aliasobj ?public | private | protected? objectalias ?-debug? ?-deprecated? methodName ?-returnsvalueChecker? ?-frameobject | method? cmdName
Define an alias method for the given object. The resulting method registers a pre-existing
Tcl command cmdName under the (alias) name methodName with the object. If cmdName refers to
another method, the corresponding argument should be a valid method handle. If a Tcl
command (e.g., a proc), the argument should be a fully qualified Tcl command name. If
aliasing a subcommand (e.g., arrayexists) of a Tcl namespace ensemble (e.g., array),
cmdName must hold the fully qualified subcommand name (and not the ensemble name of the
subcommand).
As for a regular objectmethod, -returns allows for setting a value checker on the values
returned by the aliased command cmdName.
When creating an alias method for a C-implemented Tcl command (i.e., command defined using
the Tcl/NX C-API), -frame sets the scope for variable references used in the aliased
command. If the provided value is object, then variable references will be resolved in the
context of the called object, i.e., the object upon which the alias method is invoked, as
if they were object variables. There is no need for using the colon-prefix notation for
identifying object variables. If the value is method, then the aliased command will be
executed as a regular method call. The command is aware of its called-object context; i.e.,
it can resolve ::nx::self. In addition, the alias method has access to the method-call
context (e.g., nx::next). If -frame is omitted, and by default, the variable references
will resolve in the context of the caller of the alias method.
To express deprecation of the alias method methodName, set the -deprecated flag. Deprecated
methods remain usable from client code, but their usage will be signaled to the developer
and/or can be tracked using ::nsf::deprecated. To register methodName with the debugger,
set the -debug flag. Entering and exiting a method, which was flagged for debugging, is
recorded by calling the redefinable callback procs ::nsf::debug::call and
::nsf::debug::exit, respectively. By default, these callbacks forward to ::nsf::log, which
can also be customized at the script level.
cgetobjcgetconfigurationOption
The method is used to obtain the current value of configurationOption for obj. The
configuration options available for querying through cget are determined by the
configurable properties defined by the class hierarchy of obj. The queryable configuration
options for obj can be obtained by calling infolookupsyntaxconfigure. The
configurationOption can be set and modified using configure.
% nx::Object create obj
::obj
% ::obj info lookup syntax configure
?-object-mixins /mixinreg .../? ?-class /class/? ?-object-filters /filterreg .../? ?/__initblock/?
% ::obj cget -class
::nx::Object
configureobjconfigure ?configurationOptionvalue ...?
This method sets configuration options on an object. The configuration options available
for setting on obj are determined by the configurable properties defined by the class
hierarchy of obj. The settable configuration options for obj can be obtained by calling
infolookupsyntaxconfigure. Furthermore, configure is also called during object
construction. Under object construction, it receives the arguments passed into calls of
create and new. Options set using configure can be retrieved using cget.
% nx::Class create Foo {:property x}
::Foo
% Foo create f1 -x 101
::f1
% f1 cget -x
101
% f1 configure -x 200
% f1 cget -x
200
containsobjcontains ?-withnew trueFalse? ?-object objectName? ?-class className? cmds
This method acts as a builder for nested object structures. Object and class construction
statements passed to this method as its last argument cmds are evaluated in a way so that
the receiver object obj becomes the parent of the newly constructed objects and classes.
This is realized by setting explicitly the namespace for constructing relatively named
objects. Fully qualified object names in cmds evade the nesting.
-withnew requests the automatic rescoping of objects created using new so that they become
nested into the receiver object obj, rather than being created in the default namespace for
autonamed objects (i.e., ::nsf). If turned off, autonamed objects do not become children of
obj.
The parent object objectName to be used instead of obj can be specified using -object. If
this explicitly set parent object does not exist prior to calling contains, it will be
created on the fly as a direct instance of nx::Object. Alternatively, using -class, a class
className other than nx::Object for the on-the-fly creation of objectName can be provided.
% nx::Class create Window {
:contains {
#
# Become children of Window, implicitly
#
nx::Class create Header; # Window::Header
nx::Object create Panel; # Window::Panel
}
#
# Explicitly declared a child of Window using [self]
#
nx::Class create [self]::Slider; # Window::Slider
#
# Fully-qualified objects do not become nested
#
nx::Class create ::Door; # ::Door
}
::Window
% ::Window info children
::Window::Panel ::Window::Header ::Window::Slider
copyobjcopy ?newObjectName?
