Index: doc/next-tutorial/next-tutorial.html =================================================================== diff -u -rd8b8fec1b9c4b2ab7c1cc36c156649109ca0807a -rd303212e06bfd89c57038a26ba54f9f86e941601 --- doc/next-tutorial/next-tutorial.html (.../next-tutorial.html) (revision d8b8fec1b9c4b2ab7c1cc36c156649109ca0807a) +++ doc/next-tutorial/next-tutorial.html (.../next-tutorial.html) (revision d303212e06bfd89c57038a26ba54f9f86e941601) @@ -858,44 +858,25 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Stack {
+
nx::Class create Stack {
 
-   #
-   # Stack of Things
-   #
+   #
+   # Stack of Things
+   #
 
    :variable things {}
 
    :public method push {thing} {
-      set :things [linsert ${:things} 0 $thing]
-      return $thing
+      set :things [linsert ${:things} 0 $thing]
+      return $thing
    }
 
    :public method pop {} {
-      set top [lindex ${:things} 0]
-      set :things [lrange ${:things} 1 end]
-      return $top
+      set top [lindex ${:things} 0]
+      set :things [lrange ${:things} 1 end]
+      return $top
    }
-}
+}

Typically, classes are defined in NX via nx::Class create, followed by the name of the new class (here: Stack). The definition of the stack placed between curly braces and contains here just the method @@ -952,32 +933,14 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#!/usr/bin/env tclsh
+
#!/usr/bin/env tclsh
 package require nx
 
 nx::Class create Stack {
 
-   #
-   # Stack of Things
-   #
+   #
+   # Stack of Things
+   #
    ....
 }
 
@@ -987,7 +950,7 @@
 s1 push c
 puts [s1 pop]
 puts [s1 pop]
-s1 destroy

+s1 destroy

Now we want to use the stack. The code snippet in Listing 3 shows how to use the class Stack in a script. Since NX is based on Tcl, the script will be called with the Tcl shell tclsh. In the Tcl shell we have to require package nx to use the @@ -1051,36 +1014,21 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Object create stack {
+
nx::Object create stack {
 
    :object variable things {}
 
    :public object method push {thing} {
-      set :things [linsert ${:things} 0 $thing]
-      return $thing
+      set :things [linsert ${:things} 0 $thing]
+      return $thing
    }
 
    :public object method pop {} {
-      set top [lindex ${:things} 0]
-      set :things [lrange ${:things} 1 end]
-      return $top
+      set top [lindex ${:things} 0]
+      set :things [lrange ${:things} 1 end]
+      return $top
    }
-}

+}

The example in Listing 5 defines the object stack in a very similar way as the class Stack. But the following points are different.

@@ -1158,40 +1106,16 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Safety {
+
nx::Class create Safety {
 
-  #
-  # Implement stack safety by defining an additional
-  # instance variable named "count" that keeps track of
-  # the number of stacked elements. The methods of
-  # this class have the same names and argument lists
-  # as the methods of Stack; these methods "shadow"
-  # the methods of class Stack.
-  #
+  #
+  # Implement stack safety by defining an additional
+  # instance variable named "count" that keeps track of
+  # the number of stacked elements. The methods of
+  # this class have the same names and argument lists
+  # as the methods of Stack; these methods "shadow"
+  # the methods of class Stack.
+  #
 
   :variable count 0
 
@@ -1201,11 +1125,11 @@
   }
 
   :public method pop {} {
-    if {${:count} == 0} then { error "Stack empty!" }
+    if {${:count} == 0} then { error "Stack empty!" }
     incr :count -1
     next
   }
-}
+}

Note that all the methods of the class Safety end with next. This command is a primitive command of NX, which calls the same-named method with the same argument list as the current @@ -1230,29 +1154,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
% package require nx
+
% package require nx
 2.0
 % source Stack.tcl
 ::Stack
@@ -1273,7 +1175,7 @@
 ::Stack ::nx::Object
 
 % s2 info precedence
-::Safety ::Stack ::nx::Object

+::Safety ::Stack ::nx::Object

When the method push of s2 is called, first the method of the mixin class Safety will be invoked that increments the counter and continues with next to call the shadowed method, here the method @@ -1318,20 +1220,13 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Create a safe stack class by using Stack and mixin
-# Safety
-#
+
#
+# Create a safe stack class by using Stack and mixin
+# Safety
+#
 nx::Class create SafeStack -superclass Stack -mixin Safety
 
