# $Id: langRef.xotcl,v 1.18 2007/09/05 19:09:22 neumann Exp $ package provide XOTcl-langRef 1.5.5 package require XOTcl @ @File { description { XOTcl language reference. Describes predefined objects and classes. } "predefined primitives" { XOTcl contains the following predefined primitives (Tcl commands):
<@tt>self<@/tt>
computes callstack related information. It can be used in the following ways: <@UL> <@LI><@TT>self - returns the name of the object, which is currently in execution. If it is called from outside of a proc, it returns the error message ``<@TT>Can't find self''. <@LI><@TT>self class - the self command with a given argument <@TT>class returns the name of the class, which holds the currently executing instproc. Note, that this may be different to the class of the current object. If it is called from a proc it returns an empty string. <@LI><@TT>self proc - the self command with a given argument <@TT>proc returns the name of the currently executing proc or instproc. <@li><@TT>self callingclass: Returns class name of the class that has called the executing method. <@li><@TT>self callingobject: Returns object name of the object that has called the executing method. <@li><@TT>self callingproc: Returns proc name of the method that has called the executing method. <@li><@TT>self calledclass: Returns class name of the class that holds the target proc (in mixins and filters). <@li><@TT>self calledproc: Returns method name of the target proc (only applicable in a filter). <@li><@TT>self isnextcall: Return 1 if this method was invoked via next, otherwise 0 <@li><@TT>self next: Return the "next" method on the precedence path as a string. <@li><@TT>self filterreg: In a filter: returns the name of the object/class on which the filter is registered. Returns either 'objName filter filterName' or 'className instfilter filterName'. <@li><@TT>self callinglevel: Returns the calling level, from where the actual proc was called from. Intermediary next calls are ignored in this computation. The level is returned in a form it can be used as first argument in <@TT>uplevel or <@TT>upvar. <@li><@TT>self activelevel: Returns the level, from where the actual proc was invoked from. This might be the calling level or a next call, whatever is higher in the stack. The level is returned in a form it can be used as first argument in <@TT>uplevel or <@TT>upvar. <@/UL> <@/p>
<@tt>my methodName<@/tt>
is a short form for <@tt>[self] methodName and can only be called in a context of an instproc or an method specific proc. It allows certain optimizations and shorter to write. <@/p><@p> <@tt>next <@/tt>
invokes the next shadowed (same-named) method on the precedence path and returns its result. If <@tt>next is called without arguments, the arguments of the current method are passed through the called method. If <@tt>next is invoked with the flag <@tt>--noArgs, the shadowed method is called without arguments. If other arguments are specified for next, these will be used for the call. <@/dd>
<@tt>myvar varName
returns the fully qualified variable name of the specified variable.

<@tt>myproc methodName ?args?
calls the specified XOTcl method without the need of using "<@tt>[list [self] methodName ...]".

<@tt>::xotcl::alias class|obj methodName ?-objscope? ?-per-object? cmdName
can be used to register a predefined C-implemented Tcl command as method <@tt>methodName. The option <@tt>-objscope has the same meaning as for forwarder (instance variables of the calling object appear in the local scope of the Tcl command), <@tt>-per-object has the same meaning as for the method <@tt>method (when used on a class, the method is registered for the class object only, but not for the instances). This command can be used to bootstrap xotcl (when e.g. no methods are available).

::xotcl::configure filter ?on|off?<@/tt>
allows to turn on or off filters globally for the current interpreter. By default, the filter state is turned off. This function returns the old filter state. This function is needed for the serializer that is intended to serialize the objects classes independent of filter settings.