Creates a full and deep copy of a source object obj. The object's copy features all
structural and behavioral properties of the source object, including object variables, per-
object methods, nested objects, slot objects, namespaces, filters, mixins, and traces. The
copy can be named explicitly, if newObjectName is provided, or it is named automatically
(in the spirit of new of nx::Class).
deleteobjdeleteobjectfeaturearg
This method serves as the equivalent to Tcl's rename for removing structural (properties,
variables) and behavioral features (methods) of the object:
objdeleteobjectpropertypropertyNameobjdeleteobjectvariablevariableNameobjdeleteobjectmethodmethodName
Removes a property propertyName, variable variableName, and method methodName,
respectively, previously defined for the scope of the object.
deleteobjectmethod can be equally used for removing regular methods (see objectmethod),
an alias method (see objectalias), and a forwarder method (see objectforward).
destroyobjdestroy
This method allows for explicitly destructing an object obj, potentially prior to obj being
destroyed by the object system (e.g. during the shutdown of the object system upon calling
exit):
[nx::Object new] destroy
By providing a custom implementation of destroy, the destruction procedure of obj can be
customized. Typically, once the application-specific destruction logic has completed, a
custom destroy will trigger the actual, physical object destruction via next.
% [nx::Object create obj {
:public method destroy {} {
puts "destroying [self]"
next; # physical destruction
}
}] destroy
destroying ::obj
A customized object-destruction scheme can be made shared between the instances of a class,
by defining the custom destroy for an application class:
% nx::Class create Foo {
:method destroy {} {
puts "destroying [self]"
next; # physical destruction
}
}
::Foo
% Foo create f1
::f1
% f1 destroy
destroying ::f1
Physical destruction is performed by clearing the in-memory object storage of obj. This is
achieved by passing obj into a call to dealloc provided by nx::Class. A near, scripted
equivalent to the C-implemented destroy provided by nx::Object would look as follows:
% Object method destroy {} {
[:info class] dealloc [self]
}
Note, however, that destroy is protected against application-level redefinition. Trying to
evaluate the above script snippet yields:
refuse to overwrite protected method 'destroy'; derive e.g. a subclass!
A custom destroy must be provided as a refinement in a subclass of nx::Object or in a mixin
class.
evalobjevalarg ?arg ...?
Evaluates a special Tcl script for the scope of obj in the style of Tcl's eval. There are,
however, notable differences to the standard eval: In this script, the colon-prefix
notation is available to dispatch to methods and to access variables of obj. Script-local
variables, which are thrown away once the evaluation of the script has completed, can be
defined to store intermediate results.
% nx::Object create obj {
:object property {bar 1}
:public object method foo {x} { return $x }
}
::obj
% ::obj eval {
set y [:foo ${:bar}]
}
1
filtersobjobjectfilterssubmethod ?arg ...?
Accesses and modifies the list of methods which are registered as filters with obj using a
specific setter or getter submethod:
objobjectfiltersaddspec ?index?
Inserts a single filter into the current list of filters of obj. Using index, a
position in the existing list of filters for inserting the new filter can be set. If
omitted, index defaults to the list head (0).
objobjectfiltersclear
Removes all filters from obj and returns the list of removed filters. Clearing is
equivalent to passing an empty list for filterSpecList to objectfilterset.
objobjectfiltersdelete ?-nocomplain? specPattern
Removes a single filter from the current list of filters of obj whose spec matches
specPattern. specPattern can contain special matching chars (see stringmatch).
objectfiltersdelete will throw an error if there is no matching filter, unless
-nocomplain is set.
objobjectfiltersget
Returns the list of current filter specifications registered for obj.
objobjectfiltersguardmethodName ?expr?
If expr is specified, registers a guard expression expr with a filter methodName.
This requires that the filter methodName has been previously set using objectfiltersset or added using objectfiltersadd. expr must be a valid Tcl expression
(see expr). An empty string for expr will clear the currently registered guard
expression for filter methodName.
If expr is omitted, returns the guard expression set on the filter methodName
defined for obj. If none is available, an empty string will be returned.
objobjectfiltersmethods ?pattern?
If pattern is omitted, returns all filter names which are defined by obj. By
specifying pattern, the returned filters can be limited to those whose names match
patterns (see stringmatch).
objobjectfilterssetfilterSpecListfilterSpecList takes a list of filter specs, with each spec being itself either a
one-element or a two-element list: methodName ?-guard guardExpr?. methodName
identifies an existing method of obj which becomes registered as a filter. If having
three elements, the third element guardExpr will be stored as a guard expression of
the filter. This guard expression must be a valid Tcl expression (see expr). expr is
evaluated when obj receives a message to determine whether the filter should
intercept the message. Guard expressions allow for realizing context-dependent or
conditional filter composition.
Every methodName in a spec must resolve to an existing method in the scope of the object.