-SafeStack create s3

+SafeStack create s3

The difference of a per-class mixin and an per-object mixin is that the per-class mixin is applicable to all instances of the class. Therefore, we call these mixins also sometimes instance mixins. @@ -1373,28 +1268,17 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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Stack create s4 {
+
Stack create s4 {
 
-  #
-  # Create a stack with a object-specific method
-  # to check the type of entries
-  #
+  #
+  # Create a stack with a object-specific method
+  # to check the type of entries
+  #
 
   :public object method push {thing:integer} {
     next
   }
-}

+}

The program snippet in Listing 12 defines an instance s4 of the class Stack and provides an object specific method for push to implement an integer stack. The method pull is the same for the integer stack @@ -1420,26 +1304,16 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Class create IntegerStack -superclass Stack {
+
nx::Class create IntegerStack -superclass Stack {
 
-  #
-  # Create a Stack accepting only integers
-  #
+  #
+  # Create a Stack accepting only integers
+  #
 
   :public method push {thing:integer} {
     next
   }
-}

+}

An alternative approach is shown in Listing 13, where the class IntegerStack is defined, using the same method definition @@ -1473,31 +1347,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Stack2 {
+
nx::Class create Stack2 {
 
    :public object method available_stacks {} {
       return [llength [:info instances]]
@@ -1506,21 +1356,21 @@
    :variable things {}
 
    :public method push {thing} {
-      set :things [linsert ${:things} 0 $thing]
-      return $thing
+      set :things [linsert ${:things} 0 $thing]
+      return $thing
    }
 
    :public method pop {} {
-      set top [lindex ${:things} 0]
-      set :things [lrange ${:things} 1 end]
-      return $top
+      set top [lindex ${:things} 0]
+      set :things [lrange ${:things} 1 end]
+      return $top
    }
 }
 
 Stack2 create s1
 Stack2 create s2
 
-puts [Stack2 available_stacks]

+puts [Stack2 available_stacks]

The class Stack2 in Listing 14 consists of the earlier definition of the class Stack and is extended by the class-specific method available_stacks, which returns the @@ -1591,28 +1441,17 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Class create Foo {
+
nx::Class create Foo {
 
   :method foo args {...}
-    # "a" is a method scoped variable
+    # "a" is a method scoped variable
     set a 1
-    # "b" is an Instance variable
+    # "b" is an Instance variable
     set :b 2
-    # "c" is a global variable/namespaced variable
+    # "c" is a global variable/namespaced variable
     set ::c 3
   }
-}

+}

Listing 16 shows a method foo of some class Foo referring to differently scoped variables.

@@ -1662,60 +1501,33 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Define a class Person with properties "name"
-# and "birthday"
-#
+
#
+# Define a class Person with properties "name"
+# and "birthday"
+#
 nx::Class create Person {
   :property name:required
   :property birthday
 }
 
-#
-# Define a class Student as specialization of Person
-# with additional properties
-#
+#
+# Define a class Student as specialization of Person
+# with additional properties
+#
 nx::Class create Student -superclass Person {
   :property matnr:required
   :property {oncampus:boolean true}
 }
 
-#
-# Create instances using configure parameters
-# for the initialization
-#
+#
+# Create instances using configure parameters
+# for the initialization
+#
 Person create p1 -name Bob
 Student create s1 -name Susan -matnr 4711
 
-# Access property value via accessor method
-puts "The name of s1 is [s1 cget -name]"
+# Access property value via accessor method +puts "The name of s1 is [s1 cget -name]"

By defining name and birthday as properties of Person, NX makes these configurable. When we create an instance of Person named p1, we can provide a value for e.g. the name by specifying -name @@ -1772,36 +1584,21 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Base {
+
nx::Class create Base {
   :variable x 1
-  # ...
+  # ...
 }
 
 nx::Class create Derived -superclass Base {
   :variable y 2
-  # ...
+  # ...
 }
 
-# Create instance of the class Derived
+# Create instance of the class Derived
 Derived create d1
 