<@tt>::xotcl::configure softrecreate ?on|off?<@/tt>
allows to control what should happen, when an object / a class is recreated. Per default it is set off, which means that the object/class is destroyed and all relations (e.g. subclass/superclass) to other objects/classes are destroyed as well. If <@tt>softrecreate is set, the object is reseted, but not destroyed, the relations are kept. This is important, when e.g. reloading a file with class definitions (e.g. when used in OpenACS with file watching and reloading). With <@tt>softrecreate set, it is not necessary to recreate dependent subclasses etc.
Example: e.g. there is a class hierarchy A <- B <- C Without <@tt>softrecreate set, a reload of B means first a destroy of B, leading to A <- C, and instances of B are re-classed to ::xotcl::Object. When <@tt>softrecreate is set, the structure remains unchanged.
} date { $Date: 2007/09/05 19:09:22 $ } } ## ## Object methods ## @ Class Object { description { This class holds the pre-defined methods available for all XOTcl objects. All these methods are also available on classes. } } @ Object instproc abstract { methtype "instproc or proc" methodName "name of abstract method" arglist "arguments" } { Description { Specify an abstract method for class/object with arguments. An abstract method specifies an interface and returns an error, if it is invoked directly. Sub-classes or mixins have to override it. } return "error" } @ Object instproc append { varName "name of variable" args "arguments to append" } { Description { Append all of the value arguments to the current value of variable varName. Wrapper to the same named Tcl command (see documentation of Tcl command with the same name for details). } return "empty string" } @ Object instproc array { opt "array option" array "array name" ?args? "args of the option" } { Description { This method performs one of several operations on the variable given by arrayName. It is a wrapper to the same named Tcl command (see documentation of Tcl command with the same name for details). } return "diverse results" } @ Object instproc autoname { ?<-instance>|<-reset>? "Optional modifiers: <@br> '-instance' makes the autoname start with a small letter.<@br> '-reset' resets the autoname index to 0." name "base name of the autoname"} { Description { autoname creates an automatically assigned name. It is constructed from the base name plus an index, that is incremented for each usage. E.g.: <@pre class='code'> $obj autoname a produces a0, a1, a2, ... Autonames may have format strings as in the Tcl 'format' command. E.g.: <@pre class='code'> $obj autoname a%06d produces a000000, a000001, a000002, ... } return "newly constructed autoname value" } @ Object instproc check { options "none, one or more of: (?all? ?pre? ?post? ?invar? ?instinvar?)" } { Description { Turn on/off assertion checking. Options argument is the list of assertions, that should be checked on the object automatically. Per default assertion checking is turned off. Examples: <@pre class='code'> o check {}; <@it># turn off assertion checking on object o o check all; <@it># turn on all assertion checks on object o o check {pre post}; <@it># only check pre/post assertions <@a href="#Object-info">info check introspects check options. } return "empty string" } @ Object instproc class { newClass "?new class?" } { Description { Changes the class of an object dynamically to <@tt>newClass. The method returns the current value of class, when it is called without arguments. } return "if <@tt>newClass is not specified return class, otherwise empty" } @ Object instproc cleanup { ?args? "Arbitrary arguments passed to cleanup" } { Description { Resets an object or class into an initial state, as after construction. Called during recreation process by the method 'recreate' } return "empty string" } @ Object instproc configure { ?args? "'-' method calls" } { Description { Calls the '-' (dash) methods. I.e. evaluates arguments and calls everything starting with '-' (and not having a digit a second char) as a method. Every list element until the next '-' is interpreted as a method argument. configure/tt> is called before the constructor during initialization and recreation. In the following example, the variable set is called via configure before init: <@pre class='code'> Object o -set x 4 The method configure can be called with the dash-notation at arbitrary times: <@pre class='code'> o configure -set x 4 } return "number of the skipped first arguments" } @ Object instproc contains { "?-withnew?" "Option to overload new to create new objects within the specified object. Per default, this option is turned on." "?-object?" "object, in which the new objects should be created. The default is the object, for which contains>/tt> was called." "?-class?" "In combination with option -object: If the specified object does not exist, create it from the specified class. The default is ::xotcl::Object" cmd "Tcl command to create multiple objects" } { Description { This method can be used to create nested object structures with little syntactic overhead. The method changes the namespace to the specified object and creates objects there. Optionally, a different object scope can be specified and creating new objects in the specified scope can be turned off. The following command creates a three rectangles, containing some points. 
  Class Point -parameter {{x 100} {y 300}}
  Class Rectangle -parameter {color}