To access and to manipulate the list of filters of obj, cget|configure-object-filters can
also be used.
forwardobj ?public | protected | private? objectforward ?-debug? ?-deprecated? methodName ?-prefixprefixName? ?-frameobject? ?-returnsvalueChecker? ?-verbose? ?target? ?arg ...?
Define a forward method for the given object. The definition of a forward method registers
a predefined, but changeable list of forwarder arguments under the (forwarder) name
methodName. Upon calling the forward method, the forwarder arguments are evaluated as a Tcl
command call. That is, if present, target is interpreted as a Tcl command (e.g., a Tcl proc
or an object) and the remainder of the forwarder arguments arg as arguments passed into
this command. The actual method arguments to the invocation of the forward method itself
are appended to the list of forwarder arguments. If target is omitted, the value of
methodName is implicitly set and used as target. This way, when providing a fully-qualified
Tcl command name as methodName without target, the unqualified methodName (namespacetail)
is used as the forwarder name; while the fully-qualified one serves as the target.
As for a regular objectmethod, -returns allows for setting a value checker on the values
returned by the resulting Tcl command call. When passing object to -frame, the resulting
Tcl command is evaluated in the context of the object receiving the forward method call.
This way, variable names used in the resulting execution of a command become resolved as
object variables.
To express deprecation of the forward method methodName, set the -deprecated flag.
Deprecated methods remain usable from client code, but their usage will be signaled to the
developer and/or can be tracked using ::nsf::deprecated. To register methodName with the
debugger, set the -debug flag. Entering and exiting a method, which was flagged for
debugging, is recorded by calling the redefinable callback procs ::nsf::debug::call and
::nsf::debug::exit, respectively. By default, these callbacks forward to ::nsf::log, which
can also be customized at the script level.
The list of forwarder arguments arg can contain as its elements a mix of literal values and
placeholders. Placeholders are prefixed with a percent symbol (%) and substituted for
concrete values upon calling the forward method. These placeholders allow for constructing
and for manipulating the arguments to be passed into the resulting command call on the fly:
• %method becomes substituted for the name of the forward method, i.e. methodName.
• %self becomes substituted for the name of the object receiving the call of the
forward method.
• %1 becomes substituted for the first method argument passed to the call of forward
method. This requires, in turn, that atleast one argument is passed along with the
method call.
Alternatively, %1 accepts an optional argument defaults: {%1defaults}. defaults
must be a valid Tcl list of two elements. For the first element, %1 is substituted
when there is no first method argument which can be consumed by %1. The second
element is inserted upon availability of a first method argument with the consumed
argument being appended right after the second list element. This placeholder is
typically used to define a pair of getter/setter methods.
• {%@indexvalue} becomes substituted for the specified value at position index in the
forwarder-arguments list, with index being either a positive integer, a negative
integer, or the literal value end (such as in Tcl's lindex). Positive integers
specify a list position relative to the list head, negative integers give a position
relative to the list tail. Indexes for positioning placeholders in the definition of
a forward method are evaluated from left to right and should be used in ascending
order.
Note that value can be a literal or any of the placeholders (e.g., %method, %self).
Position prefixes are exempted, they are evaluated as %cmdName-placeholders in this
context.
• {%argclindexlist} becomes substituted for the nth element of the provided list ,
with n corresponding to the number of method arguments passed to the forward method
call.
• %% is substituted for a single, literal percent symbol (%).
• %cmdName is substituted for the value returned from executing the Tcl command
cmdName. To pass arguments to cmdName, the placeholder should be wrapped into a Tcl
list: {%cmdName ?arg ...?}.
Consider using fully-qualified Tcl command names for cmdName to avoid possible name
conflicts with the predefined placeholders, e.g., %self vs. %::nx::self.
To disambiguate the names of subcommands or methods, which potentially become called by a forward
method, a prefix prefixName can be set using -prefix. This prefix is prepended automatically to
the argument following target (i.e., a second argument), if present. If missing, -prefix has no
effect on the forward method call.
To inspect and to debug the conversions performed by the above placeholders, setting the switch
-verbose will have the command list to be executed (i.e., after substitution) printed using
::nsf::log (debugging level: notice) upon calling the forward method.
infoobjinfobaseclass
Returns the base class of obj. The base class is the class from which all NX objects are
instantiated directly or indirectly (typically nx::Object).
objinfochildren ?-typeclassName? ?pattern?
