [self] property list option]
# Check if an option exists set exists [info object [self] property exists option color]
# Get the default value for color set color [info object [self] property getnull option color default]
oo::define oo::class_withopts { constructor args { my InitializePublic {*}$args } method InitializePublic args { my variable config set optiondict [info object [self] property get option] # Populate config() with defaults foreach {field info} $optiondict { if {[info exists config($field)]} continue if {[dict exists $optiondict $field]} { set config($field) [dict get $optiondict default] } else { set config($field) {} } } foreach {field value} $args { set key [string trimleft $key -] if {![dict exists $optiondict $key]} { error "Bad option: $key, valid: [lsort -dictionary [dict keys $optiondict]]" } set config($field) $value } } method configure args { my variable config set triggers {} set optiondict [info object [self] property get option] foreach {key value} $args { set key [string trimleft $key -] if {![dict exists $optiondict $key]} { error "Bad option: $key, valid: [lsort -dictionary [dict keys $optiondict]]" } } foreach {key value} $args { set key [string trimleft $key -] if {$value != $config($key)} { set config($key) $value if {[dict exists $optiondict $field trigger]} { lappend triggers $field $value [dict get $optiondict $field set-script] } } } foreach {field value script] $triggers { eval [string map [list %object% [self] %self% [self] %field% $field %value% $value] $script] } } method cget field { set field [string trimleft $field -] if {![info object property [self] exists option $field]} { error "Invalid option $field, Valid [info option property [self] list option]" } my variable config return $config($field) } }