  Rectangle r0 -color pink -contains {
    Rectangle r1 -color red -contains {
      Point x1 -x 1 -y 2
      Point x2 -x 1 -y 2
    }
    Rectangle r2 -color green -contains {
      Point x1
      Point x2
    }
  }
The resulting object structure looks like in the folloing example (simplified). 
   ::r0
   ::r0::r1
   ::r0::r1::x1
   ::r0::r1::x2
   ::r0::r2
   ::r0::r2::x1
   ::r0::r2::x2
} return "number of the skipped first arguments" } @ Object instproc copy { newName "destination of copy operation" } { Description { Perform a deep copy of the object/class (with all information, like class, parameter, filter, ...) to "newName". } return "empty string" } @ Object instproc destroy { ?args? "Arbitrary arguments passed to the destructor" } { Description { Standard destructor. Can be overloaded for customized destruction process. Actual destruction is done by instdestroy. "destroy" in principal does: <@pre class='code'> Object instproc destroy args { [my info class] instdestroy [self] } } return "empty string" } @ Object instproc eval { args "cmds to eval" } { Description { Eval args in the scope of the object. That is local variables are directly accessible as Tcl vars. } return "result of cmds evaled" } @ Object instproc extractConfigureArg { al "Argument List Name" name "Name of the configure argument to be extracted (should start with '-')" ?cutTheArg? "if cutTheArg not 0, it cut from upvar argsList, default is 0" } { Description { Check an argument list separated with '-' args, as for instance configure arguments, and extract the argument's values. Optionally, cut the whole argument. } return "value list of the argument" } @ Object instproc exists { var "variable name" } { Description { Check for existence of the named instance variable on the object. } return "1 if variable exists, 0 if not" } @ Object instproc filter { ?args? "filter specification" } { Description { If <@tt>$args is one argument, it specifies a list of filters to be set. Every filter must be an XOTcl proc/instproc within the object scope. If <@tt>$args it has more argument, the first one specifies the action. Possible values are <@tt>assign, <@tt>get, <@tt>add or <@tt>delete, it modifies the current settings as indicated. For more details, check the tutorial. } return "if <@tt>$args return empty current filters, otherwise empty" } @ Object instproc filterguard { filterName "filter name of a registered filter" guard "set of conditions to execute the filter" } { description { Add conditions to guard a filter registration point. The filter is only executed, if the guards are true. Otherwise we ignore the filter. If no guards are given, we always execute the filter. } return "an empty string" } @ Object instproc filtersearch { methodName "filter method name" } { description { Search a full qualified method name that is currently registered as a filter. Return a list of the proc qualifier format: 'objName|className proc|instproc methodName'. } return "full qualified name, if filter is found, otherwise an empty string" } @ Object instproc forward { methodName "name of forwarder method" ?options? "-objscope, -methodprefix string, -default names, -earlybinding, -verbose" ?callee? "named of the called command or object" ?args? "arguments" } { Description { Register an object specific method (similar to a proc) for forwarding calls to a callee (target Tcl command, other object). When the forwarder method is called, the actual arguments of the invocation are appended to the specified arguments. In callee an arguments certain substitutions can take place: Additionally each argument can be prefixed by the positional prefix %@POS (note the delimiting space at the end) that can be used to specify an explicit position. POS can be a positive or negative integer or the word end. The positional arguments are evaluated from left to right and should be used in ascending order. valid Options are: See tutorial for detailed examples. } return "empty" } @ Object instproc hasclass { ?className? "name of a class to be tested" } { Description { Test whether the argument is either a mixin or instmixin of the object or if it is on the class hierarchy of the object. This method combines the functionalities of istype and ismixin. } return "1 or 0" } @ Object instproc incr { varName "variable name" ?increment? "value to increment" } { Description { Increments the value stored in the variable whose name is varName. The new value is stored as a decimal string in variable varName and also returned as result. Wrapper to the same named Tcl command (see documentation of Tcl command with the same name for details). } return "new value of varName" } @ Object instproc info { args "info options" } { Description { Introspection of objects. The following options can be specified: <@l> <@li><@TT>objName info args method: Returns the arguments of the specified proc (object specific method). <@li><@TT>objName info body method: Returns the body of the specified proc (object specific method). <@li><@TT>objName info class ?classname?: Returns the name of the class of the current object, if className was not specified, otherwise it returns 1 if className matches the object's class and 0 if not. <@li><@TT>objName info children ?pattern?: Returns the list of aggregated objects with fully qualified names if <@TT>pattern was not specified, otherwise it returns all children where the object name matches the pattern. <@li><@TT>objName info commands ?pattern: Returns all commands defined for the object if <@TT>pattern was not specified, otherwise it returns all commands that match the pattern. <@li><@TT>objName info default method arg var: Returns 1 if the argument <@TT>arg of the proc (object specific method) <@TT>method has a default value, otherwise 0. If it exists the default value is stored in <@TT>var. <@li><@TT>objName info filter: Returns a list of filters. With -guard modifier all filterguards are integrated (<@TT> objName info filter -guards). With <@TT>-order modifier the order of filters (whole hierarchy) is printed. <@li><@TT>objName info filterguard name: Returns the guards for filter identified by name. <@li><@TT>objName info hasNamespace: From XOTcl version 0.9 on, namespaces of objects are allocated on demand. hasNamespace returns 1, if