Retrieves the list of nested (or aggregated) objects of obj. The resulting list contains
the fully qualified names of the nested objects. If -type is set, only nested objects which
are direct or indirect instances of class className are returned. Using pattern, only
nested objects whose names match pattern are returned. The pattern string can contain
special matching characters (see stringmatch). This method allows for introspecting on
contains.
objinfoclass
Returns the fully qualified name of the current nx::Class of obj. In case of re-
classification (see configure), the returned class will be different from the nx::Class
from which obj was originally instantiated using create or new.
objinfohas ?mixin | namespace | type? ?arg ...?
objinfohasmixinclassName
Verifies whether obj has a given nx::ClassclassName registered as a mixin class
(returns: true) or not (returns: false).
objinfohasnamespace
Checks whether the object has a companion Tcl namespace (returns: true) or not
(returns: false). The namespace could have been created using, for example, objectrequirenamespace.
objinfohastypeclassName
Tests whether the nx::ClassclassName is a type of the object (returns: true) or not
(returns: false). That is, the method checks whether the object is a direct instance
of className or an indirect instance of one of the superclasses of className.
objinfolookupsubmethod ?arg ...?
A collection of submethods to retrieve structural features (e.g. configuration options,
slot objects) and behavioral features (e.g. methods, filters) available for obj from the
perspective of a client to obj. Features provided by obj itself and by the classes in its
current linearization list are considered.
objinfolookupfiltername
Returns the method handle for the filter method name, if currently registered. If
there is no filter name registered, an empty string is returned.
objinfolookupfilters ?-guards? ?namePattern?
Returns the method handles of all filters which are active on obj. By turning on the
switch -guards, the corresponding guard expressions, if any, are also reported for
each filter as a three-element list: methodHandle -guard guardExpr. The returned
filters can be limited to those whose names match namePattern (see stringmatch).
objinfolookupmethodname
Returns the method handle for a method name if a so-named method can be invoked on
obj. If there is no method name, an empty string is returned.
objinfolookupmethods ?namePattern?
Returns the names of all methods (including aliases and forwarders) which can be
invoked on obj. The returned methods can be limited to those whose names match
namePattern (see stringmatch).
objinfolookupmixins ?-guards? ?namePattern?
Returns the object names of all mixin classes which are currently active on obj. By
turning on the switch -guards, the corresponding guard expressions, if any, are also
reported as a three-element list for each mixin class: className -guard guardExpr.
The returned mixin classes can be limited to those whose names match namePattern
(see stringmatch).
objinfolookupparametersmethodName ?namePattern?
Returns the parameter specification of the method methodName callable on obj as a
list of parameter names and type specifications. The resulting parameter
specification can be limited to those parameters whose names match namePattern (see
stringmatch).
objinfolookupslots ?-typeclassName? ?-source all | application | system? ?namePattern?
Returns the command names of all slot objects responsible for managing properties,
variables, and relations of obj. The returned slot objects can be limited according
to any or a combination of the following criteria: First, slot objects can be
filtered based on their command names matching namePattern (see stringmatch).
Second, -type allows one to select slot objects which are instantiated from a
subclass className of nx::Slot (default: nx::Slot) . Third, -source restricts slot
objects returned according to their provenance in either the NX system classes or
the application classes present in the linearization list of obj (default: all).
To extract details of each slot object, use the info submethods available for each
slot object.
objinfolookupsyntaxmethodName ?namePattern?
Returns the method parameters of the method methodName callable on obj as a
concrete-syntax description to be used in human-understandable messages (e.g.,
errors or warnings, documentation strings). The result can be limited to those
parameters matching the namePattern (see stringmatch).
objinfolookupvariables
Returns the command names of all slot objects responsible for managing properties
and variables of obj, if provided by obj or the classes in the linearization list of
obj.
This is equivalent to calling: objinfolookupslots -type ::nx::VariableSlot
-source all ?namePattern?.
To extract details of each slot object, use the info submethods available for each
slot object.
objinfoname
Returns the unqualified name of an object, i.e., the object name without any namespace
qualifiers.
objinfoinfo ?-asList?
Returns the available submethods of the info method ensemble for obj, either as a pretty-
printed string or as a Tcl list (if the switch -asList is set) for further processing.
objinfoobjectfilters ?-guards? ?pattern?
If pattern is omitted, returns all filter names which are defined by obj. By turning on the
switch -guards, the corresponding guard expressions, if any, are also reported along with
each filter as a three-element list: filterName -guard guardExpr. By specifying pattern,
the returned filters can be limited to those whose names match patterns (see stringmatch).
objinfoobjectmethodoptionmethodName
This introspection submethod provides access to the details of methodName provided by obj.
If methodName is not the name of an existing method, an empty string is returned. To
disambiguate between a non-existing method and an empty string as valid return value (e.g.,
for infoobjectmethodargs|parameters|args|...), use infoobjectmethodexists.
