runtime(doc): Update the 'specifies' keyword documentation, slightly reformat
closes: #16648
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/vim9class.txt b/runtime/doc/vim9class.txt
index 5e5c28e..7ba91e7 100644
--- a/runtime/doc/vim9class.txt
+++ b/runtime/doc/vim9class.txt
@@ -1,4 +1,4 @@
-*vim9class.txt* For Vim version 9.1. Last change: 2025 Feb 11
+*vim9class.txt* For Vim version 9.1. Last change: 2025 Feb 16
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -52,7 +52,6 @@
The class hierarchy allows for single inheritance. Otherwise interfaces are
to be used where needed.
-
Class modeling ~
You can model classes any way you like. Keep in mind what you are building,
@@ -122,7 +121,6 @@
A class name cannot be used as an expression. A class name cannot be used in
the left-hand-side of an assignment.
-
Object variable write access ~
*read-only-variable*
Now try to change an object variable directly: >
@@ -626,13 +624,15 @@
extends ClassName
implements InterfaceName, OtherInterface
specifies SomeInterface
-< *E1355* *E1369*
+<
+The "specifies" feature is currently not implemented.
+
+ *E1355* *E1369*
Each variable and method name can be used only once. It is not possible to
define a method with the same name and different type of arguments. It is not
possible to use a public and protected member variable with the same name. An
object variable name used in a super class cannot be reused in a child class.
-
Object Variable Initialization ~
If the type of a variable is not explicitly specified in a class, then it is
@@ -689,13 +689,12 @@
only appear once *E1350* . Multiple interfaces can be specified, separated by
commas. Each interface name can appear only once. *E1351*
-
A class defining an interface ~
*specifies*
A class can declare its interface, the object variables and methods, with a
named interface. This avoids the need for separately specifying the
interface, which is often done in many languages, especially Java.
-
+TODO: This is currently not implemented.
Items in a class ~
*E1318* *E1325* *E1388*
@@ -736,25 +735,25 @@
used with an object. An object can implement a method with the same name as
these builtin functions to return an object-specific value.
- *E1412*
+ *E1412*
The following builtin methods are supported:
- *object-empty()*
+ *object-empty()*
empty() Invoked by the |empty()| function to check whether an object is
empty. If this method is missing, then true is returned. This
method should not accept any arguments and must return a boolean.
- *object-len()*
+ *object-len()*
len() Invoked by the |len()| function to return the length of an
object. If this method is missing in the class, then an error is
given and zero is returned. This method should not accept any
arguments and must return a number.
- *object-string()*
+ *object-string()*
string() Invoked by the |string()| function to get a textual
representation of an object. Also used by the |:echo| command
for an object. If this method is missing in the class, then a
built-in default textual representation is used. This method
should not accept any arguments and must return a string.
- *E1413*
+ *E1413*
A class method cannot be used as a builtin method.
Defining an interface ~
@@ -786,7 +785,6 @@
An interface cannot "implement" another interface but it can "extend" another
interface. *E1381*
-
null object ~
When a variable is declared to have the type of an object, but it is not
@@ -795,7 +793,6 @@
a variable name is correct and you will get a "Using a null object" error,
even when the variable name is invalid. *E1360* *E1362*
-
Default constructor ~
*default-constructor*
In case you define a class without a new() method, one will be automatically
@@ -1118,7 +1115,6 @@
the right choice, and by calling it new() the relation between the caller and
the method being called is obvious.
-
No overloading of the constructor ~
In Vim script, both legacy and |Vim9| script, there is no overloading of
@@ -1139,7 +1135,6 @@
is very easy to see which constructor is being used. And the type of
arguments can be properly checked.
-
No overloading of methods ~
Same reasoning as for the constructor: It is often not obvious what type
@@ -1148,7 +1143,6 @@
type checking will make sure it works as you intended. This rules out
polymorphism, which we don't really need anyway.
-
Single inheritance and interfaces ~
Some languages support multiple inheritance. Although that can be useful in
@@ -1164,7 +1158,6 @@
class implements an interface just because the methods happen to match is
brittle and leads to obscure problems, let's not do that.
-
Using "this.variable" everywhere ~
The object variables in various programming languages can often be accessed in
@@ -1183,7 +1176,6 @@
it's also directly clear which variable references are object variables and
which aren't.
-
Using class variables ~
Using "static variable" to declare a class variable is very common, nothing
@@ -1197,7 +1189,6 @@
up quite a bit of space, and when the class is renamed all these places need
to be changed too.
-
Declaring object and class variables ~
The main choice is whether to use "var" as with variable declarations.
@@ -1251,7 +1242,6 @@
reuses the general function declaration syntax for methods. So, for the sake
of consistency, we require "var" in these declarations.
-
Using "ClassName.new()" to construct an object ~
Many languages use the "new" operator to create an object, which is actually
@@ -1315,7 +1305,6 @@
"public" changes the access in the other direction. Well, that's just to
reduce the number of keywords.
-
No private object variables ~
Some languages provide several ways to control access to object variables.