the object currently has a namespace, otherwise 0. The method <@TT>requireNamespace can be used to ensure that the object has a namespace. <@li><@TT>objName info info: Returns a list of all available info options on the object. <@li><@TT>objName info invar: Returns object invariants. <@li><@TT>objName info methods: Returns the list of all methods currently reachable for objName. Includes procs, instprocs, cmds, instcommands on object, class hierarchy and mixins. Modifier <@TT>-noprocs only returns instcommands, <@TT>-nocmds only returns procs. Modifier <@TT>-nomixins excludes search on mixins. <@li><@TT>objName info mixin: Returns the list of mixins of the object. With <@TT>-order modifier the order of mixins (whole hierarchy) is printed. <@li><@TT>objName info nonposargs methodName: Returns non-positional arg list of methodName <@li><@TT>objName info parent: Returns parent object name (or "::" for no parent), in fully qualified form. <@li><@TT>objName info post methodName: Returns post assertions of methodName. <@li><@TT>objName info pre methodName: Returns pre assertions of methodName. <@li><@TT>objName info procs ?pattern?: Returns all procs defined for the object if <@TT>pattern was not specified, otherwise it returns all procs that match the pattern. <@li><@TT>objName info precedence ?pattern?: Returns all classes in the precedence order from which the specified object inherits methods. The returned list of classes contains the mixin and instmixin classes as well as the classes of the superclass chain in linearized order (i.e., duplicate classes are removed). If the pattern is specified, only matching classes are returned. <@li><@TT>objName info vars ?pattern?: Returns all variables defined for the object if <@TT>pattern was not specified, otherwise it returns all variables that match the pattern. <@/ul> } return "Value of introspected option as a string." } @ Object instproc instvar { v1 "name of instance variable" "?v2...vn?" "optional other names for instance variables" } { Description { Binds an variable of the object to the current method's scope. Example: <@pre class='code'> kitchen proc enter {name} { my instvar persons set persons($name) [clock seconds] } Now persons can be accessed as a local variable of the method.<@br> A special syntax is: <@tt> {varName aliasName} . This gives the variable with the name <@TT>varName the alias <@TT>aliasName. This way the variables can be linked to the methods scope, even if a variable with that name already exists in the scope. } return "empty string" } @ Object instproc invar { invariantList "Body of invariants for the object" } { Description { Specify invariants for the objects. All assertions are a list of ordinary Tcl conditions. } return "empty string" } @ Object instproc isclass { ?className? "name of a class to be tested" } { Description { Test whether the argument (or the Object, if no argument is specified) is an existing class or not. } return "1 or 0" } @ Object instproc ismetaclass { ?metaClassName? "name of a metaclass to be tested" } { Description { Test whether the argument (or the Object, if no argument is specified) is an existing metaclass or not. } return "1 or 0" } @ Object instproc ismixin { ?className? "name of a class to be tested" } { Description { Test whether the argument is a mixin or instmixin of the object. } return "1 or 0" } @ Object instproc isobject { objName "string that should be tested, whether it is a name of an object or not" } { Description { Test whether the argument is an existing object or not. Every XOTcl object has the capability to check the object system. } return "1 or 0" } @ Object instproc istype { className "type name" } { Description { Test whether the argument is a type of the object. I.e., 1 is returned if className is either the class of the object or one of its superclasses. } return "1 or 0" } @ Object instproc lappend { varName "name of variable" args "elements to append" } { Description { Append all the specified arguments to the list specified by varName as separated elements (typically separated by blanks). If varName doesn't exist, it creates a list with the specified values (see documentation of Tcl command with the same name for details). } return "empty string" } @ Object instproc mixin { ?args? "mixin specification" } { Description { If <@tt>$args is one argument, it specifies a list of mixins to be set. Every mixin must be a defined class. If <@tt>$args has more argument, the first one specifies the action. Possible values are <@tt>assign, <@tt>get, <@tt>add or <@tt>delete, it modifies the current settings as indicated. For more details, check the tutorial. } return "if <@tt>$args empty return current mixins, otherwise empty" } @ Object instproc move { newName "destination of move operation" } { Description { Perform a deep move of the object/class (with all information, like class, parameter, filter, ...) to "newName". Note that move is currently implemented as a copy plus subsequent destroy operation. } return "empty string" } @ Object instproc parametercmd { name "variable to be provided with getter/setter method" } { description { Add a getter/setter for an instance variable with the specified name as a command for the obj. Example: <@pre class='code'> Object o o parametercmd x o x 100 puts [o x] } return "empty string" } @ Object instproc noinit { } { description { flag that constructor (method <@tt>init) should not be called. Example: <@pre class='code'> Class C C instproc init {} {puts hu} C c1 -noinit The object <@tt>c1 will be created without calling the constructor. This can be used to draw a snapshot of an existing object (using the serializer) and to recreate it in some other context in its last state. } return "empty string" } @ Object instproc proc { name "method name" ?non-pos-args? "optional non-positional arguments" args "method arguments" body "method body" "?preAssertion?" "optional assertions that must hold before the proc executes" "?postAssertion?" "optional assertions that must hold after the proc executes" } { Description { Specify a method in the same style as Tcl specifies procs. <@br> Optionally assertions may be specified by two additional arguments. Therefore, to specify only post-assertions an empty pre-assertion list must