Permitted values for option are:
• args returns a list containing the parameter names of methodName, in order of the
method-parameter specification.
• body returns the body script of methodName.
• callprotection returns the call-protection level set for methodName; possible
values: public, protected, private.
• debug returns 1 if methodName is in debug mode, 0 otherwise.
• definition returns a canonical command list which allows for (re-)define methodName.
• definitionhandle returns the method handle for a submethod in a method ensemble from
the perspective of obj as method provider. methodName must contain a complete method
path.
• deprecated returns 1 if methodName is deprecated, 0 otherwise.
• exists returns 1 if there is a methodName provided by obj, returns 0 otherwise.
• handle returns the method handle for methodName.
• origin returns the aliased command if methodName is an alias method, or an empty
string otherwise.
• parameters returns the parameter specification of methodName as a list of parameter
names and type specifications.
• registrationhandle returns the method handle for a submethod in a method ensemble
from the perspective of the method caller. methodName must contain a complete method
path.
• returns gives the type specification defined for the return value of methodName.
• submethods returns the names of all submethods of methodName, if methodName is a
method ensemble. Otherwise, an empty string is returned.
• syntax returns the method parameters of methodName as a concrete-syntax description
to be used in human-understandable messages (e.g., errors or warnings, documentation
strings).
• type returns whether methodName is a scripted method, an alias method, a forwarder
method, or a setter method.
objinfoobjectmethods ?-callprotectionlevel? ?-typemethodType? ?-path? ?namePattern?
Returns the names of all methods defined by obj. Methods covered include those defined
using objectalias and objectforward. The returned methods can be limited to those whose
names match namePattern (see stringmatch).
By setting -callprotection, only methods of a certain call protection level (public,
protected, or private) will be returned. Methods of a specific type can be requested using
-type. The recognized values for methodType are:
• scripted denotes methods defined using objectmethod;
• alias denotes alias methods defined using objectalias;
• forwarder denotes forwarder methods defined using objectforward;
• setter denotes methods defined using ::nsf::setter;
• all returns methods of any type, without restrictions (also the default value);
objinfoobjectmixins ?-guards? ?pattern?
If pattern is omitted, returns the object names of the mixin classes which extend obj
directly. By turning on the switch -guards, the corresponding guard expressions, if any,
are also reported along with each mixin as a three-element list: className -guard
guardExpr. The returned mixin classes can be limited to those whose names match patterns
(see stringmatch).
objinfoobjectslots ?-typeclassName? ?pattern?
If pattern is not specified, returns the object names of all slot objects defined by obj.
The returned slot objects can be limited according to any or a combination of the following
criteria: First, slot objects can be filtered based on their command names matching pattern
(see stringmatch). Second, -type allows one to select slot objects which are instantiated
from a subclass className of nx::Slot (default: nx::Slot).
objinfoobjectvariables ?pattern?
If pattern is omitted, returns the object names of all slot objects provided by obj which
are responsible for managing properties and variables of obj. Otherwise, only slot objects
whose names match pattern are returned.
This is equivalent to calling: objinfoobjectslots-type::nx::VariableSlotpattern.
To extract details of each slot object, use the info submethods available for each slot
object.
objinfoparent
Returns the fully qualified name of the parent object of obj, if any. If there is no parent
object, the name of the Tcl namespace containing obj (e.g. "::") will be reported.
objinfoprecedence ?-intrinsic? ?pattern?
Lists the classes from which obj inherits structural (e.g. properties) and behavioral
features (e.g. methods) and methods, in order of the linearization scheme in NX. By setting
the switch -intrinsic, only classes which participate in superclass/subclass relationships
(i.e., intrinsic classes) are returned. If a pattern is provided only classes whose names
match pattern are returned. The pattern string can contain special matching characters (see
stringmatch).
objinfovariableoptionhandle
Retrieves selected details about a variable represented by the given handle. A handle can
be obtained by querying obj using infoobjectvariables and infolookupvariables. Valid
values for option are:
• name returns the variable name.
• parameter returns a canonical parameter specification eligible to (re-)define the
given variable (e.g. using objectvariable) in a new context.
• definition returns a canonical representation of the definition command used to
create the variable in its current configuration.
objinfovars ?pattern?
Yields a list of Tcl variable names created and defined for the scope of obj, i.e., object
variables. The list can be limited to object variables whose names match pattern. The
pattern string can contain special matching characters (see stringmatch).
methodobj ?public | protected | private? objectmethod ?-debug? ?-deprecated? nameparameters
?-checkalways? ?-returnsvalueChecker? body
Defines a scripted method methodName for the scope of the object. The method becomes part
of the object's signature interface. Besides a methodName, the method definition specifies
the method parameters and a method body.
parameters accepts a Tcl list containing an arbitrary number of non-positional and
positional parameter definitions. Each parameter definition comprises a parameter name, a
parameter-specific value checker, and parameter options.
