Introduction
... general text, maybe partly from slides/paper ....
Supporting XOTcl 1 in XOTcl 2
In general, the XOTcl 2 environment supports multiple object
systems concurrently. Effectively, every object system has different
base classes for creating both, objects and classes. Therefore, the
object systems can have different different interfaces and names of
builtin methods. Currently, XOTcl 2 supports primarily XOTcl 1 and
XOTcl 2 (XOTcl 1 provides about twice as many predefined builtin
methods).
The support for multiple object systems can be used to load XOTcl
1 and XOTcl 2 scripts into the same interpreter. This makes migration
from XOTcl 1 to XOTcl 2 easier. The XOTcl environment provides the
predefined command ::xotcl::use to make switching between these
objects systems convenient. The following example script shows a single
script defining classes of XOTcl 1 and 2:
package require XOTcl
namespace eval mypackage {
# Some definitions for XOTcl 1
::xotcl::use xotcl1
Class C1
C1 instproc foo {} {puts "hello world"}
# Some definitions for XOTcl 2
::xotcl::use xotcl2
Class create C2 {
.method foo {} {puts "hello world"}
}
}
"Switching" effectively means the load some libraries if needed
and to import either the XOTcl 1 or XOTcl 2 base classes as
Object
and Class
into the current namespace.
If the import is not wanted, just use package require
to
load the necessary pieces.
XOTcl 1 Idioms in XOTcl 2
Defining Objects and Classes
XOTcl 1 | XOTcl 2 |
Class ClassName |
Class create ClassName |
Object ObjectName |
Object create ObjectName |
::xotcl::Class ClassName |
::xotcl2::Class create ClassName |
::xotcl::Object ObjectName |
::xotcl2::Object create ObjectName |
Defining Methods
XOTcl 1 | XOTcl 2 |
Class C
C instproc foo args {...}
C proc bar args {...}
|
Class create C {
.method foo args {...}
.object method bar args {...}
}
Class create C
C method foo args {...}
C object method bar args {...}
|
Object o
o set x 1
o proc foo args {...}
|
Object create o {
set .x 1
.method foo args {...}
}
Object create o
o eval {set .x 1}
# ::xotcl::setinstvar o x 1
o method foo args {...}
|
Resolvers
XOTcl 2 defines Tcl resolvers for method and variable names to refer
to object specific behavior. Withing method bodies these resolver
treat names staring with a dot "." specially. If one wants to refer to
a name starting with a "." (e.g. the name of a Tcl function starts
with a dot), the dot has to be duplicated, or one has to use the
usual namespace prefix "::" to refer to a namespaced entity. Note that
the XOTcl 2 resolver is used in the XOTcl 1 environment as well.
Invoking Methods
XOTcl 1 | XOTcl 2 |
Class C
C instproc foo args {...}
C instproc bar args {
my foo 1 2 3 ;# invoke own method
o baz ;# invoke others method
}
Object o
o proc baz {} {...}
|
Class create C {
.method foo args {...}
.method bar args {
.foo 1 2 3 ;# invoke own method
o baz ;# invoke others method
}
}
Object create o {
.method baz {} {...}
}
|
Accessing Instance Variables from Method Bodies
XOTcl 1 | XOTcl 2 |
Class C
C instproc foo args {
# method scoped variable a
set a 1
# instance variable b
my instvar b
set b 2
# global variable/namespaced variable c
set ::c 3
}
|
Class create C {
.method foo args {...}
# method scoped variable a
set a 1
# instance variable b
set .b 2
# global variable/namespaced variable c
set ::c 3
}
}
|
my set varname value |
set .varname value |
set newVar [my set otherVar] |
set newVar [set .otherVar]
set newVar ${.otherVar}
|
my instvar newVar
set newVar value
|
set .newVar value |
my exists varname |
info .varname |
Accessing Instance Variables of other Objects
XOTcl 1 | XOTcl 2 |
obj set varname value |
obj eval [list set .varname value] |
set newVar [obj set otherVar] |
set newVar [obj eval {set .otherVar}]
|
obj instvar newVar
set newVar value
|
::xotcl::importvar obj newVar
set newVar value |
obj exists varname |
obj eval {info exists .varname} |
Object Parameters
Method Parameters
Introspection
List methods defined by objects
XOTcl 1 | XOTcl 2 |
obj info commands ?pattern? |
obj info methods ?pattern? |
obj info parametercmd ?pattern? |
obj info methods -methodtype setter ?pattern? |
obj info procs ?pattern? |
obj info methods -methodtype scripted ?pattern? |
n.a. |
obj info methods -methodtype alias ?pattern? |
n.a. |
obj info methods -methodtype forwarder ?pattern? |
n.a. |
obj info methods -methodtype object ?pattern? |
n.a. |
obj info methods -callprotection public|protected ... |
List methods defined by classes
cls info instcommands ?pattern? |
cls info methods ?pattern? |
cls info instparametercmd ?pattern? |
cls info methods -methodtype setter ?pattern? |
cls info instprocs ?pattern? |
cls info methods -methodtype scripted ?pattern? |
n.a. |
cls info methods -methodtype alias ?pattern? |
n.a. |
cls info methods -methodtype forwarder ?pattern? |
n.a. |
cls info methods -methodtype object ?pattern? |
n.a. |
cls info methods -callprotection public|protected ... |
List class object specific methods
cls info commands ?pattern? |
cls object info methods ?pattern? |
cls info parametercmd ?pattern? |
cls object info methods -methodtype setter ?pattern? |
cls info procs ?pattern? |
cls object info methods -methodtype scripted ?pattern? |
n.a. |
cls object info methods -methodtype alias ?pattern? |
n.a. |
cls object info methods -methodtype forwarder ?pattern? |
n.a. |
cls object info methods -methodtype object ?pattern? |
n.a. |
cls object info methods -callprotection public|protected ... |
List callable methods
XOTcl 1 | XOTcl 2 |
obj info methods ?pattern? |
obj info callable ?pattern? |
n.a. |
# list only application specific methods
obj info callable -application |
List object/class where some method is defined
XOTcl 1 | XOTcl 2 |
obj procsearch methodName |
obj info callable -which methodName |
List definition of scripted methods defined by classes
XOTcl 1 | XOTcl 2 |
cls info instbody methodName |
cls info method body methodName |
cls info instargs methodName |
cls info method args methodName |
cls info instnonposargs methodName |
cls info method parameter methodName |
cls info instdefault methodName |
cls info method parameter methodName |
cls info instpre methodName |
cls info method precondition methodName |
cls info instpost methodName |
cls info method postcondition methodName |
n.a. |
cls info method definition methodName |
List definition of scripted object specific methods
XOTcl 1 | XOTcl 2 |
obj info body methodName |
obj info method body methodName |
obj info args methodName |
obj info method args methodName |
obj info nonposargs methodName |
obj info method parameter methodName |
obj info default methodName |
obj info method parameter methodName |
obj info pre methodName |
obj info method precondition methodName |
obj info post methodName |
obj info method postcondition methodName |
n.a. |
obj info method definition methodName |
For definition of class object specific methods, use modifier
object
as shown in examples above.