be given. All assertions are a list of ordinary Tcl conditions. <@br> When instproc is called with an empty argument list and an empty body, the specified instproc is deleted. } return "empty string" } @ Object instproc procsearch { procName "simple proc name" } { Description { Search which method should be invoked for an object and return the fully qualified name of the method as a list in proc qualifier format: 'objName|className proc|instproc|forward|instforward|parametercmd|instparametercmd|cmd|instcmd methodName'. The proc qualifier format reports the command used to create the method. The only exception is instcmd and cmd, which refer to commands implemented in C. E.g., <@pre class='code'> o procsearch set returns <@pre>::xotcl::Object instcmd set. } return "fully qualified name of the searched method or empty string if not found" } @ Object instproc requireNamespace { } { Description { The method <@TT>requireNamespace can be used to ensure that the object has a namespace. Namespaces are created automatically by XOTcl, when e.g. an object has child objects (aggregated objects) or procs. The namespace will be used to keep instance variables, procs and child objects. To check, whether an object currently has a namespace, <@TT>info hasNamespace can be used. Hint: In versions prior to XOTcl 0.9 all XOTcl objects had their own namespaces; it was made on demand to save memory when e.g. huge numbers of objects are created. <@TT>requireNamespace is often needed when e.g. using Tk widgets when variables are to be referenced via the namespace (with <@TT>... -variable [self]::varName ...). } return "empty string" } @ Object instproc set { varName "name of the instance variable" ?value? "optional new value" } { Description { Set an instance variable in the same style as Tcl sets a variable. With one argument, we retrieve the current value, with two arguments, we set the instance variable to the new value. } return "Value of the instance variable" } @ Object instproc subst { options "?-nobackslashes? ?-nocommands? ?-novariables?" string "string to be substituted" } { Description { Perform backslash, command, and variable substitutions in the scope of the given object (see documentation of Tcl command with the same name for details). } return "substituted string" } @ Object instproc trace { varName "name of variable" } { Description { Trace an object variable (see documentation of Tcl command with the same name for details). } return "empty string" } @ Object instproc unset { "?-nocomplain?" "possible error messages are suppressed" v1 "Variable to unset" "?v2...vn?" "Optional more vars to unset" } { Description { The unset operation deletes one or optionally a set of variables from an object. } return "empty string" } @ Object instproc uplevel { ?level? "Level" command ?args? "command and arguments to be called" } { Description { When this method is used without the optional level, it is a short form of the Tcl command <@pre class='code'> uplevel [self callinglevel] command ?args?<@/pre> When it is called with the level, it is compatible with the original Tcl command. } return "result of the command" } @ Object instproc upvar { ?level? "Level" otherVar localVar "referenced variable and variable in the local scope" ?otherVar localVar? "optional pairs of referenced and local variable names" } { Description { When this method is used without the optional level, it is a short form of the Tcl command <@pre class='code'> upvar [self callinglevel] otherVar localVar ?...?<@/pre>. When it is called with the level, it is compatible with the original Tcl command. } return "result of the command" } @ Object instproc vwait { varName "name of variable" } { Description { Enter event loop until the specified variable is set (see documentation of Tcl command with the same name for details). } return "empty string" } # procs of Object @ Object proc getExitHandler {} { Description "Retrieve the current exit handler procedure body as a string." return "exit handler proc body" } @ Object proc setExitHandler {body "procedure body"} { Description { Set body for the exit handler procedure. The exit handler is executed when XOTcl is existed or aborted. Can be used to call cleanups that are not associated with objects (otherwise use destructor). On exit the object destructors are called after the user-defined exit-handler. } return "exit handler proc body" } # class @ Class Class -superclass Object { description { This meta-class holds the pre-defined methods available for all XOTcl classes. } } @ Class instproc alloc { obj "new obj/class name" ?args? "arguments passed to the new class after creation" } { description { Allocate memory for a new XOTcl object or class. <@tt>create<@/tt> uses <@tt>alloc to allocate memory. But <@tt>create<@/tt> also calls init and evaluates '-' arguments as method calls. In seldom cases the programmer may want to suppress the <@tt>create<@/tt> mechanism and just allocate memory. Then <@tt>alloc can be used. } return "new class name" } @ Class instproc allinstances { } { description { Compute all immediate and indirect instances of a class } return "fully qualified list of instances" } @ Class instproc create { objName "name of a new class or object" ?args? "arguments passed to the constructor" } { description { Create user-defined classes or objects. If the class is a meta-class, a class is created, otherwise an object. Create firstly calls <@tt>alloc in order to allocate memory for the new object. Then default values for parameters are searched on superclasses (an set if found). Then <@tt>args is searched for args starting with '-' followed by an alpha character. These arguments are called as methods. '-' followed by a numerical is interpreted as a negative number (and not as a method). If a value of a method called this way starts with a "a", the call can be placed safely into a list (e.g. "Class c [-strangearg -a-] -simplearg 2"). Finally the constructor <@tt>init is called on the object with all arguments up to the first '-' arg.