-# Object d1 has instance variables
-# x == 1 and y == 2

+# Object d1 has instance variables +# x == 1 and y == 2

Note that the variable definitions are inherited in the same way as properties. The example in Listing 19 shows a class Derived that inherits from Base. When an instance d1 is @@ -1820,44 +1617,25 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Base2 {
- # ...
+
nx::Class create Base2 {
+ # ...
  :method init {} {
    set :x 1
-   # ....
+   # ....
  }
 }
 
 nx::Class create Derived2 -superclass Base2 {
- # ...
+ # ...
  :method init {} {
    set :y 2
    next
-   # ....
+   # ....
  }
 }
 
-# Create instance of the class Derived2
-Derived2 create d2

+# Create instance of the class Derived2 +Derived2 create d2

In many other object oriented languages, the instance variables are initialized solely by the constructor (similar to class Derived2 in Listing 20). This approach is certainly @@ -1904,34 +1682,20 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
# Define a class
+
# Define a class
 nx::Class create Dog {
 
-  # Define a scripted method for the class
+  # Define a scripted method for the class
   :public method bark {} {
     puts "[self] Bark, bark, bark."
   }
 }
 
-# Create an instance of the class
+# Create an instance of the class
 Dog create fido
 
-# The following line prints "::fido Bark, bark, bark."
-fido bark

+# The following line prints "::fido Bark, bark, bark." +fido bark

In the example above we create a class Dog with a scripted method named bark. The method body defines the code, which is executed when the method is invoked. In this example, the method bar prints out a @@ -1980,32 +1744,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Dog {
+
nx::Class create Dog {
  :public method bark {} { puts "[self] Bark, bark, bark." }
  :method init {} { Tail create [self]::tail}
 }
@@ -2015,21 +1754,21 @@
   :public method wag {} {return Joy}
 }
 
-# Create an instance of the class
+# Create an instance of the class
 Dog create fido
 
-# Use the accessor "length" as a getter, to obtain the value
-# of a property. The following call returns the length of the
-# tail of fido
+# Use the accessor "length" as a getter, to obtain the value
+# of a property. The following call returns the length of the
+# tail of fido
 fido::tail length get
 
-# Use the accessor "length" as a setter, to alter the value
-# of a property. The following call changes the length of
-# the tail of fido
+# Use the accessor "length" as a setter, to alter the value
+# of a property. The following call changes the length of
+# the tail of fido
 fido::tail length set 10
 
-# Proving an invalid values will raise an error
-fido::tail length set "Hello"

+# Proving an invalid values will raise an error +fido::tail length set "Hello"

Listing 22 shows an extended example, where every dog has a tail. The object tail is created as a subobject of the dog in the constructor init. The subobject can be accessed by providing the @@ -2050,26 +1789,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Dog {
+
nx::Class create Dog {
   :public method bark {} { puts "[self] Bark, bark, bark." }
   :method init {} {
     Tail create [self]::tail
@@ -2082,12 +1802,12 @@
   :public method wag {} {return Joy}
 }
 
-# Create an instance of the class
+# Create an instance of the class
 Dog create fido
 
-# The invocation of "fido wag" is delegated to "fido::tail wag".
-# Therefore, the following method returns "Joy".
-fido wag

+# The invocation of "fido wag" is delegated to "fido::tail wag". +# Therefore, the following method returns "Joy". +fido wag

Listing 23 again extends the example by adding a forwarder named wag to the object (e.g. fido). The forwarder redirects all calls of the form fido wag with arbitrary arguments to @@ -2133,32 +1853,19 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Dog {
+
nx::Class create Dog {
   :public method bark {} { puts "[self] Bark, bark, bark." }
 
-  # Define a public alias for the method "bark"
+  # Define a public alias for the method "bark"
   :public alias warn [:info method handle bark]
-  # ...
+  # ...
 }
 
-# Create an instance of the class
+# Create an instance of the class
 Dog create fido
 
-# The following line prints "::fido Bark, bark, bark."
-fido warn

+# The following line prints "::fido Bark, bark, bark." +fido warn

Listing 24 extends the last example by defining an alias for the method bark. The example only shows the bare mechanism. In general, method aliases are very powerful means for @@ -2206,50 +1913,28 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Foo {
+
nx::Class create Foo {
 
