Re: Re-requiring modules

[Elias Barrionovo <elias.tandel@...>]

If you remove it's entry from package.loaded, and require it, it will
be loaded again.

But it's no so simple, because of possible side effects, locals,
upvalues and the like. Example:

local mod = require 'mymodule'
local foo = mod.foo
local mod = re_require 'mymodule'
print(foo == mod.foo)  -- what now?

On Tue, Oct 22, 2013 at 1:45 PM, Justin Cormack
<justin@specialbusservice.com> wrote:
>
> On 22 Oct 2013 16:38, "Robert Virding" <robert.virding@erlang-solutions.com>
> wrote:
>>
>> Is it possible to re-require a module? The documentation implies that it
>> is not possible as if the module has been loaded then it will be remembered
>> in the package.loaded table and the next time is it loaded then this value
>> will be reused.
>>
>> The scenario I was thinking about is a long-lived application where you
>> need to upgrade a module but don't want to take down the system as you will
>> have a lot state which needs to be maintained.
>>
>> It would also be interesting to speculate how to handle multiple versions
>> of a module in the same system. In one sense it would be easy if they were
>> kept in different places but overwriting an existing one may be tricky.
>>
>
> Sure, you can change package.loaded or just write your own require. The
> difficult bits are on the application side but all the tools are there.
>
> Justin



-- 
NI!

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