read-only account (Rain 🚱)in Lua:
`(function()end)() == nil` is true but
`(function()end)()` and `(function() return nil end)()` print different things at the REPL
lizard appreciator@grainloom huh, in ruby a void function just returns nil:
def nnn
nil
end
# => :nnn
def voidvoid
#noop
end
# => :voidvoid
nnn # => nil
voidvoid # => nil
nnn == voidvoid # => true
@bonzoesc yuh, in Lua there is actually a stack for the return values or something
in Python, you can return multiple things but it's actually just syntax sugar for returning a tuple, whereas in Lua you are pushing things onto a stack
eg. you can do
local a, nil1, nil2 = (function()return 1 end)()
-- a == 1 and nil1 == nil and nil2 == nil
@bonzoesc and you can also ignore a few returned values, this is often used instead of result types:
loadstring("bad source code")
will return nil and an error message
loadstring("return 1")
will return a funtion
if you don't expect an error then you get nil and trying to use that will sooner or later blow up
@bonzoesc
the proper way to handle that would be
local f = assert(loadstring(source_code))
if given a false-y value, assert will call error with its second parameter
@grainloom yeah, ruby does the destructuring assignment like that (but with Arrays since no tuples)
not sure how i feel about it all, kinda neat that all these languages found different things to work for different people
clacke: exhausted pixie dream boy 🇸🇪🇭🇰💙💛@grainloom In Lua 5 and LuaJit 2 both seem to print nothing at the REPL.
@clacke
LuaJIT 2.0.5 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
JIT: ON CMOV SSE2 SSE3 SSE4.1 fold cse dce fwd dse narrow loop abc sink fuse
> =(function()end)()
> =(function() return nil end)()
nil
>
LuaJIT 2.0.5 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
JIT: ON CMOV SSE2 SSE3 SSE4.1 fold cse dce fwd dse narrow loop abc sink fuse
> =(function()end)()
> =(function() return nil end)()
nil
>