patch 9.0.1001: classes are not documented or implemented yet
Problem: Classes are not documented or implemented yet.
Solution: Make the first steps at documenting Vim9 objects, classes and
interfaces. Make initial choices for the syntax. Add a skeleton
implementation. Add "public" and "this" in the command table.
diff --git a/runtime/doc/vim9.txt b/runtime/doc/vim9.txt
index d7f7808..1b1298c 100644
--- a/runtime/doc/vim9.txt
+++ b/runtime/doc/vim9.txt
@@ -16,7 +16,7 @@
3. New style functions |fast-functions|
4. Types |vim9-types|
5. Namespace, Import and Export |vim9script|
-6. Future work: classes |vim9-classes|
+6. Classes and interfaces |vim9-classes|
9. Rationale |vim9-rationale|
@@ -1940,73 +1940,17 @@
==============================================================================
-6. Future work: classes *vim9-classes*
+6. Classes and interfaces *vim9-classes*
-Above "class" was mentioned a few times, but it has not been implemented yet.
-Most of Vim9 script can be created without this functionality, and since
-implementing classes is going to be a lot of work, it is left for the future.
-For now we'll just make sure classes can be added later.
+In legacy script a Dictionary could be used as a kind-of object, by adding
+members that are functions. However, this is quite inefficient and requires
+the writer to do the work of making sure all the objects have the right
+members. See |Dictionary-function|.
-Thoughts:
-- `class` / `endclass`, the whole class must be in one file
-- Class names are always CamelCase (to avoid a name clash with builtin types)
-- A single constructor called "constructor" (similar to TypeScript)
-- Single inheritance: `class ThisClass extends BaseClass`
-- `interface` / `endinterface` (looks like a class without any implementation)
-- Explicit declaration that the class supports an interface, so that type
- checking works properly:
- `class SomeClass implements SomeInterface, OtherInterface`
-- `abstract class` (class with incomplete implementation) - not really needed?
-- Class (static) methods and Object methods: syntax to be defined.
-- Class (static) members and Object members: syntax to be defined.
-- Access control: private / protected / shared / public ? Keep it simple.
-- Access object members with `this.member` ?
-- Generics for class: `class <Tkey, Tentry>`
-- Generics for function: `def <Tkey> GetLast(key: Tkey)`
-- Method overloading (two methods with the same name but different argument
- types): Most likely not
-- Mixins: not sure if that is useful, leave out for simplicity.
+In |Vim9| script you can have classes, objects and interfaces like in most
+popular object-oriented programming languages. Since this is a lot of
+functionality it is located in a separate help file: |vim9class.txt|.
-Again, much of this is from TypeScript with a slightly different syntax.
-
-Some things that look like good additions:
-- Use a class as an interface (like Dart)
-- Extend a class with methods, using an import (like Dart)
-- Mixins
-- For testing: Mock mechanism
-
-An important class that will be provided is "Promise". Since Vim is single
-threaded, connecting asynchronous operations is a natural way of allowing
-plugins to do their work without blocking the user. It's a uniform way to
-invoke callbacks and handle timeouts and errors.
-
-Some commands have already been reserved:
- *:class*
- *:endclass*
- *:abstract*
- *:enum*
- *:endenum*
- *:interface*
- *:endinterface*
- *:static*
- *:type*
-
-Some examples: >
-
- abstract class Person
- static const prefix = 'xxx'
- var name: string
-
- def constructor(name: string)
- this.name = name
- enddef
-
- def display(): void
- echo name
- enddef
-
- abstract def find(string): Person
- endclass
==============================================================================
@@ -2293,18 +2237,5 @@
support for classes in Vim is then a problem.
-Classes ~
-
-Vim supports a kind-of object oriented programming by adding methods to a
-dictionary. With some care this can be made to work, but it does not look
-like real classes. On top of that, it's quite slow, because of the use of
-dictionaries.
-
-It would be good to support real classes, and this is planned for a later
-version. The support is a "minimal common functionality" of class support in
-most languages. It will work much like Java, which is the most popular
-programming language.
-
-
vim:tw=78:ts=8:noet:ft=help:norl: