NAME
xowish - Graphical shell containing object-oriented scripting language
XOTcl
SYNOPSIS
xowish ?fileName arg arg ...?
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DESCRIPTION
xowish is a shell-like application that reads XOTcl commands from its
standard input or from a file and evaluates them. In addition to
xotclsh it provides graphical user interface support for TK widgets.
XOTcl (XOTcl, pronounced exotickle) is an object-oriented scripting
language based on MIT’s OTcl. It is intended as a value added
replacement for OTcl.
Scripting languages, like Tcl, are designed for glueing components
together, provide features like dynamic extensibility and dynamic
typing with automatic conversion, that make them well suited for rapid
application development.
The basic object system of XOTcl is adopted from OTcl. The object
system enables us to define objects, classes, and meta-classes. Classes
are special objects with the purpose of managing other objects.
‘‘Managing’’ means that a class controls the creation and destruction
of its instances and that it contains a repository of methods
accessible for the instances. Every object may be enhanced with object-
specific methods. XOTcl supports single and multiple inheritance. All
relationships in XOTcl, including class and superclass relationships,
are completely dynamic and can be introspected. Through method chaining
without explicit naming of the intended method, ambiguities in name
resolution of methods are avoided. This way a shadowed method can be
‘‘mixed into’’ the execution of the current method.
XOTcl combines the ideas of scripting and object-orientation in a way
that preserves the benefits of both of them. It is equipped with
several new language functionalities that help building and managing
complex systems. We added the following support:
Dynamic Object Aggregations, to provide dynamic aggregations through
nested namespaces (objects).
Nested Classes, to reduce the interference of independently developed
program structures.
Assertions, to reduce the interface and the reliability problems caused
by dynamic typing and, therefore, to ease the combination of many
components.
Meta-data, to enhance self-documentation of objects and classes.
Per-object mixins, as a means to improve flexibility of mixin methods
by giving an object access to several different supplemental classes,
which may be changed dynamically.
Per-class mixins, as a means to improve flexibility of mixin methods to
a class, all instances of the class have access to the mixed in methods
like for multiple inheritance, but without the need of intersection
classes.
Filters as a means of abstractions over method invocations to implement
large program structures, like design patterns.
Dynamic Component Loading XOTcl integrates the Tcl package loading with
architectrual support for integration with object-oriented constructs.
Moreover, it provides tracking/tracing of component loading.
KEYWORDS
argument, interpreter, prompt, script file, shell