-  # Define a public method
+  # Define a public method
   :public method foo {} {
-    # ....
+    # ....
     return [:helper]
   }
 
-  # Define a protected method
+  # Define a protected method
   :method helper {} {
      return 1
   }
 }
 
-# Create an instance of the class:
+# Create an instance of the class:
 Foo create f1
 
-# The invocation of the public method "foo" returns 1
+# The invocation of the public method "foo" returns 1
 f1 foo
 
-# The invocation of the protected method "helper" raises an error:
-f1 helper

+# The invocation of the protected method "helper" raises an error: +f1 helper

The example above uses :protected method helper …. We could have used here as well :method helper …, since the default method call-protection is already protected.

@@ -2269,34 +1954,20 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create Base {
-  :private method helper {a b} {expr {$a + $b}}
-  :public method foo     {a b} {: -local helper $a $b}
+
nx::Class create Base {
+  :private method helper {a b} {expr {$a + $b}}
+  :public method foo     {a b} {: -local helper $a $b}
 }
 
 nx::Class create Sub -superclass Base {
-  :public method bar     {a b} {: -local helper $a $b}
-  :private method helper {a b} {expr {$a * $b}}
+  :public method bar     {a b} {: -local helper $a $b}
+  :private method helper {a b} {expr {$a * $b}}
   :create s1
 }
 
-s1 foo 3 4     ;# returns 7
-s1 bar 3 4     ;# returns 12
-s1 helper 3 4  ;# raises error: unable to dispatch method helper
+s1 foo 3 4 ;# returns 7 +s1 bar 3 4 ;# returns 12 +s1 helper 3 4 ;# raises error: unable to dispatch method helper

The base class implements a public method foo using the helper method named helper. The derived class implements a as well a public method bar, which is also using a helper method named helper. When @@ -2335,56 +2006,31 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Define a class C with a property "x" and a public accessor
-#
+
#
+# Define a class C with a property "x" and a public accessor
+#
 nx::Class create C {
   :property -accessor public {x c}
 }
 
-#
-# Define a subclass D with a private property "x"
-# and a method bar, which is capable of accessing
-# the private property.
-#
+#
+# Define a subclass D with a private property "x"
+# and a method bar, which is capable of accessing
+# the private property.
+#
 nx::Class create D -superclass C {
   :property -accessor private {x d}
-  :public method bar {p} {return [: -local $p get]}
+  :public method bar {p} {return [: -local $p get]}
 }
 
-#
-# The private and public (or protected) properties
-# define internally separate variable that do not
-# conflict.
-#
+#
+# The private and public (or protected) properties
+# define internally separate variable that do not
+# conflict.
+#
 D create d1
-puts [d1 x get]   ;# prints "c"
-puts [d1 bar x]   ;# prints "d"

+puts [d1 x get] ;# prints "c" +puts [d1 bar x] ;# prints "d"

Without the private definition of the property, the definition of property x in class D would shadow the definition of the property in the superclass C for its instances @@ -2417,22 +2063,14 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Class create C {
+
nx::Class create C {
   :public method foo {} {return 1}
   :create c1
 }
 
-# Method "foo" is defined on class "C"
-# and applicable to the instances of "C"
-c1 foo

+# Method "foo" is defined on class "C" +# and applicable to the instances of "C" +c1 foo

There are many programming languages that only allow these types of methods. However, NX also allows methods to be defined on objects.

@@ -2462,44 +2100,25 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Class create C {
+
nx::Class create C {
   :public method foo {} {return 1}
   :create c1 {
      :public object method foo {} {return 2}
      :public object method bar {} {return 3}
   }
 }
 
-# Method "bar" is an object specific method of "c1"
+# Method "bar" is an object specific method of "c1"
 c1 bar
 
-# object-specific method "foo" returns 2
+# object-specific method "foo" returns 2
 c1 foo
 
-# Method "baz" is an object specific method of "o1"
+# Method "baz" is an object specific method of "o1"
 nx::Object create o1 {
   :public object method baz {} {return 4}
 }
-o1 baz
+o1 baz

