# Define method and class-object method
+# Define method and class method
# with separate commands
Class create C
C method foo args {...}
-C class-object method bar args {...}
-The encapsulation of Next Scripting is stronger than in XOTcl but - still weak compared to languages like C++; a developer can still - access e.g. other variables via some idioms, but this makes - accesses to other objects variables explicit and requires more - typing effort. Through the weak encapsulation a programmer should - be encouraged to implement methods to provide access to instance - variables. +The encapsulation of NX is stronger than in XOTcl but still weak + compared to languages like C++; a developer can still access other + objects' variables via some idioms, but NX makes accesses to other + objects variables explicit. The requiredness to make these + accesses explicit should encourage developer to implement well + defined interfaces to provide access to instance variables.
The Next Scripting Language provides means of method - protection. Therefore developers have to define interfaces in order - to use methods from other objects. + protection. Therefore developers have to define interfaces in + order to use methods from other objects.
-The Next Scripting Language has a much smaller interface (less - predefined methods) than XOTcl: +The naming of the methods in the Next Scripting Language is much more + in line with the mainstream naming conventions in OO languages.
--NX: +The Next Scripting Language has a much smaller interface (less + predefined methods) than XOTcl (see Table 1), allthough the + expressability was increased in NX.
-|
-Methods for Objects:
- - |
-
- -18 - - |
++ | NX | +XOTcl |
|---|---|---|---|---|
|
-Methods for Classes:
- - |
-
- -7 - - |
+Total |
+41 |
+125 |
|
-Info methods for Objects:
- - |
-
- -14 - - |
+Methods for Objects |
+17 |
+52 |
|
-Info method for Classes:
- - |
-
- -6 - - |
+Methods for Classes |
+4 |
+24 |
-XOTcl: -
-|
-Methods for Objects:
- - |
-
- -52 - - |
+Info-methods for Objects |
+14 |
+25 |
|
-Methods for Classes:
- - |
-
- -24 - - |
+Info-methods for Classes |
+6 |
+24 |
|
-Info methods for Objects:
- - |
-
- -25 - - |
-|||
|
-Info method for Classes:
- - |
-
- -24 - - |
-
-The naming of the methods in the The Next Scripting Language is much more - in line with the mainstream naming conventions in OO languages. -
-Below is a small, introductory example showing an implementation of a class Stack in NX and XOTcl. NX supports a block syntax, where the methods are defined during the creation of the class. The XOTcl syntax @@ -845,7 +788,7 @@ set things "" } -Stack instproc push {thing} { +Stack instproc push {thing} { my instvar things set things [linsert $things 0 $thing] return $thing @@ -911,21 +854,14 @@ package require XOTcl 2.0 - # Import XOTcl into the current namespace - namespace import -force ::xotcl::* - - # Define a class using XOTcl - Class C1 + # Define a class using XOTcl + xotcl::Class C1 C1 instproc foo {} {puts "hello world"} package require nx - # Import NX into the current namespace; - # "Class" will be after the command "::nx::Class" - namespace import -force ::nx::* - - # Define a class using NX - Class create C2 { + # Define a class using NX + nx::Class create C2 { :public method foo {} {puts "hello world"} } }
Furthermore, both XOTcl and NX distinguish between scripted methods (section 3.2.1) and C-defined methods (section 3.2.2). Section 3.2.3 introduces method protection, which is only supported by NX.
# Define method 'foo' and class-object +# Define method 'foo' and class # method 'bar' for a Class 'C' with separate # toplevel commands @@ -1096,12 +1032,12 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -# Define method and class-object method +# Define method and class method # in the init-block of a class Class create C { :method foo args {...} - :class-object method bar args {...} + :class method bar args {...} }+C class method bar args {...}-# Define method and class-object method +# Define method and class method # with separate commands Class create C C method foo args {...} -C class-object method bar args {...}@@ -2190,7 +2141,7 @@ Class create C { :attribute x :attribute {y 1} - :class-object attribute oa1 + :class attribute oa1 } Object create o { @@ -2568,7 +2519,10 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} - # Define class-object method and set +# Define class method and set # instance variable in the init-block of # an object @@ -1169,7 +1105,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -# Define class-object method and set +# Define class method and set # instance variable with separate # commands @@ -1300,7 +1236,7 @@Class create C { :forward f1 ... - :class-object forward f2 ... + :class forward f2 ... } Object create o { @@ -1319,7 +1255,11 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -Class C +# Define setter and getter methods in XOTcl. +# +# XOTcl provides methods for these. + +Class C C instparametercmd p1 C parametercmd p2 @@ -1336,7 +1276,12 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -# Define setter and getter methods +# Define setter and getter methods in NX. +# +# NX does not provide own methods, but uses +# the low level framework commands, since +# application developer will only seldomly +# need it. Class create C ::nsf::method::setter C p1 @@ -1397,7 +1342,7 @@Class create C { :alias a1 ... - :class-object alias a2 ... + :class alias a2 ... } Object create o { @@ -1410,10 +1355,10 @@3.2.3. Method Modifiers and Method Protection
-NX supports the three method modifiers class-object, public and +
NX supports the three method modifiers class, public and protected. All method modifiers can be written in front of every method -defining command. The method modifier class-object is used to denote -class-object specific methods (see above). The concept of method +defining command. The method modifier class is used to denote +class-specific methods (see above). The concept of method protection is new in NX.