List filter or mixins
XOTcl 1 | XOTcl 2 |
obj info filter ?-order? ?-guards? ?pattern? |
obj info filter ?-order? ?-guards? ?pattern? |
cls info filter ?-order? ?-guards? ?pattern? |
cls object info filter ?-order? ?-guards? ?pattern? |
cls info instfilter ?-order? ?-guards? ?pattern? |
cls info filter ?-order? ?-guards? ?pattern? |
obj info mixin ?-order? ?-guards? ?pattern? |
obj info mixin ?-order? ?-guards? ?pattern? |
cls info mixin ?-order? ?-guards? ?pattern? |
cls object info mixin ?-order? ?-guards? ?pattern? |
cls info instmixin ?-order? ?-guards? ?pattern? |
cls info mixin ?-order? ?-guards? ?pattern? |
List definition of methods defined by aliases, setters or forwarders
XOTcl 1 | XOTcl 2 |
n.a. |
obj info method definition methodName |
n.a. |
cls ?object? info method definition methodName |
List fully qualified name of method
XOTcl 1 | XOTcl 2 |
n.a. |
obj info method name methodName |
n.a. |
cls ?object? info method name methodName |
List type of a method
XOTcl 1 | XOTcl 2 |
n.a. |
obj info method type methodName |
n.a. |
cls ?object? info method type methodName |
List the scope of mixin classes
XOTcl 1 | XOTcl 2 |
cls info mixinof ?-closure? ?pattern? |
cls info mixinof -scope object ?-closure? ?pattern? |
cls info instmixinof ?-closure? ?pattern? |
cls info mixinof -scope class ?-closure? ?pattern? |
n.a. |
cls info mixinof -scope all ?-closure? ?pattern? |
Check properties of object and classes
XOTcl 1 | XOTcl 2 |
obj istype sometype |
::xotcl::is obj type sometype
obj info is type sometype
|
obj ismixin cls |
::xotcl::is obj mixin cls
obj info is mixin cls
|
obj isclass ?cls? |
::xotcl::is obj|cls class
obj info is class
|
obj ismetaclass cls |
::xotcl::is obj|cls metaclass
obj info is metaclass
|
n.a. |
::xotcl::is cls baseclass
cls info is baseclass
|
obj isobject obj2 |
::xotcl::is obj|obj2 object
obj info is object
|
Predefined Methods
Dispatch, Aliases, etc.
Assertions
XOTcl 1 | XOTcl 2 |
obj check checkptions |
::xotcl::assertion obj check checkptions |
obj info check |
::xotcl::assertion obj check |
obj invar conditions |
::xotcl::assertion obj object-invar conditions |
obj info invar |
::xotcl::assertion obj object-invar |
cls instinvar conditions |
::xotcl::assertion cls class-invar conditions |
cls info instinvar |
::xotcl::assertion cls class-invar |
cls invar conditions |
::xotcl::assertion cls object-invar conditions |
cls info invar |
::xotcl::assertion cls object-invar |
Method Protection
Incompatibilities
Namespace resolvers
The XOTcl 2 namespace resolvers are use as well when XOTcl 1 is used
within XOTcl 2.
Stronger Checking
XOTcl 2 performs stronger checking than XOTcl 1. The requiredness
of slots in XOTcl 1 was just a comment, while XOTcl 2 enforces it.
Different results
[self next]
returns
instead of "proc" and "instproc" => "method"
instead of "parametercmd" and "instparametercmd" => "setter"
instead of "instforward" => "forward"
instead of "instcmd" => "cmd".
The modifier "object" is added when needed.
[self filterreg]
returns
instead of "instforward" => "forward"
The modifier "object" is added when needed.
Exit handlers
The exit hander interface changed from a method of
::xotcl::Object
into procs in the ::xotcl
namespace. XOTcl 2 provides now:
::xotcl::setExitHandler script
::xotcl::getExitHandler
::xotcl::unsetExitHandler
Last modified: Tue Jan 12 11:35:29 CET 2010