Why/How does this work?

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#1

Hey, and thanks for reading in advance. Stupid question warning!

I learned by reading a few scripts made by my friends that you can enumerate a true/false statement to a number without needing an if/then block.

local bool = false
local number = 7

number = number + ((bool and 3) or 0)

-- is the same as --

if bool then
number += 3
end

How exactly does that evaluate to a number? Are there any other weird syntax shortcuts like this?
Sorry, not exactly a high-priority thread, just curious.

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Stupid table won't work without any errors my god
#2

that is what you’d call an addition assign operator. The addition assignment operator ( += ) adds the value of the right operand to a variable and assigns the result to the variable. The types of the two operands determine the behavior of the addition assignment operator. Addition or concatenation is possible.

#3

no im pretty sure its just luas version of ternary operators
http://lua-users.org/wiki/TernaryOperator
“x = a and b or c”

#4

This basically means:

local number = 7 -- number

if bool then -- ((bool
    number += 3 -- and 3)
else
    number += 0 -- or 0)
end

and in this case is the same as do or if, and or in this case is an else.

In words:

--number = number + ((        bool and 3        )                  or 0                 )
--number = number + ((if bool is true then add 3)     else if bool isn't true then add 0)

+= is just syntax sugar for variable = variable +:

number += 1

--// is the same as

number = number + 1
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#5

yes i was explaining the addition assignment operator as that was being used in the second comparison, but yes the ternary operator is also being used.

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