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Date: Mon, 3 Jun 2019 19:22:15 +0300
From: Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: [PATCH v1 6/8] box: export _func functions with box.func folder
Message-ID: <20190603162215.n2vecnpnnz7ucbi7@esperanza>
References: <cover.1559212747.git.kshcherbatov@tarantool.org>
 <928eff71554a492f736b8c7595f2a060f70364e5.1559212747.git.kshcherbatov@tarantool.org>
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In-Reply-To: <928eff71554a492f736b8c7595f2a060f70364e5.1559212747.git.kshcherbatov@tarantool.org>
To: Kirill Shcherbatov <kshcherbatov@tarantool.org>
Cc: tarantool-patches@freelists.org
List-ID: <tarantool-patches.dev.tarantool.org>

On Thu, May 30, 2019 at 01:45:33PM +0300, Kirill Shcherbatov wrote:
> Closes #4182
> Needed for #1260
> 
> @TarantoolBot document
> Title: Persistent Lua functions
> 
> Lua functions managed by Tarantool are called 'persistent'.
> They are stored in snapshoot and are available after server
> restart.
> Persistent Lua functions are exported in box.schema.func.persistent
> folder. They may be called via .call exported object method or
> via netbox:call.
> 
> Some restrictions must be accounted writing such routines:
> 1. only limited set of Lua functions and modules are available:
> -assert -error -pairs -ipairs -next -pcall -xpcall -type
> -print -select -string -tonumber -tostring -unpack -math -utf8;
> 2. global variables are forbidden.
> 
> Moreover all functions and their metadata are now exported in
> box.func table (not only persistent). Persistent Lua functions
> have box.func.FUNCNAME.call() method to execute it in interactive
> console.
> Persistent Lua functions are also available with net.box call.
> 
> Example:
> lua_code = [[function(a, b) return a + b end]]
> box.schema.func.create('sum', {
>                        body = lua_code, is_deterministic = true,
>                        returns = 'integer', is_deterministic = true})
> box.func.sum
> - call: 'function: 0x4016b6a0'
>   returns: integer
>   is_deterministic: true
>   id: 2
>   language: LUA
>   name: sum
>   is_persistent: true
>   setuid: false
> 
> box.func.sum.call(1, 2)

I think 'call' should work for all kinds of functions, not only
persistent. That is, this should probably be the first patch in
the series.

Also, I'd expect 'call' to be a method of the function class:

  box.func.sum:call(1, 2)