The body contains the method implementation as a script block. In this body script, the
colon-prefix notation is available to denote an object variable and a self call. In
addition, the context of the object receiving the method call (i.e., the message) can be
accessed (e.g., using nx::self) and the call stack can be introspected (e.g., using
nx::current).
Optionally, -returns allows for setting a value checker on values returned by the method
implementation. By setting the switch -checkalways, value checking on arguments and return
value is guaranteed to be performed, even if value checking is temporarily disabled; see
nx::configure).
To express deprecation of the method name, set the -deprecated flag. Deprecated methods
remain usable from client code, but their usage will be signaled to the developer and/or
can be tracked using ::nsf::deprecated. To register name with the debugger, set the -debug
flag. Entering and exiting a method, which was flagged for debugging, is recorded by
calling the redefinable callback procs ::nsf::debug::call and ::nsf::debug::exit,
respectively. By default, these callbacks forward to ::nsf::log, which can also be
customized at the script level.
A method closely resembles a Tcl proc, but it differs in some important aspects: First, a
method can define non-positional parameters and value checkers on arguments. Second, the
script implementing the method body can contain object-specific notation and commands (see
above). Third, method calls cannot be intercepted using Tcl trace. Note that an existing
Tcl proc can be registered as an alias method with the object (see objectalias).
moveobjmovenewObjectName
Effectively renames an object. First, the source object obj is cloned into a target object
newObjectName using copy. Second, the source object obj is destroyed by invoking destroy.
move is also called internally when rename is performed for a Tcl command representing an
object.
mixinsobjobjectmixinssubmethod ?arg ...?
Accesses and modifies the list of mixin classes of obj using a specific setter or getter
submethod:
objobjectmixinsaddspec ?index?
Inserts a single mixin class into the current list of mixin classes of obj. Using
index, a position in the existing list of mixin classes for inserting the new mixin
class can be set. If omitted, index defaults to the list head (0).
objobjectmixinsclasses ?pattern?
If pattern is omitted, returns the object names of the mixin classes which extend
obj directly. By specifying pattern, the returned mixin classes can be limited to
those whose names match pattern (see stringmatch).
objobjectmixinsclear
Removes all mixin classes from obj and returns the list of removed mixin classes.
Clearing is equivalent to passing an empty list for mixinSpecList to objectmixinsset.
objobjectmixinsdelete ?-nocomplain? specPattern
Removes a mixin class from a current list of mixin classes of obj whose spec matches
specPattern. specPattern can contain special matching chars (see stringmatch).
objectmixinsdelete will throw an error if there is no matching mixin class, unless
-nocomplain is set.
objobjectmixinsget
Returns the list of current mixin specifications.
objobjectmixinsguardclassName ?expr?
If expr is specified, a guard expression expr is registered with the mixin class
className. This requires that the corresponding mixin class className has been
previously set using objectmixinsset or added using objectmixinsadd. expr must
be a valid Tcl expression (see expr). An empty string for expr will clear the
currently registered guard expression for the mixin class className.
If expr is not specified, returns the active guard expression. If none is available,
an empty string will be returned.
objobjectmixinssetmixinSpecListmixinSpecList represents a list of mixin class specs, with each spec being itself
either a one-element or a three-element list: className ?-guard guardExpr?. If
having one element, the element will be considered the className of the mixin class.
If having three elements, the third element guardExpr will be stored as a guard
expression of the mixin class. This guard expression will be evaluated using expr
when obj receives a message to determine if the mixin is to be considered during
method dispatch or not. Guard expressions allow for realizing context-dependent or
conditional mixin composition.
At the time of setting the mixin relation, that is, calling objectmixins, every className
as part of a spec must be an existing instance of nx::Class. To access and to manipulate
the list of mixin classes of obj, cget|configure-object-mixins can also be used.
__object_configureparameterobj__object_configureparameter
Computes and returns the configuration options available for obj, to be consumed as method-
parameter specification by configure.
propertyobjobjectproperty ?-accessorpublic | protected | private? ?-classclassName? ?-configurabletrueFalse? ?-incremental? ?-nocomplain? ?-traceset | get | default? spec ?initBlock?
Defines a property for the scope of the object. The spec provides the property
specification as a list holding at least one element or, maximum, two elements:
propertyName?:typeSpec? ?defaultValue?. The propertyName is also used as to form the names
of the getter/setter methods, if requested (see -accessor). It is, optionally, equipped
with a typeSpec following a colon delimiter which specifies a value checker for the values
which become assigned to the property. The second, optional element sets a defaultValue for
this property.
