Re: Sharing locals with a function created using "load"

[Philipp Janda <siffiejoe@...>]

Am 04.05.2015 um 04:16 schröbte Ignacio Burgueño:
> Hi.

Hi!

> I'm writing some code where I need to generate functions based on a string
> template.
>
> For instance, in the following template:
> [[
> function (cpu)
>    logger.debug("RLC %s")
>    cpu.%s = RLC(cpu, cpu.%s)
>    cpu.PC = (cpu.PC + 2) & 0xffff
> end
> ]]
>
> "logger" and "RLC" are locals. I'm loading that template with load and when
> running the resulting function, it complains about "logger" being nil.
>
> I could provide a table with those variables, but I have many besides those
> three, and they depend on the given template. Also, I'd like to avoid those
> variables being resolved as globals.
>
> Is there any way I could "inject" locals into the function?
>
> I thought about changing the template to:
> [[
> local logger, RLC
> function (cpu)
>    logger.debug("RLC %s")
>    cpu.%s = RLC(cpu, cpu.%s)
>    cpu.PC = (cpu.PC + 2) & 0xffff
> end
> ]]
> and then using debug.getupvalue / setupvalue to bind those locals. This
> seems to be feasible, but I'd like to know if there is an easier way.

I usually use something like

    local s = [[
    local logger, RLC = ...
    return function (cpu)
      -- some code
    end
    ]]

    local f = assert(load(s, s, "t", {}))(logger, RLC)

for this.

> Regards,
> Ignacio

Philipp