Is there a way to catch the output in lua?

Question

I'm trying to catch the output from for example: print('Hello') and store it in a variable / table.

Please let me know if this is even possible. If not thanks for answering.

I can't tell what you're trying to do. You seem to be asking for a way to intercept output, but [`load`](https://www.lua.org/manual/5.3/manual.html#pdf-load) is unrelated to output. In your example, `print` returns nothing, but `load` requires a string or function argument. — luther, Mar 01 '20 at 18:05
I'm trying to catch the output from for example print('Hello') and store it in a variable/table, sorry for bad explanation. — TritriGuy123, Mar 01 '20 at 18:08

luther · Accepted Answer · 2020-03-01T20:06:33.057

0

You can't intercept standard output directly, but you can change the global print function:

local outputs = {}
local function storeOutputs(...)
  table.insert(outputs, {...})
end

local oldPrint = print
function print(...)
  storeOutputs(...)
  oldPrint(...)
end

I'm not sure if there's a way to deal with io.write calls.

edited Mar 01 '20 at 20:06

answered Mar 01 '20 at 18:50

luther

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Assigning to `io.stdout` does not affect `io.write()` behavior. Lua does not use `io.stdout` (situation very similar to `_G`) – Egor Skriptunoff Mar 01 '20 at 19:15
Thanks for answering so quick, and with exacly what I wanted! – TritriGuy123 Mar 01 '20 at 19:37
@EgorSkriptunoff: Bummer. I'll have to delete that part of my answer for now. There might be a more complicated way to do it, like rewriting all of the output-related `io` functions. – luther Mar 01 '20 at 20:04
@luther - See `io.output()` – Egor Skriptunoff Mar 01 '20 at 21:00

Is there a way to catch the output in lua?

1 Answers1