[Tarantool-patches] [PATCH v4 0/6] box/func: implement cfunc Lua module

[Cyrill Gorcunov]

On Sat, Oct 03, 2020 at 03:55:23PM +0200, Vladislav Shpilevoy wrote:
> Hi! Thanks for the patchset!
> 
> On 01.10.2020 15:51, Cyrill Gorcunov wrote:
> > The cfunc module provide a way to execute C stored procedures
> > on read only nodes without registring them in `_func` system space.
> > 
> > The series implements a bare minimum. There was a request to make
> > cfunc been Lua object with appropriate methods. If this is really
> > preferred then I'll implement this wrapping Lua code on top. I mean
> > that currently all operations are done via
> > 
> >  > require('cfunc').[create|drop|call|reload]
> > 
> > interface while there was a proposal to operate as
> > 
> >  > a = require('cfunc').create
> >  > a:call(args)
> 
> No, the proposal was rather
> 
> 	cfunc = require('cfunc')
> 	f = cfunc.load('test_box_c_function')
> 	f(1, 2, 3)
> 
> Sorry I didn't describe it properly anywhere. But it is easy to fix
> anyway.
> 
> In Lua you can define __call and make an object look exactly
> like a function. That is the idea behind making it possible to
> use Lua and C functions in the same way.
> 
> 	if load_c then
> 		f = cfunc.load('test_box_c_function')
> 	else
> 		f = function(a, b, c) return a + b + c end
> 	end
> 	f(1, 2, 3) -- Works and looks the same for C and Lua.
> 
> With this way even IPROTO_CALL should work on such functions, if the
> function object is global and the user has access to executing everything
> here.

OK, so here is a proposal. The module get called cbox, where we will be
implementing all C related features.

cbox.func.create(name)		-- create a function
cbox.func.drop(name)		-- delete a function
cbox.module.reload(name)	-- reload module

f = cbox.func.create(name)
f(1,2,3)			-- create and call a function

Comments?