Thursday, July 20, 2023

Re: [vim9script] On extending interfaces

> Also, if a concrete class has to implement both i1 and i2 explicitly,
> then i2 might as well not subclass i1.

Right, that's the approach I am currently adopting, which is fine
because my interfaces are small.

I may add that the problem with an orthogonal approach such as this:

interface I1
def Foo()
endinterface

interface I2
def Bar()
endinterface

class C implements I1, I2
...
endclass

class D implements I1, I2
...
endclass

is that there is no type for "C or D" or, more generally, for something
that "implements both I1 and I2", e.g.:

def F(X: ???)
X.Foo()
X.Bar()
enddef

where ??? = "anything implementing both I1 and I2". So, my current best
approximation is:

interface I1
def Foo()
endinterface

interface I2 # (Virtually) extends I1
def Foo()
def Bar()
endinterface

class C implements I1, I2
...
endclass

class D implements I1, I2
...
endclass

def F(X: I2)
X.Foo()
X.Bar()

def G(Y: I1)
Y.Foo()

which is perfectly fine (both F() and G() will accept objects of class
C or D), although the repetition in I2 may become a tad inconvenient if
I1 is large. Hence, my proposal.

Life.

--
--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php

---
You received this message because you are subscribed to the Google Groups "vim_use" group.
To unsubscribe from this group and stop receiving emails from it, send an email to vim_use+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/vim_use/u9b156%24bjn%241%40ciao.gmane.io.

No comments:

Post a Comment