3.4.3. Class Methods

@@ -2529,56 +2148,31 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create C {
-  #
-  # Define a class method "bar" and an instance
-  # method "foo"
-  #
+
nx::Class create C {
+  #
+  # Define a class method "bar" and an instance
+  # method "foo"
+  #
   :public object method bar {} {return 2}
   :public method foo {} {return 1}
 
-  #
-  # Create an instance of the current class
-  #
+  #
+  # Create an instance of the current class
+  #
   :create c1
 }
 
-# Method "bar" is a class method of class "C"
-# therefore applicable on the class object "C"
+# Method "bar" is a class method of class "C"
+# therefore applicable on the class object "C"
 C bar
 
-# Method "foo" is an instance method of "C"
-# therefore applicable on instance "c1"
+# Method "foo" is an instance method of "C"
+# therefore applicable on instance "c1"
 c1 foo
 
-# When trying to invoke the class method on the
-# instance, an error will be raised.
-c1 bar
+# When trying to invoke the class method on the +# instance, an error will be raised. +c1 bar

In some other object oriented programming languages, class methods are called "static methods".

@@ -2614,34 +2208,20 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Class create C {
+
nx::Class create C {
 
-    # Define an ensemble method "string" with sub-methods
-    # "length", "tolower" and "info"
+    # Define an ensemble method "string" with sub-methods
+    # "length", "tolower" and "info"
 
     :public method "string length"  {x} {....}
     :public method "string tolower" {x} {...}
     :public method "string info" {x} {...}
-    #...
+    #...
     :create c1
 }
 
-# Invoke the ensemble method
-c1 string length "hello world"
+# Invoke the ensemble method +c1 string length "hello world"

3.6. Method Resolution

@@ -2665,33 +2245,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create C {
+
nx::Class create C {
   :public method foo {} {
     return "C foo: [next]"
   }
@@ -2710,13 +2264,13 @@
    }
 }
 
-# Invoke the method foo
+# Invoke the method foo
 d1 foo
-# result: "d1 foo: D foo: C foo: "
+# result: "d1 foo: D foo: C foo: "
 
-# Query the precedence order from NX via introspection
+# Query the precedence order from NX via introspection
 d1 info precedence
-# result: "::D ::C ::nx::Object"
+# result: "::D ::C ::nx::Object"

Consider the example in Listing 32. When the method foo is invoked on object d1, the object method has the highest @@ -2744,54 +2298,30 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Class create M1 {
+
nx::Class create M1 {
   :public method foo {} { return "M1 foo: [next]"}
 }
 nx::Class create M2 {
   :public method foo {} { return "M2 foo: [next]"}
 }
 
-#
-# "d1" is created based on the definitions of the last example
-#
-# Add the methods from "M1" as per-object mixin to "d1"
+#
+# "d1" is created based on the definitions of the last example
+#
+# Add the methods from "M1" as per-object mixin to "d1"
 d1 object mixins add M1
 
-#
-# Add the methods from "M2" as per-class mixin to class "C"
+#
+# Add the methods from "M2" as per-class mixin to class "C"
 C mixins add M2
 
-# Invoke the method foo
+# Invoke the method foo
 d1 foo
-# result: "M1 foo: M2 foo: d1 foo: D foo: C foo: "
+# result: "M1 foo: M2 foo: d1 foo: D foo: C foo: "
 
-# Query the precedence order from NX via introspection
+# Query the precedence order from NX via introspection
 d1 info precedence
-# result: "::M1 ::M2 ::D ::C ::nx::Object"

+# result: "::M1 ::M2 ::D ::C ::nx::Object"

The example in Listing 33 is an extension of the previous example. We define here two additional classes M1 and M2 which are used as per-object and per-class @@ -2811,38 +2341,22 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# "d1" is created based on the definitions of the last two examples,
-# the mixins "M1" and "M2" are registered.
-#
-# Define a public object method "bar", which calls the method
-# "foo" which various invocation options:
-#
+
#
+# "d1" is created based on the definitions of the last two examples,
+# the mixins "M1" and "M2" are registered.
+#
+# Define a public object method "bar", which calls the method
+# "foo" which various invocation options:
+#
 d1 public object method bar {} {
    puts [:foo]
    puts [: -local foo]
    puts [: -intrinsic foo]
    puts [: -system foo]
 }
 
