diff options
author | dkf <donal.k.fellows@manchester.ac.uk> | 2008-05-31 11:41:59 (GMT) |
---|---|---|
committer | dkf <donal.k.fellows@manchester.ac.uk> | 2008-05-31 11:41:59 (GMT) |
commit | 5b6e0993e188fd16bbb2ec7f54b8b0c7be873629 (patch) | |
tree | b68d9c4cbdbd0775c0419a152b70758bde998ca0 /doc/class.n | |
parent | 032cdb06a8056b84ec16eaace0fc84044c95899a (diff) | |
download | tcl-5b6e0993e188fd16bbb2ec7f54b8b0c7be873629.zip tcl-5b6e0993e188fd16bbb2ec7f54b8b0c7be873629.tar.gz tcl-5b6e0993e188fd16bbb2ec7f54b8b0c7be873629.tar.bz2 |
Implementation of TIP #257. Incomplete due to missing Win build support.
Diffstat (limited to 'doc/class.n')
-rw-r--r-- | doc/class.n | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/doc/class.n b/doc/class.n new file mode 100644 index 0000000..02dfc46 --- /dev/null +++ b/doc/class.n @@ -0,0 +1,126 @@ +'\" +'\" Copyright (c) 2007 Donal K. Fellows +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +'\" RCS: @(#) $Id: class.n,v 1.1 2008/05/31 11:42:06 dkf Exp $ +'\" +.so man.macros +.TH class n 0.1 TclOO "TclOO Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +oo::class \- class of all classes +.SH SYNOPSIS +.nf +package require TclOO + +\fBoo::class\fI method \fR?\fIarg ...\fR? +.fi +.SH "CLASS HIERARCHY" +.nf +\fBoo::object\fR + \(-> \fBoo::class\fR +.fi +.BE + +.SH DESCRIPTION +The \fBoo::class\fR class is the class of all classes; every class is an +instance of this class, which is consequently an instance of itself. This +class is a subclass of \fBoo::object\fR, so every class is also an object. +Additional metaclasses (i.e. classes of classes) can be defined if necessary +by subclassing \fBoo::class\fR. Note that the \fBoo::class\fR object hides the +\fBnew\fR method on itself, so new classes should always be made using the +\fBcreate\fR method. +.SS CONSTRUCTOR +The constructor of the \fBoo::class\fR class takes an optional argument which, +if present, is sent to the \fBoo::define\fR command (along with the name of +the newly-created class) to allow the class to be conveniently configured at +creation time. +.SS DESTRUCTOR +The \fBoo::class\fR class does not define an explicit destructor. However, +when a class is destroyed, all its subclasses and instances are also +destroyed, along with all objects that it has been mixed into. +.SS "EXPORTED METHODS" +.TP +\fIcls \fBcreate \fIname \fR?\fIarg ...\fR? +. +This creates a new instance of the class \fIcls\fR called \fIname\fR (which is +resolved within the calling context's namespace if not fully qualified), +passing the arguments, \fIarg ...\fR, to the constructor, and (if that returns +a successful result) returning the fully qualified name of the created object +(the result of the constructor is ignored). If the constructor fails (i.e. +returns a non-OK result) then the object is destroyed and the error message is +the result of this method call. +.TP +\fIcls \fBnew \fR?\fIarg ...\fR? +. +This creates a new instance of the class \fIcls\fR with a new unique name, +passing the arguments, \fIarg ...\fR, to the constructor, and (if that returns +a successful result) returning the fully qualified name of the created object +(the result of the constructor is ignored). If the constructor fails (i.e. +returns a non-OK result) then the object is destroyed and the error message is +the result of this method call. Note that this method is not exported by the +\fBoo::class\fR object itself, so classes should not be created using this +method. +.SS "NON-EXPORTED METHODS" +The \fBoo::class\fR class supports the following non-exported methods: +.TP +\fIobj \fBcreateWithNamespace\fI name nsName\fR ?\fIarg ...\fR? +. +This creates a new instance of the class \fIcls\fR called \fIname\fR (which is +resolved within the calling context's namespace if not fully qualified), +passing the arguments, \fIarg ...\fR, to the constructor, and (if that returns +a successful result) returning the fully qualified name of the created object +(the result of the constructor is ignored). The name of the instance's +internal namespace will be \fInsName\fR unless that namespace already exists +(when an arbitrary name will be chosen instead). If the constructor fails +(i.e. returns a non-OK result) then the object is destroyed and the error +message is the result of this method call. +.SH EXAMPLES +This example defines a simple class hierarchy and creates a new instance of +it. It then invokes a method of the object before destroying the hierarchy and +showing that the destruction is transitive. +.CS +\fBoo::class create\fR fruit { + method eat {} { + puts "yummy!" + } +} +\fBoo::class create\fR banana { + superclass fruit + constructor {} { + my variable peeled + set peeled 0 + } + method peel {} { + my variable peeled + set peeled 1 + puts "skin now off" + } + method edible? {} { + my variable peeled + return $peeled + } + method eat {} { + if {![my edible?]} { + my peel + } + next + } +} +set b [banana \fBnew\fR] +$b eat \fI\(-> prints "skin now off" and "yummy!"\fR +fruit destroy +$b eat \fI\(-> error "unknown command"\fR +.CE +.SH "SEE ALSO" +oo::define(n), oo::object(n) +.SH KEYWORDS +class, metaclass, object + +.\" Local variables: +.\" mode: nroff +.\" fill-column: 78 +.\" End: |