7 replies to this topic

[ChaosNicro]

Hello there,

I am trying to write a program that is supposed to take boolean type values as arguments.
When all the statements relating to these boolean values were considered true regardless of the input, I discovered that they had been picked up as strings instead.
I then solved this by using this construct:

if arg[2] == "false" then
   local direction = false
else
   local direction = true
end

I know it's considered a strength that Lua automatically assigns types to variables but is there a way to force a certain type?
Maybe I am better of using a different input and comparing to the strings.

Thanks in advance

[Creator]

Only strings.

Your solution does the job, so don't worry about it.

[Lupus590]

a better solution would be

local direction --# otherwise this is local to the if statement
if arg[2] == "true" then
  direction = true
elseif arg[2] == "false" then
  direction = false
else
  --#insert some way to handle a bad argument
end

Edited by Lupus590, 17 April 2016 - 09:20 PM.

[MKlegoman357]

ChaosNicro, on 17 April 2016 - 08:30 PM, said:

I know it's considered a strength that Lua automatically assigns types to variables...

It's the shell program that parses the arguments and gives you a string, not Lua. There's no such thing as 'automatically assign a type to a variable'. Just wanted to put away this misconception you might have had

[Bomb Bloke]

Well, there's no static typing, at least.

Anyway, another way of writing it:

local direction = arg[2]:lower() == "true"

[ChaosNicro]

Alright, thanks everyone.
That problem solved!

[greygraphics]

You could also use

local direction = (args[2] == "true" and true) or (false)

[Lyqyd]

That's redundant, though. Bomb Bloke's answer is simple and results in the same values being returned, but accepts all capitalization combinations of "true" as true.