-# Invoke the method "bar"
-d1 bar

+# Invoke the method "bar" +d1 bar

In the first line of the body of method bar, the method foo is called as usual with an implicit receiver, which defaults to the current object (therefore, the call is equivalent to d1 foo). The @@ -2935,78 +2449,42 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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- 36
-
nx::Object create o1 {
+
nx::Object create o1 {
 
-  #
-  # Method foo has positional parameters:
-  #
+  #
+  # Method foo has positional parameters:
+  #
   :public object method foo {x y} {
     puts "x=$x y=$y"
   }
 
-  #
-  # Method bar has non-positional parameters:
-  #
+  #
+  # Method bar has non-positional parameters:
+  #
   :public object method bar {-x -y} {
     puts "x=$x y=$y"
   }
 
-  #
-  # Method baz has non-positional and
-  # positional parameters:
-  #
+  #
+  # Method baz has non-positional and
+  # positional parameters:
+  #
   :public object method baz {-x -y a} {
     puts "x? [info exists x] y? [info exists y] a=$a"
   }
 }
 
-# invoke foo (positional parameters)
+# invoke foo (positional parameters)
 o1 foo 1 2
 
-# invoke bar (non-positional parameters)
+# invoke bar (non-positional parameters)
 o1 bar -y 3 -x 1
 o1 bar -x 1 -y 3
 
-# invoke baz (positional and non-positional parameters)
+# invoke baz (positional and non-positional parameters)
 o1 baz -x 1 100
 o1 baz 200
-o1 baz -- -y

+o1 baz -- -y

Consider the example in Listing 35. The method foo has the argument list x y. This means that the first argument is passed in an invocation like o1 foo 1 2 to x (here, the value @@ -3052,48 +2530,27 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Object create o2 {
+
nx::Object create o2 {
 
-  #
-  # Method foo has one required and one optional
-  # positional parameter:
-  #
+  #
+  # Method foo has one required and one optional
+  # positional parameter:
+  #
   :public object method foo {x:required y:optional} {
     puts "x=$x y? [info exists y]"
   }
 
-  #
-  # Method bar has one required and one optional
-  # non-positional parameter:
-  #
+  #
+  # Method bar has one required and one optional
+  # non-positional parameter:
+  #
   :public object method bar {-x:required -y:optional} {
     puts "x=$x y? [info exists y]"
   }
 }
 
-# invoke foo (one optional positional parameter is missing)
-o2 foo 1

+# invoke foo (one optional positional parameter is missing) +o2 foo 1

The example in Listing 36 defined method foo with one required and one optional positional parameter. For this purpose we use the parameter options required and optional. The @@ -3131,46 +2588,26 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Object create o3 {
+
nx::Object create o3 {
 
-  #
-  # Positional parameter with default value:
-  #
+  #
+  # Positional parameter with default value:
+  #
   :public object method foo {{x 1} {y 2}} {
     puts "x=$x y=$y"
   }
 
-  #
-  # Non-positional parameter with default value:
-  #
+  #
+  # Non-positional parameter with default value:
+  #
   :public object method bar {{-x 10} {-y 20}} {
     puts "x=$x y=$y"
   }
 }
 
-# use default values
+# use default values
 o3 foo
-o3 bar

+o3 bar

In order to define a default value for a parameter, the parameter specification must be of the form of a 2 element list, where the second argument is the default value. See for an example in @@ -3221,46 +2658,26 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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nx::Object create o4 {
+
nx::Object create o4 {
 
-  #
-  # Positional parameter with value constraints:
-  #
+  #
+  # Positional parameter with value constraints:
+  #
   :public object method foo {x:integer o:object,optional} {
     puts "x=$x o? [info exists o]"
   }
 
-  #
-  # Non-positional parameter with value constraints:
-  #
+  #
+  # Non-positional parameter with value constraints:
+  #
   :public object method bar {{-x:integer 10} {-verbose:boolean false}} {
     puts "x=$x verbose=$verbose"
   }
 }
 
-# The following invocation raises an exception, since the
-# value "a" for parameter "x" is not an integer
-o4 foo a

