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diff --git a/doc/define.n b/doc/define.n new file mode 100644 index 0000000..a1a92bf --- /dev/null +++ b/doc/define.n @@ -0,0 +1,269 @@ +'\" +'\" 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: define.n,v 1.1 2008/05/31 11:42:12 dkf Exp $ +'\" +.so man.macros +.TH define n 0.3 TclOO "TclOO Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +oo::define, oo::objdefine \- define and configure classes and objects +.SH SYNOPSIS +.nf +package require TclOO + +\fBoo::define\fI class defScript\fR +\fBoo::define\fI class subcommand arg\fR ?\fIarg ...\fR? +\fBoo::objdefine\fI object defScript\fR +\fBoo::objdefine\fI object subcommand arg\fR ?\fIarg ...\fR? +.fi +.BE + +.SH DESCRIPTION +The \fBoo::define\fR command is used to control the configuration of classes, +and the \fBoo::objdefine\fR command is used to control the configuration of +objects (including classes as instance objects), with the configuration being +applied to the entity named in the \fIclass\fR or the \fIobject\fR argument. +Configuring a class also updates the +configuration of all subclasses of the class and all objects that are +instances of that class or which mix it in (as modified by any per-instance +configuration). The way in which the configuration is done is controlled by +either the \fIdefScript\fR argument or by the \fIsubcommand\fR and following +\fIarg\fR arguments; when the second is present, it is exactly as if all the +arguments from \fIsubcommand\fR onwards are made into a list and that list is +used as the \fIdefScript\fR argument. +.SS "CONFIGURING CLASSES" +.PP +The following commands are supported in the \fIdefScript\fR for +\fBoo::define\fR, each of which may also be used in the \fIsubcommand\fR form: +.TP +\fBconstructor\fI argList bodyScript\fR +. +This creates or updates the constructor for a class. The formal arguments to +the constructor (defined using the same format as for the Tcl \fBproc\fR +command) will be \fIargList\fR, and the body of the constructor will be +\fIbodyScript\fR. When the body of the constructor is evaluated, the current +namespace of the constructor will be a namespace that is unique to the object +being constructed. Within the constructor, the \fBnext\fR command should be +used to call the superclasses' constructors. If \fIbodyScript\fR is the empty +string, the constructor will be deleted. +.TP +\fBdeletemethod\fI name\fR ?\fIname ...\fR +. +This deletes each of the methods called \fIname\fR from a class. The methods +must have previously existed in that class. Does not affect the superclasses +of the class, nor does it affect the subclasses or instances of the class +(except when they have a call chain through the class being modified). +.TP +\fBdestructor\fI bodyScript\fR +. +This creates or updates the destructor for a class. Destructors take no +arguments, and the body of the destructor will be \fIbodyScript\fR. The +destructor is called when objects of the class are deleted, and when called +will have the object's unique namespace as the current namespace. Destructors +should use the \fBnext\fR command to call the superclasses' destructors. Note +that destructors are not called in all situations (e.g. if the interpreter is +destroyed). If \fIbodyScript\fR is the empty string, the destructor will be +deleted. +.RS +Note that errors during the evaluation of a destructor \fIare not returned\fR +to the code that causes the destruction of an object. Instead, they are passed +to the currently-defined \fBbgerror\fR handler. +.RE +.TP +\fBexport\fI name \fR?\fIname ...\fR? +. +This arranges for each of the named methods, \fIname\fR, to be exported +(i.e. usable outside an instance through the instance object's command) by the +class being defined. Note that the methods themselves may be actually defined +by a superclass; subclass exports override superclass visibility, and may in +turn be overridden by instances. +.TP +\fBfilter\fR ?\fImethodName ...\fR? +. +This sets or updates the list of method names that are used to guard whether a +method call to instances of the class may be called and what the method's +results are. Each \fImethodName\fR names a single filtering method (which may +be exposed or not exposed); it is not an error for a non-existent method to be +named since they may be defined by subclasses. If no \fImethodName\fR +arguments are present, the list of filter names is set to empty. +.TP +\fBforward\fI name cmdName \fR?\fIarg ...\fR? +. +This creates or updates a forwarded method called \fIname\fR. The method +is defined be forwarded to the command called \fIcmdName\fR, with additional +arguments, \fIarg\fR etc., added before those arguments specified by the +caller of the method. Forwarded methods should be deleted using the +\fBmethod\fR subcommand. The method will be exported if \fIname\fR starts with +a lower-case letter, and non-exported otherwise. +.TP +\fBmethod\fI name argList bodyScript\fR +. +This creates, updates or deletes a method. The name of the method is +\fIname\fR, the formal arguments to the method (defined using the same format +as for the Tcl \fBproc\fR command) will be \fIargList\fR, and the body of the +method will be \fIbodyScript\fR. When the body of the method is evaluated, the +current namespace of the method will be a namespace that is unique to the +current object. The method will be exported if \fIname\fR starts with a +lower-case letter, and non-exported otherwise; this behavior can be overridden +via \fBexport\fR and \fBunexport\fR. +.TP +\fBmixin\fR ?\fIclassName ...\fR? +. +This sets or updates the list of additional classes that are to be mixed into +all the instances of the class being defined. Each \fIclassName\fR argument +names a single class that is to be mixed in; if no classes are present, the +list of mixed-in classes is set to be empty. +.TP +\fBrenamemethod\fI fromName toName\fR +. +This renames the method called \fIfromName\fR in a class to \fItoName\fR. The +method must have previously existed in the class, and \fItoName\fR must not +previously refer to a method in that class. Does not affect the superclasses +of the class, nor does it affect the subclasses or instances of the class +(except when they have a call chain through the class being modified). Does +not change the export status of the method; if it was exported before, it will +be afterwards. +.TP +\fBself\fI subcommand arg ...