<@p> The <@tt>create method is called implicitly through the <@tt>unknown mechanism when a class (meta-class) is called with an unknown method. E.g. the following two commands are equivalent <@pre class='code'> Car herby -color red Car create herby -color red <@/pre> When a users may want to call the constructor <@tt>init before other '-' methods, one can specify '-init' explicitly in the left to right order of the '-' method. Init is called always only once. e.g.: <@pre class='code'> Class Car -init -superclass Vehicle <@/pre> } return "name of the created instance (result of alloc)" } @ Class instproc info { args "info options" } { Description { Introspection of classes. All options available for objects (see <@a href="#Object-info">info object) is also available for classes. The following options can be specified: <@ul> <@li><@TT>ClassName info classchildren ?pattern?: Returns the list of nested classes with fully qualified names if <@TT>pattern was not specified, otherwise it returns all class children where the class name matches the pattern. <@li><@TT>ClassName info classparent: Returns the class ClassName is nesting to. <@li><@TT>ClassName info heritage ?pattern?: Returns a list of all classes in the precedence order of the class hierarchy. If pattern is specified, only matching values are returned. <@li><@TT>ClassName info instances ?pattern?: Returns a list of the instances of the class. If pattern is specified, only matching values are returned. <@li><@TT>ClassName info instargs method: Returns the arguments of the specified instproc (instance method). <@li><@TT>ClassName info instbody method: Returns the body of the specified instproc (instance method). <@li><@TT>ClassName info instcommands ?pattern?: Returns all commands defined for the class. If pattern is specified it returns all commands that match the pattern. <@li><@TT>ClassName info instdefault method arg var: Returns 1 if the argument <@TT>arg of the instproc (instance method) <@TT>method has a default value, otherwise 0. If it exists the default value is stored in <@TT>var. <@li><@TT>ClassName info instfilter: Returns the list of registered filters. With -guard modifier all instfilterguards are integrated (<@TT> ClassName info instfilter -guards). <@li><@TT>objName info instfilterguard name: Returns the guards for instfilter identified by name. <@li><@TT>ClassName info instinvar: Returns class invariants. <@li><@TT>ClassName info instmixin: Returns the list of instmixins of this class. <@li><@TT>ClassName info instnonposargs methodName: returns list of non-positional args of methodName <@li><@TT>ClassName info instpost methodName: Returns post assertions of methodName. <@li><@TT>ClassName info instpre methodName: Returns pre assertions of methodName. <@li><@TT>ClassName info instprocs ?pattern?: Returns all instprocs defined for the class. If pattern is specified it returns all instprocs that match the pattern. <@li><@TT>ClassName info parameter: Returns parameter list. <@li><@TT>ClassName info subclass ?subclassname?: Returns a list of all subclasses of the class, if subclassname was not specified, otherwise it returns 1 if subclassname is a subclass and 0 if not. <@li><@TT> ClassName info superclass ?superclassname?: Returns a list of all super-classes of the class, if superclassname was not specified, otherwise it returns 1 if superclassname is a superclass and 0 if not. <@/ul> } return "Value of introspected option as a string." } @ Class instproc instdestroy { obj "obj/class name" ?args? "arguments passed to the destructor" } { Description { Standard destructor. Destroys XOTcl object physically from the memory. Can be overloaded for customized destruction process. <@p> In XOTcl objects are not directly destroyed, when a destroy is encountered in a method. Beforehand, the interpreter looks up whether the object is still referenced on the method callstack or not. If not, the object is directly destroyed. Otherwise every occurrence of the object on the callstack is marked as destroyed. During popping of the callstack, for each object marked as destroyed, the reference count is decremented by one. When no more references to the object are on the callstack the object is physically destroyed. This way we can assure that objects are not accessed with [self] in running methods after they are physically destroyed. } return "empty string" } @ Class instproc instfilter { ?args? "instfilter specification" } { Description { If <@tt>$args is one argument, it specifies a list of instfilters to be set. Every filter must be an XOTcl proc/instproc within the object scope. If <@tt>$args it has more argument, the first one specifies the action. Possible values are <@tt>assign, <@tt>get, <@tt>add or <@tt>delete, it modifies the current settings as indicated. For more details, check the tutorial. } return "if <@tt>$args return empty current instfilters, otherwise empty" } @ Class instproc instfilterguard { filterName "filter name of a registered filter" guard "set of conditions to execute the filter" } { description { Add conditions to guard a filter registration point. The filter is only executed, if the guards are true. Otherwise we ignore the filter. If no guards are given, we always execute the filter. } return "empty string" } @ Class instproc instforward { methodName "name of forwarder method" ?options? "-objscope, -methodprefix string, -default names, -earlybinding, -verbose" ?callee? "named of the called command or object" ?args? "arguments" } { Description { Register a method for the instances of a class (similar to an instproc) for forwarding calls to a callee (target Tcl command, other object). When the forwarder method is called, the actual arguments of the invocation are appended to the specified arguments. In callee an arguments certain substitutions can take place: Additionally each argument can be prefixed by the positional prefix %@POS (note the delimiting space at the end) that can be used to specify an explicit position. POS can be a positive or negative integer or the word end. The positional arguments are evaluated from left to right and should be used in ascending order. valid Options are: See tutorial for detailed examples. } return "empty" } @ Class instproc instinvar { invariantList "Body of invariants for the class" } { Description { Specify invariants for the class. These are inherited by sub-classes. The invariants must hold for all instances. All assertions are a list of ordinary Tcl conditions. } return "empty string" } @ Class