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 BOOK Tcl/Tk Tools: contains an out of date tutorial for itcl.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.

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It does not have a parameter corresponding to arguments.

Tcl/Tk Tutorial

The above stems from the fact that EFT does not really reflect a real object. This facilitates testing of the objects prior to integration into the application. The created objects are Tcl commands and as such can be created in any namespace. Smith is suspected of being up to his old tricks again and we need tutroial monitor his accounts and log all activity.

Filter methods are always placed at the front of the method chain so that can be a factor as well in deciding to use tutorisl filter.

This ability to define object-specific methods can be very useful. Let us rework our previous example.

Object Oriented Programming in Tcl

The general thinking is that such classes are better modeled as mixins. An object of a class is created by invoking one of two built-in methods on the class itself. In that case we could have defined the Log command as follows:.


Methods that begin with a lower case letter are exported by default.

In the case the current method is the last in the chain, an empty list is returned. Constructors and destructors There is one final thing we need to do before we can start banking operations and that is to provide some means to initialize an Account object when it is created and perform any required clean up when it is destroyed. Some of these are common to all account types while others are unique. Some general rules are.

Constructors and destructors are also chained. For these reasons, mixins seemed a better choice in our design aside from the fact that we needed some example to illustrate mixins. This defines the data members for the class as per-object variables. Be careful when using multiple superclass statements as the tutorila declarations are overwritten by default. The output shows the method chain so we can see for example that the filter methods are first in line.

Moreover, since Tcl is a dynamic language, we would have to make sure we do that any time new methods were defined for the object or any ancestor and mixin.

Using multiple mixins A class or object may have multiple classes mixed in.


Now let us define another class that also uses the mixin. Let us go back to our banking model. Enumerating methods The list of methods implemented by a class or object can be retrieved through info class methods and info object methods respectively. This is done with the command next which invokes the next method in the which in this case is the superclass method with the same name as the current method.

Thus the above command will not show the variable Balance as that was defined in the base class Accountnot in SavingsAccount.

It is more like a set of features or capabilities that accounts have. Destructors behave in a similar fashion. Conversely, the info class subclasses will return the classes directly tytorial from the specified class. This can be useful for example when namespaces are used to segregate objects. Because one of its goal is to provide the required infrastructure for additional OO system to be built on top, TclOO itck a wide variety of capabilities that sometimes overlap in their effect.

What does the method chain look like for a method that is not defined for the object? So far so good. Views Read Edit View history.