+# The following invocation raises an exception, since the +# value "a" for parameter "x" is not an integer +o4 foo a

Value contraints are specified as parameter options in the parameter specifications. The parameter specification x:integer defines x as a required positional parmeter which value is constraint to an @@ -3282,62 +2699,34 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Create classes for Person and Project
-#
+
#
+# Create classes for Person and Project
+#
 nx::Class create Person
 nx::Class create Project
 
 nx::Object create o5 {
-  #
-  # Parameterized value constraints
-  #
+  #
+  # Parameterized value constraints
+  #
   :public object method work {
      -person:object,type=Person
      -project:object,type=Project
    } {
-    # ...
+    # ...
   }
 }
 
-#
-# Create a Person and a Project instance
-#
+#
+# Create a Person and a Project instance
+#
 Person create gustaf
 Project create nx
 
-#
-# Use method with value constraints
-#
-o5 work -person gustaf -project nx

+# +# Use method with value constraints +# +o5 work -person gustaf -project nx

The native checkers object, class, metaclass and baseclass can be further specialized with the parameter option type to restrict the permissible values to instances of certain classes. We can use for @@ -3371,92 +2760,49 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Value checker named "groupsize"
-#
+
#
+# Value checker named "groupsize"
+#
 ::nx::Slot method type=groupsize {name value} {
-  if {$value < 1 || $value > 6} {
+  if {$value < 1 || $value > 6} {
     error "Value '$value' of parameter $name is not between 1 and 6"
   }
 }
 
-#
-# Value checker named "choice" with extra argument
-#
+#
+# Value checker named "choice" with extra argument
+#
 ::nx::Slot method type=choice {name value arg} {
-  if {$value ni [split $arg |]} {
+  if {$value ni [split $arg |]} {
     error "Value '$value' of parameter $name not in permissible values $arg"
   }
 }
 
-#
-# Create an application class D
-# using the new value checkers
-#
+#
+# Create an application class D
+# using the new value checkers
+#
 nx::Class create D {
   :public method foo {a:groupsize} {
-    # ...
+    # ...
   }
   :public method bar {a:choice,arg=red|yellow|green b:choice,arg=good|bad} {
-    # ...
+    # ...
   }
 }
 
 D create d1
 
-# testing "groupsize";
-# the second call (with value 10) will raise an exception:
+# testing "groupsize";
+# the second call (with value 10) will raise an exception:
 d1 foo 2
 d1 foo 10
 
-# testing "choice"
-# the second call (with value pink for parameter a)
-# will raise an exception:
+# testing "choice"
+# the second call (with value pink for parameter a)
+# will raise an exception:
 d1 bar green good
-d1 bar pink bad

+d1 bar pink bad

In order to define a checker groupsize a method of the name type=groupsize is defined. This method receives two arguments, name and value. The first argument is the name of the parameter @@ -3514,58 +2860,32 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
nx::Object create o6 {
+
nx::Object create o6 {
 
-  #
-  # Positional parameter with an possibly empty
-  # single value
-  #
+  #
+  # Positional parameter with an possibly empty
+  # single value
+  #
   :public object method foo {x:integer,0..1} {
     puts "x=$x"
   }
 
-  #
-  # Positional parameter with an possibly empty
-  # list of values value
-  #
+  #
+  # Positional parameter with an possibly empty
+  # list of values value
+  #
   :public object method bar {x:integer,0..n} {
     puts "x=$x"
   }
 
-  #
-  # Positional parameter with a non-empty
-  # list of values
-  #
+  #
+  # Positional parameter with a non-empty
+  # list of values
+  #
   :public object method baz {x:integer,1..n} {
     puts "x=$x"
   }
-}

+}

Listing 42 contains three examples for positional parameters with different multiplicities. Multiplicity is often combined with value constraints. A parameter specification of @@ -3654,60 +2974,33 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
#
-# Define a class Person with properties "name"
-# and "birthday"
-#
+
#
+# Define a class Person with properties "name"
+# and "birthday"
+#
 nx::Class create Person {
   :property name:required
   :property birthday
 }
 
-#
-# Define a class Student as specialization of Person
-# with and additional property
-#
+#
+# Define a class Student as specialization of Person
+# with and additional property
+#
 nx::Class create Student -superclass Person {
   :property matnr:required
   :property {oncampus:boolean true}
 }
 