If -accessor is set, a property will provide for different getter and setter methods:
objpropertyNameexists
Returns 1 if the value store of propertyName (e.g., an object variable) exists and
has been given a value, returns 0 otherwise.
objpropertyNamesetvalue
Sets the property propertyName to value.
objpropertyNameget
Returns the current value of property propertyName.
objpropertyNameunset
Removes the value store of propertyName (e.g., an object variable), if existing.
The option value passed along -accessor sets the level of call protection for the generated
getter and setter methods: public, protected, or private. By default, no getter and setter
methods are created.
Turning on the switch -incremental provides a refined setter interface to the value managed
by the property. First, setting -incremental implies requesting -accessor (set to public by
default, if not specified explicitly). Second, the managed value will be considered a valid
Tcl list. A multiplicity of 1..* is set by default, if not specified explicitly as part of
spec. Third, to manage this list value element-wise (incrementally), two additional setter
methods become available:
objpropertyNameaddelement ?index?
Adding element to the managed list value, at the list position given by index (by
default: 0).
objpropertyNamedelete ?-nocomplain? elementPattern
Removing the first occurrence of an element from the managed list value which
matches elementPattern. elementPattern can contain matching characters (see stringmatch). An error will be thrown if there is no match, unless -nocomplain is set.
By setting -configurable to true (the default), the property can be accessed and modified through
cget and configure, respectively. If false, no configuration option will become available via cget
and configure.
If neither -accessor nor -configurable are requested, the value managed by the property will have
to be accessed and modified directly. If the property manages an object variable, its value will
be readable and writable using set and eval.
The -trace option causes certain slot methods to be executed whenever get, set, or default
operations are invoked on the property:
• set: slotvalue=setobjpropertyNamevalue
• get: slotvalue=getobjpropertyName
• default: slotvalue=defaultobjpropertyName
A property becomes implemented by a slot object under any of the following conditions:
• -configurable equals true (by default).
• -accessor is one of public, protected, or private.
• -incremental is turned on.
• initBlock is a non-empty string.
Assuming default settings, every property is realized by a slot object.
Provided a slot object managing the property is to be created, a custom class className
from which this slot object is to be instantiated can be set using -class. The default
value is ::nx::VariableSlot.
The last argument initBlock accepts an optional Tcl script which is passed into the
initialization procedure (see configure) of the property's slot object. See also initBlock
for create and new.
By default, the property will ascertain that no (potentially) pre-existing and equally
named object variable will be overwritten when defining the property. In case of a
conflict, an error exception is thrown:
% Object create obj { set :x 1 }
::obj
% ::obj object property {x 2}
object ::obj has already an instance variable named 'x'
If the switch -nocomplain is on, this check is omitted (continuing the above example):
% ::obj object property -nocomplain {x 2}
% ::obj eval {set :x}
2
requireobjrequirenamespace
Create a Tcl namespace named after the object obj. All object variables become available as
namespace variables.
objrequire ?public | protected | private? objectmethodmethodName
Attempts to register a method definition made available using ::nsf::method::provide under
the name methodName with obj . The registered method is subjected to default call
protection (protected), if not set explicitly.
unknownobjunknownunknownMethodName ?arg ...?
This method is called implicitly whenever an unknown method is invoked. unknownMethodName
indicates the unresolvable method name, followed by the remainder of the original argument
vector as a number of arg of the calling method invocation.
uplevelobjuplevel ?level? arg1 ?arg2 ...?
Evaluate a script or a command at a different stack-frame level. The command behaves in
essence like Tcl's uplevel, but can be used to achieve identical results when filters or
mixins are registered.
• If the level specifier is omitted, uplevel will skip any auxiliary frames added to
the stack by active filters and mixins. The resulting stack-frame level corresponds
to the callinglevel as indicated by nx::current. In this case method uplevel can be
used to evaluate the command in the next enclosing procedure call, i.e., a frame
corresponding to a proc, method, or apply call, while skipping frames of filters and
mixins.
• If the level specifier is provided (relative, or absolute), uplevel will execute the
command in the stack-frame level. In such cases, method uplevel behaves like Tcl's
uplevel command.
% nx::Object create ::obj
::obj
% ::obj public object method foo {varName} {
:uplevel set $varName 1; return
}
::obj::foo
% namespace eval ::ns1 {
::obj foo BAR
}
% namespace eval ::ns1 {
info exists BAR
}
1
Note, in the example above, uplevel is guaranteed to resolve to the calling context of foo (ns1)
despite mixins and filters being (potentially) registered on obj.
upvarobjupvar ?level? otherVar1localVar1 ?otherVar2localVar2 ...?
