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# stooop(n) 4.4.2 tcllib "Simple Tcl Only Object Oriented Programming"

## Name

stooop - Object oriented extension.

## Synopsis

- package require Tcl 8.5 9
- package require stooop ?4.4.2?

- ::stooop::class name body
- ::stooop::new class ?arg arg ...?
- ::stooop::delete object ?object ...?
- ::stooop::virtual proc name {this ?arg arg ...?} ?body?
- ::stooop::classof object
- ::stooop::new object
- ::stooop::printObjects ?pattern?
- ::stooop::record
- ::stooop::report ?pattern?

## Description

This package provides commands to extend Tcl in an object oriented manner, using a familiar C++ like syntax and behaviour. Stooop only introduces a few new commands: class, new, delete, virtual and classof. Along with a few coding conventions, that is basically all you need to know to use stooop. Stooop is meant to be as simple to use as possible.

This manual is very succinct and is to be used as a quick reminder for the programmer, who should have read the thorough stooop_man.html HTML documentation at this point.

::stooop::class name body

  This command creates a class. The body, similar in contents to a Tcl namespace (which a class actually also is), contains member procedure definitions. Member procedures can also be defined outside the class body, by prefixing their name with class::, as you would proceed with namespace procedures.

  proc class {this ?arg arg ...?} ?base {?arg arg ...?} ...? body

    This is the constructor procedure for the class. It is invoked following a new invocation on the class. It must have the same name as the class and a first argument named this. Any number of base classes specifications, including arguments to be passed to their constructor, are allowed before the actual body of the procedure.

  proc ~class {this} body

    This is the destructor procedure for the class. It is invoked following a delete invocation. Its name must be the concatenation of a single ~ character followed by the class name (as in C++). It must have a single argument named this.

  proc name {this ?arg arg ...?} body

    This is a member procedure of the class, as its first argument is named this. It allows a simple access of member data for the object referenced by this inside the procedure. For example:

           set ($this,data) 0

  proc name {?arg arg ...?} body

    This is a static (as in C++) member procedure of the class, as its first argument is not named this. Static (global) class data can be accessed as in:

           set (data) 0

  proc class {this copy} body

    This is the optional copy procedure for the class. It must have the same name as the class and exactly 2 arguments named this and copy. It is invoked following a new invocation on an existing object of the class.

::stooop::new class ?arg arg ...?

  This command is used to create an object. The first argument is the class name and is followed by the arguments needed by the corresponding class constructor. A unique identifier for the object just created is returned.

::stooop::delete object ?object ...?

  This command is used to delete one or several objects. It takes one or more object identifiers as argument(s).

::stooop::virtual proc name {this ?arg arg ...?} ?body?

  The virtual specifier may be used on member procedures to achieve dynamic binding. A procedure in a base class can then be redefined (overloaded) in the derived class(es). If the base class procedure is invoked on an object, it is actually the derived class procedure which is invoked, if it exists. If the base class procedure has no body, then it is considered to be a pure virtual and the derived class procedure is always invoked.

::stooop::classof object

  This command returns the class of the existing object passed as single parameter.

::stooop::new object

  This command is used to create an object by copying an existing object. The copy constructor of the corresponding class is invoked if it exists, otherwise a simple copy of the copied object data members is performed.

## DEBUGGING

Environment variables
  STOOOPCHECKDATA

    Setting this variable to any true value will cause stooop to check for invalid member or class data access.

  STOOOPCHECKPROCEDURES

    Setting this variable to any true value will cause stooop to check for invalid member procedure arguments and pure interface classes instanciation.

  STOOOPCHECKALL

    Setting this variable to any true value will cause stooop to activate both procedure and data member checking.

  STOOOPCHECKOBJECTS

    Setting this variable to any true value will cause stooop to activate object checking. The following stooop namespace procedures then become available for debugging: printObjects, record and report.

  STOOOPTRACEPROCEDURES

    Setting this environment variable to either stdout, stderr or a file name, activates procedure tracing. The stooop library will then output to the specified channel 1 line of informational text for each member procedure invocation.

  STOOOPTRACEPROCEDURESFORMAT

    Defines the trace procedures output format. Defaults to "class: %C, procedure: %p, object: %O, arguments: %a".

  STOOOPTRACEDATA

    Setting this environment variable to either stdout, stderr or a file name, activates data tracing. The stooop library will then output to the specified channel 1 line of informational text for each member data access.

  STOOOPTRACEDATAFORMAT

    Defines the trace data output format. Defaults to "class: %C, procedure: %p, array: %A, object: %O, member: %m, operation: %o, value: %v".

  STOOOPTRACEDATAOPERATIONS

    When tracing data output, by default, all read, write and unsetting accesses are reported, but the user can set this variable to any combination of the letters r, w, and u for more specific tracing (please refer to the trace Tcl manual page for more information).

  STOOOPTRACEALL

    Setting this environment variable to either stdout, stderr or a file name, enables both procedure and data tracing.

::stooop::printObjects ?pattern?

  Prints an ordered list of existing objects, in creation order, oldest first. Each output line contains the class name, object identifier and the procedure within which the creation occurred. The optional pattern argument (as in the Tcl string match command) can be used to limit the output to matching class names.

::stooop::record

  When invoked, a snapshot of all existing stooop objects is taken. Reporting can then be used at a later time to see which objects were created or deleted in the interval.

::stooop::report ?pattern?

  Prints the created and deleted objects since the ::stooop::record procedure was invoked last. If present, the pattern argument limits the output to matching class names.

## EXAMPLES

Please see the full HTML documentation in stooop_man.html.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category stooop of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## Keywords

C++, class, object, object oriented

## Category

Programming tools