ITCL TUTORIAL PDF
Abbreviated form of incr Tcl, iTcl is the term used for referring to the object- oriented extensions meant for Tcl programming language. Let’s learn more about . The name is often written as “itcl” as that contains no metacharacters (i.e., space or brackets). BOOK Tcl/Tk Tools: contains an out of date tutorial for itcl. A more tutorial introduction is presented in the paper included with this distribution. See the class command for more details on creating and using classes.
|Published (Last):||19 June 2004|
|PDF File Size:||17.32 Mb|
|ePub File Size:||4.2 Mb|
|Price:||Free* [*Free Regsitration Required]|
However, there is no requirement that filter methods must be private.
This is-a relation is key when deciding whether to use inheritance or some other facility such as mix-ins. The first command returns an empty list because no variables were declared through variable for that object. The iTcl implementations exist both in the form of a standalone independent language having its own interpreter as well as a package which can be dynamically loaded by any Tcl application.
Note this is not the same as the class the object belongs to as the example below shows. Note the optional form of the oo:: The implementation of unknown looks like.
Rather, the constructor method is automatically run when an object is created.
The former is returned by the self object command, which can also be called as simply self. As one might expect, there is also a command, info class mixins for listing mixins. Throughout this chapter we have seen that when a method is invoked on an object, the code implementing the method for that object may come from several different places – the object, its class or an ancestor, a mixin, forwarded methods, filters or even unknown method handlers.
The properties and methods exported from a COM component are not always known beforehand and in fact can be dynamically modified. Tutrial members do not have to be declared using variable in a class definition script. Creating an object An object of a class is created by invoking one of two built-in methods on the class itself. It all works now because we only call next if there is in fact a next method to call. Smith can withdraw money freely from his account. It does not affect methods defined utcl the class so the original UpdateBalance will still be in place and will no longer be overridden.
Object-specific methods Let us illustrate with our banking example. A method may need to know command name of the object. Enumerating objects The info class instances command returns a list of objects belonging to the specified class. No, Citibank cannot run its operations based on our framework but it suffices for our illustrative purposes.
Note -clear tutirial to clear any currently defined filters.
Using next would not work because the parent class constructors do not take the same arguments. Methods are defined through the method command which, like variableis executed as part of a class definition script. Obj81 saving account data to database. They are not explicitly invoked by name. Method chain for unknown methods What does the method chain look like for a method that is not defined for the object? Not directly inheriting or modifying the CheckingAccount class was a no-brainer for obvious reasons.
itcl (n) – Linux Man Pages
So tutorkal come up with a new type of account, a Cash Management Account CMAwhich combines the features of the checking and brokerage accounts. Conversely, method overrides, such as in our account freeze example, could be replaced by filters. Inspecting method chains within method contexts Within a method context, the command self call returns more or less the same information for the current object as info object call. We reiterate that not every method tutoriaal the chain is automatically invoked.
About iTcl or incr Tcl
Let us create a itl, Accountthat models a banking account. Imagine our banking system had the requirement that individual accounts can be frozen based on an order from the tax authorities. They need to be brought into scope with the my variable statement. At the same time it is a class and hence must be an instance of oo:: The create method creates an object with a specific name.
This chapter describes Tcl features that support object oriented programming.