-#
-# Create instances using configure parameters
-# for the initialization
-#
+#
+# Create instances using configure parameters
+# for the initialization
+#
 Person create p1 -name Bob
 Student create s1 -name Susan -matnr 4711
 
-# Access property value via "cget" method
-puts "The name of s1 is [s1 cget -name]"

+# Access property value via "cget" method +puts "The name of s1 is [s1 cget -name]"

The class Person has two properties name and birthday, where the property name is required, the property birthday is not. The class Student is a subclass of Person with the additional required @@ -3764,21 +3057,7 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
Configure parameters for Person p1:
+
Configure parameters for Person p1:
    Command:
       p1 info lookup syntax configure
    Result:
@@ -3791,7 +3070,7 @@
    Result:
       ?-oncampus /boolean/? -matnr /value/ -name /value/
       ?-birthday /value/? ?-object-mixins /mixinreg .../? ?-class /class/?
-      ?-object-filters /filterreg .../? ?/__initblock/?

+ ?-object-filters /filterreg .../? ?/__initblock/?

The given paramter show, how (a) objects can be configured at runtime or (b) how new instances can be configured at creation time via the new or create methods. @@ -3848,20 +3127,13 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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Configure parameter for class nx::Class
+
Configure parameter for class nx::Class
    Command:
       nx::Class info lookup syntax configure
    Result:
       ?-superclass /class .../? ?-mixins /mixinreg .../?
       ?-filters /filterreg .../? ?-object-mixins /mixinreg .../?
-      ?-class /class/? ?-object-filters /filterreg .../? ?/__initblock/?

+ ?-class /class/? ?-object-filters /filterreg .../? ?/__initblock/?

4.3.3. User defined Parameter Types

@@ -3962,26 +3234,16 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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- 10
-
::nx::Object create o {
+
::nx::Object create o {
   :object method unknown {called_method args} {
     puts "Unknown method '$called_method' called"
   }
 }
 
-# Invoke an unknown method for object o:
+# Invoke an unknown method for object o:
 o foo 1 2 3
 
-# Output will be: "Unknown method 'foo' called"
+# Output will be: "Unknown method 'foo' called"

Without any provision of an unknown method handler, an error will be raised, when an unknown method is called.

@@ -4006,50 +3268,28 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
::nx::Class public object method __unknown {name} {
-  # A very simple unknown handler, showing just how
-  # the mechanism works.
+
::nx::Class public object method __unknown {name} {
+  # A very simple unknown handler, showing just how
+  # the mechanism works.
   puts "***** __unknown called with <$name>"
-  ::nx::Class create $name
+  ::nx::Class create $name
 }
 
-# Register an unknown handler as a method of ::nx::Class
+# Register an unknown handler as a method of ::nx::Class
 ::nsf::object::unknown::add nx {::nx::Class __unknown}
 
 ::nx::Object create o {
-  # The class M is unknown at this point
+  # The class M is unknown at this point
 
   :object mixins add M
-  # The line above has triggered the unknown class handler,
-  # class M is now defined
+  # The line above has triggered the unknown class handler,
+  # class M is now defined
 
   puts [:info object mixins]
-  # The output will be:
-  #     ***** __unknown called with <::M>
-  #     ::M
-}
+ # The output will be: + # ***** __unknown called with <::M> + # ::M +}

The Next Scripting Framework allows to add, query, delete and list unknown handlers.

Listing 50: Unknown Handler registration

@@ -4063,16 +3303,11 @@ .nx-placeholder {color: #AF663F; font-weight: normal; font-style: italic;} .nx-variable {color: #AF663F; font-weight: normal; font-style: normal;} -
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-
# Interface for unknown handlers:
-# nsf::object::unknown::add /key/ /handler/
-# nsf::object::unknown::get /key/
-# nsf::object::unknown::delete /key/
-# nsf::object::unknown::keys
+
# Interface for unknown handlers:
+# nsf::object::unknown::add /key/ /handler/
+# nsf::object::unknown::get /key/
+# nsf::object::unknown::delete /key/
+# nsf::object::unknown::keys
References