-
# Method modifiers # -# "class-object", +# "class", # "public", and # "protected" # @@ -1459,31 +1404,37 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -# Method modifiers orthogonal over all kinds of methods +# Method modifiers # -# Method-definition-methods: +# "class", +# "public", and +# "protected" +# +# are applicable for all kinds of method +# defining methods: +# # method, forward, alias, attribute Class create C { :/method-definiton-method/ ... :public /method-definiton-method/ ... :protected /method-definiton-method/ ... - :class-object /method-definiton-method/ ... - :protected class-object /method-definiton-method/ ... - :public class-object /method-definiton-method/ ... + :class /method-definiton-method/ ... + :protected class /method-definiton-method/ ... + :public class /method-definiton-method/ ... }-While XOTcl does not provide method protection, in NX, all methods are -defined per default as protected.
+NX allows to configure the default call protection in various -ways. The command ::nx::configure defaultMethodCallProtection -true|false can be used to set the default call protection for -scripted methods, forwarder and aliases, while ::nx::configure -defaultAttributeCallProtection true|false can set the default -protection for attributes.
XOTcl does not provide method protection. In NX, all methods are +defined per default as protected. These defaults can be changed by the +application developer in various ways. The command ::nx::configure +defaultMethodCallProtection true|false can be used to set the default +call protection for scripted methods, forwarder and aliases, while +::nx::configure defaultAttributeCallProtection true|false can set +the default protection for attributes. The defaults can be overwritten +also e.g. on a class level.
@@ -1557,7 +1508,7 @@ } } Object create o { - :method baz {} {...} + :public method baz {} {...} }# n.a.+# Only leading non-positional parameters +# are available; no optional positional +# parameters, no value constraints on +# positional parameters, no multiplicity, ...+ -# n.a.# No return value checking available+/cls/ instmixinguard /mixin/ ?condition? /cls/ instmixin ... -/cls/ instmixinguard mixin /condition/+/cls/ mixin guard /mixin/ ?condition? /cls/ mixin ... -/cls/ mixin guard mixin /condition/
/obj/ mixin ... -/obj/ mixinguard mixin /condition/
/cls/ instfilter ... -/cls/ instfilterguard filter /condition/
/obj/ filter ... -/obj/ filterguard filter /condition/
/cls/ class-object info methods ?pattern?
/cls/ class info methods ?pattern?
/cls/ class-object info methods -methodtype setter ?pattern?
/cls/ class info methods -methodtype setter ?pattern?
/cls/ class-object info methods -methodtype scripted ?pattern?
/cls/ class info methods -methodtype scripted ?pattern?
/cls/ class-object info methods -methodtype alias ?pattern?
/cls/ class info methods -methodtype alias ?pattern?
/cls/ class-object info methods -methodtype forwarder ?pattern?
/cls/ class info methods -methodtype forwarder ?pattern?
/cls/ class-object info methods -methodtype object ?pattern?
/cls/ class info methods -methodtype object ?pattern?
/cls/ class-object info methods \ +/cls/ class info methods \ -callprotection public|protected ...
/cls/ ?class-object? info method exists /methodName/ -/cls/ ?class-object? info methods /methodName/+
/cls/ ?class? info method exists /methodName/ +/cls/ ?class? info methods /methodName/@@ -4337,7 +4294,7 @@
For definition of class object specific methods, use the modifier -class-object as shown in examples above.
/cls/ class-object info filter methods \ +/cls/ class info filter methods \ ?-guards? ?-order? ?pattern?
/cls/ class-object info filter guard /name/+
/cls/ class info filter guard /name/
/cls/ class-object info mixin classes \ +/cls/ class info mixin classes \ ?-guards? ?-order? ?pattern?
/cls/ class-object info mixin guard /name/+
/cls/ class info mixin guard /name/
As mentioned earlier, +info method definition" can be used on every +
As mentioned earlier, info method definition can be used on every kind of method.
/cls/ ?class-object? info method type /methodName/
/cls/ ?class? info method type /methodName/
In XOTcl 1, it was possible to call a parameter method during object -creation via the -param without a value (in the example below -x.
Class Foo -parameter {x y} +# XOTcl example + +Class Foo -parameter {x y} Foo f1 -x -y 1
Such cases are most likely mistakes. All parameter configurations in XOTcl 2 require an argument.
Class Foo -parameter {{x 1}} +# XOTcl example + +Class Foo -parameter {{x 1}} Class Bar -superclass Foo -parameter x Bar b1+++4.2.3. Ignored Parameter definitions
++NX does not define the methods class and superclass but allows to +alter the class/superclass via configure. The class and superclass +can be certainly queried in all variants with info class or info superclass.
++# NX example + +nx::Class create Foo +Foo create f1 +# now oalter the class of object f1 +f1 configure -class nx::Object4.3. Calling Objects via Method Interface
Since the Next Scripting Framework supports the so-called ensemble @@ -5980,7 +5964,9 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
Foo::slot::ints foo ... +# XOTcl example + +Foo::slot::ints foo ... Foo slot ints foo ...+In the Next Scripting Framework, only the first form has the same semantic as before. In the second form (invocation of objects via @@ -6022,16 +6008,17 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
::nsf::exithandler set|get|unset ?arg?# NX example +::nsf::exithandler set|get|unset ?arg?