instproc instmixin { ?args? "instmixin specification" } { Description { If <@tt>$args is one argument, it specifies a list of instmixins to be set. Every instmixin must be a defined class. If <@tt>$args has more argument, the first one specifies the action. Possible values are <@tt>assign, <@tt>get, <@tt>add or <@tt>delete, it modifies the current settings as indicated. For more details, check the tutorial. } return "if <@tt>$args empty return current instmixins, otherwise empty" } @ Class instproc instparametercmd { name "variable to be provided with getter/setter method" } { description { Add a getter/setter command for an instance variable with the specified name. This method is used for example by the <@A href="#Class-parameter">parameter method. Example: <@br> <@pre class='code'> Class C C instparametercmd x C c1 -x 100 puts [c1 x] } return "empty string" } @ Class instproc instproc { name "instance method name" ?non-pos-args?" "optional non-positional arguments" args "instance method arguments" body "instance method body" "?preAssertion?" "optional assertions that must hold before the proc executes" "?postAssertion?" "optional assertions that must hold after the proc executes" } { Description { Specify an instance method in the same style as Tcl specifies procs. <@br> Optionally assertions may be given by two additional arguments. Therefore, to specify only post-assertions an empty pre-assertion list must be given. All assertions are a list of ordinary Tcl conditions. <@br> When instproc is called with an empty argument list and an empty body, the specified instproc is deleted. } return "empty string" } @ Class instproc new { "?-childof obj? ?args?" "args passed to create" } { description { Convenience method to create an autonamed object. E.g.: <@pre class='code'> HTTP new creates ::xotcl::__#0, a subsequent call creates ::xotcl::__#1, ...<@br> If <@tt>-childof obj is specified, the new object is created as a child of the specified object. } return "new object name" } @ Class instproc parameter { parameterList "list of parameter definitions" } { description { Specify parameters automatically created for each instance. Parameters denote instance variables which are available on each class instance and that have a getter/setter method with their own name. Parameters are specified in a parameter list of the form {p1 p2 ... pn}. p1 ... pn may either be parameter names or definitions of the form {parameterName defaultValue}. If a default value is given, that parameter is created during creation process of the instance object, otherwise only the getter/setter method is created (and the parameter does not exist). The getter/setter method has the same name as the parameter. It gets and returns the parameter, if no argument is specified. With one argument, the parameter is set to the argument value. <@br> Example: <@pre class='code'> Class Car -parameter {{doors 4} color} Car herby -doors 2 -color green <@/pre> } return "empty string" } @ Class instproc parameterclass { class "parameter class name" } { description { Set the parameter class. The parameter class specifies how parameters are stored and maintained internally. Per default, a method "default" is called, to set the parameter with a default value. I.e., <@pre class='code'> Class Car -parameter { {doors 4} }<@/pre> is a short form for <@pre class='code'> Class Car -parameter { {doors -default 4} }<@/pre> For specialized parameter classes other methods can be called, e.g.<@br> <@pre class='code'> {doors -default 3 -updateWidget car}<@/pre> } return "empty string" } @ Class instproc recreate { obj "obj to be recreated" ?args? "arbitrary arguments" } { description { Hook called upon recreation of an object. Performs standard object initialization, per default. May be overloaded/-written. It calls another method cleanup which handles actual cleanup of the object during next. That means, if you overload recreate, in the pre-part the object still contains its old state, after next it is cleaned up. } return "obj name" } @ Class instproc superclass { classList "?list of classes?" } { description { Specify super-classes for a class. "superclass" changes the list of superclasses dynamically to <@tt>classList. The method returns the current value of superclass, when it is called without arguments. } return "if <@tt>classList is not specified return superclass(es), otherwise empty" } @ Class instproc unknown { ?args? "arbitrary arguments" } { description { Standard unknown mechanism. This mechanism is always triggered when XOTcl does not know a method called on an object. Supposed that there is no method with the called name, XOTcl looks up the method "unknown" (which is found on the Class Object) and executes it. The standard unknown-mechanism of XOTcl calls create with all arguments stepping one step to the right; in the general case: <@pre class='code'> ClassName create ClassName ?args?<@/pre> Unknown can be overloaded in user-defined subclasses of class. } return "Standard unknown mechanism returns result of create" } @ Object instproc volatile { "" "" } { description { This method is used to specify that the object should be deleted automatically, when the current Tcl-proc/object-proc/instproc is left. Example: <@pre class='code'> set x [Object new -volatile] } return "empty string" } @ Class proc __unknown { "name" "name of class to be created" } { description { This method is called, whenever XOTcl references a class, which is not defined yet. In the following example: <@tt>Class C -superclass D D is not defined. Therefore <@tt>Class __unknown D is called. This callback can be used to perform auto-loading of classes. After this call, XOTcl tries again to resolve D. If it succeeds, XOTcl will continue; otherwise, an error is generated. <@p> This method is called on mixin/instmixin definition calls, istype, ismixin, class, superclass and parameterclass } return "empty string" } @ Class ::xotcl::Slot -superclass Object { description { A slot is a meta-object that manages property-changes of objects. A property is either an attribute or a role of an relation (e.g. in system slots). The predefined system slots are class, superclass, mixin, instmixin, filter, instfilter. These slots appear as methods of Object or Class.