Links one or more local variables to variables defined in other scopes (namespaces,
objects, call frames). The command behaves in essence like Tcl's upvar, but can be used to
achieve identical results when filters or mixins are registered.
• If the level specifier is omitted, upvar will skip any auxiliary frames added to the
stack by active filters and mixins. The resulting stack-frame level corresponds to
the callinglevel as indicated by nx::current. Therefore, method upvar gives access
to the next enclosing procedure call, i.e., a frame corresponding to a proc, method,
or apply call, while skipping frames of filters and mixins.
• If the level specifier is provided (relative, or absolute), upvar will link into the
requested stack-frame level. In these cases, method upvar behaves like Tcl's upvar
command.
% nx::Object create ::obj
::obj
% ::obj public object method foo {varName} {
:upvar $varName x; set x 1; return
}
::obj::foo
% namespace eval ::ns1 {
::obj foo BAR
}
% namespace eval ::ns1 {
info exists BAR
}
1
Note, in the example above, upvar is guaranteed to resolve to the calling context of foo (ns1)
despite mixins and filters being (potentially) registered on obj.
variableobjobjectvariable ?-accessorpublic | protected | private? ?-incremental? ?-classclassName?
?-configurabletrueFalse? ?-initblockscript? ?-traceset | get | default? ?-nocomplain? spec
?defaultValue?
Defines a variable for the scope of the object. The spec provides the variable
specification: variableName?:typeSpec?. The variableName will be used to name the
underlying Tcl variable and the getter/setter methods, if requested (see -accessor). spec
is optionally equipped with a typeSpec following a colon delimiter which specifies a value
checker for the values managed by the variable. Optionally, a defaultValue can be defined.
If -accessor is set explicitly, a variable will provide for getter and setter methods:
objvariableNameexists
Returns 1 if the value store of variableName (e.g., an object variable) exists and
has been given a value, returns 0 otherwise.
objvariableNamesetvarValue
Sets variableName to varValue.
objvariableNameget
Returns the current value of variableName.
objvariableNameunset
Removes variableName, if existing, underlying the property.
The option value passed along -accessor sets the level of call protection for the getter
and setter methods: public, protected, or private. By default, no getter and setter methods
are created.
Turning on the switch -incremental provides a refined setter interface to the value managed
by the variable. First, setting -incremental implies requesting -accessor (public by
default, if not specified explicitly). Second, the managed value will be considered a valid
Tcl list. A multiplicity of 1..* is set by default, if not specified explicitly as part of
spec (see above). Third, to manage this list value element-wise (incrementally), two
additional setter operations become available:
objvariableNameaddelement ?index?
Adding element to the managed list value, at the list position given by index (by
default: 0).
objvariableNamedelete ?-nocomplain? elementPattern
Removing the first occurrence of an element from the managed list value which
matches elementPattern. elementPattern can contain matching characters (see stringmatch). An error will be thrown if there is no match, unless -nocomplain is set.
By setting -configurable to true, the variable can be accessed and modified via cget and
configure, respectively. If false (the default), the interface based on cget and configure will
not become available. In this case, and provided that -accessor is set, the variable can be
accessed and modified via the getter/setter methods. Alternatively, the underlying Tcl variable,
which is represented by the variable, can always be accessed and modified directly, e.g., using
eval. By default, -configurable is false.
The -trace option causes certain slot methods to be executed whenever get, set, or default
operations are invoked on the variable:
• set: slotvalue=setobjvariableNamevalue
• get: slotvalue=getobjvariableName
• default: slotvalue=defaultobjvariableName
A variable becomes implemented by a slot object under any of the following conditions:
• -configurable equals true.
• -accessor is one of public, protected, or private.
• -incremental is turned on.
• -initblock is a non-empty string.
Provided a slot object managing the variable is to be created, a custom class className
from which this slot object is to be instantiated can be set using -class. The default
value is ::nx::VariableSlot.
Using -initblock, an optional Tcl script can be defined which becomes passed into the
initialization procedure (see configure) of the variable's slot object. See also initBlock
for create and new.
By default, the variable will ascertain that a pre-existing and equally named object
variable will not be overwritten when defining the variable. In case of a conflict, an
error exception is thrown:
% Object create obj { set :x 1 }
::obj
% ::obj object variable x 2
object ::obj has already an instance variable named 'x'
If the switch -nocomplain is on, this check is omitted (continuing the above example):
% ::obj object variable -nocomplain x 2
% ::obj eval {set :x}
2
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