\fR +.TP +\fBself\fI script\fR +. +This command is equivalent to calling \fBoo::objdefine\fR on the class being +defined (see \fBCONFIGURING OBJECTS\fR below for a description of the +supported values of \fIsubcommand\fR). It follows the same general pattern of +argument handling as the \fBoo::define\fR and \fBoo::objdefine\fR commands, +and +.QW "\fBoo::define \fIcls \fBself \fIsubcommand ...\fR" +operates identically to +.QW "\fBoo::objdefine \fIcls subcommand ...\fR" . +.TP +\fBsuperclass\fI className \fR?\fIclassName ...\fR? +. +This allows the alteration of the superclasses of the class being defined. +Each \fIclassName\fR argument names one class that is to be a superclass of +the defined class. Note that objects must not be changed from being classes to +being non-classes or vice-versa. +.TP +\fBunexport\fI name \fR?\fIname ...\fR? +. +This arranges for each of the named methods, \fIname\fR, to be not exported +(i.e. not usable outside the instance through the instance object's command, +but instead just through the \fBmy\fR command visible in each object's +context) by the class being defined. Note that the methods themselves may be +actually defined by a superclass; subclass unexports override superclass +visibility, and may be overridden by instance unexports. +.SS "CONFIGURING OBJECTS" +.PP +The following commands are supported in the \fIdefScript\fR for +\fBoo::objdefine\fR, each of which may also be used in the \fIsubcommand\fR +form: +.TP +\fBclass\fI className\fR +. +This allows the class of an object to be changed after creation. Note that the +class's constructors are not called when this is done, and so the object may +well be in an inconsistent state unless additional configuration work is done. +.TP +\fBdeletemethod\fI name\fR ?\fIname ...\fR +. +This deletes each of the methods called \fIname\fR from an object. The methods +must have previously existed in that object. Does not affect the classes that +the object is an instance of. +.TP +\fBexport\fI name \fR?\fIname ...\fR? +. +This arranges for each of the named methods, \fIname\fR, to be exported +(i.e. usable outside the object through the object's command) by the object +being defined. Note that the methods themselves may be actually defined by a +class or superclass; object exports override class visibility. +.TP +\fBfilter\fR ?\fImethodName ...\fR? +. +This sets or updates the list of method names that are used to guard whether a +method call to the object may be called and what the method's results are. +Each \fImethodName\fR names a single filtering method (which may be exposed or +not exposed); it is not an error for a non-existent method to be named. If no +\fImethodName\fR arguments are present, the list of filter names is set to +empty. Note that the actual list of filters also depends on the filters set +upon any classes that the object is an instance of. +.TP +\fBforward\fI name cmdName \fR?\fIarg ...\fR? +. +This creates or updates a forwarded object method called \fIname\fR. The +method is defined be forwarded to the command called \fIcmdName\fR, with +additional arguments, \fIarg\fR etc., added before those arguments specified +by the caller of the method. Forwarded methods should be deleted using the +\fBmethod\fR subcommand. The method will be exported if \fIname\fR starts with +a lower-case letter, and non-exported otherwise. +.TP +\fBmethod\fI name argList bodyScript\fR +. +This creates, updates or deletes an object method. The name of the method is +\fIname\fR, the formal arguments to the method (defined using the same format +as for the Tcl \fBproc\fR command) will be \fIargList\fR, and the body of the +method will be \fIbodyScript\fR. When the body of the method is evaluated, the +current namespace of the method will be a namespace that is unique to the +object. The method will be exported if \fIname\fR starts with a lower-case +letter, and non-exported otherwise. +.TP +\fBmixin\fR ?\fIclassName ...\fR? +. +This sets or updates a per-object list of additional classes that are to be +mixed into the object. Each argument, \fIclassName\fR, names a single class +that is to be mixed in; if no classes are present, the list of mixed-in +classes is set to be empty. +.TP +\fBrenamemethod\fI fromName toName\fR +. +This renames the method called \fIfromName\fR in an object to \fItoName\fR. +The method must have previously existed in the object, and \fItoName\fR must +not previously refer to a method in that object. Does not affect the classes +that the object is an instance of. Does not change the export status of the +method; if it was exported before, it will be afterwards. +.TP +\fBunexport\fI name \fR?\fIname ...\fR? +. +This arranges for each of the named methods, \fIname\fR, to be not exported +(i.e. not usable outside the object through the object's command, but instead +just through the \fBmy\fR command visible in the object's context) by the +object being defined. Note that the methods themselves may be actually defined +by a class; instance unexports override class visibility. +.SH EXAMPLES +This example demonstrates how to use both forms of the \fBoo::define\fR and +\fBoo::objdefine\fR commands (they work in the same way), as well as +illustrating four of the subcommands of them. +.PP +.CS +oo::class create c +c create o +\fBoo::define\fR c \fBmethod\fR foo {} { + puts "world" +} +\fBoo::objdefine\fR o { + \fBmethod\fR bar {} { + my Foo "hello " + my foo + } + \fBforward\fR Foo ::puts -nonewline + \fBunexport\fR foo +} +o bar \fI\(-> prints "hello world"\fR +o foo \fI\(-> error "unknown method foo"\fR +o Foo Bar \fI\(-> error "unknown method Foo"\fR +\fBoo::objdefine\fR o \fBrenamemethod\fR bar lollipop +o lollipop \fI\(-> prints "hello world"\fR +.CE +.SH "SEE ALSO" +next(n), oo::class(n), oo::object(n) +.SH KEYWORDS +class, definition, method, object + +.\" Local variables: +.\" mode: nroff +.\" fill-column: 78 +.\" End: |