The slots provide a common query and setting interface. Every multivalued slot provides e.g. a method add to add a value to the list of values, and a method delete which removes it. See for example the documentation of the slot mixin.

Parameters:

-name Name of the slot to access from an object the slot
-domain domain (object or class) of a slot on which it can be used
-multivalued boolean value for specifying single or multiple values (lists)
-defaultmethods list of two elements for specifying which methods are called per default, when no slot method is explicitly specified
-manager the manager object of the slot (per default [self])
-per-object specify whether a slot should be used per class or per object; note that there is a restricted usage if applied per class, since defaults etc, work per initialization

For more details, consult the tutorial.

} } @ Class Attribute -superclass ::xotcl::Slot { description { Attribute slots are used to manage the setting and querying of instance variables. Parameters:

-default specify a default value
-type specify the type of a slot
-initcmd specify a Tcl command to be executed when the value of the associated variable is read the first time; allows lazy initialization
-valuecmd specify a Tcl command to be executed whenever the variable is read
-valuechangedcmd specify a Tcl command to be executed whenever the variable is changed

Example of a class definition with three attribute slots:

  <@tt>Class Person -slots {
    Attribute name
    Attribute salary -default 0
    Attribute projects -default {} -multivalued true
  }
  Person p1 -name "John Doe"


   
 The slot parameters default, initcmd and
   valuecmd have to be used mutually exclusively. 
    For more details, consult the       
    tutorial.
    

  }
}




#Class::Parameter instproc values {param args}

#proc xotcl_mkindex
#proc xotcl_load