love2d thinks the number "3" is a bool

[fixylol]

i have a function that calculates the position of an enemy in tiles (32x32 squares). i have the starting position of the enemies stored in a table. for some reason, when love.graphics.draw tries to draw the enemy onto the screen, it thinks the first value of the table (which by the way is 3) is a bool value, and i cant figure out why. there isnt a single bool value within the entire level.

here's a love file in case you don't understand: (press P to advance to the next level)

awedd-beta.love

(6.1 MiB) Downloaded 262 times

Edit: nevermind, i was dumb

[DaedalusYoung]

This:

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v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1

seems to return false.

[fixylol]

This:

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v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1

seems to return false.

it'shouldnt set the value to false though :/

[TheOdyssey]

That does generates a boolean

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 v[2] = v[3] == 2 

Is the exact same thing as

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if v[3] == 2 then
     v[2] = true
end

[zorg]

Probably some precedence issues;

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-- v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1 should be
something = ((v[3] == 2) and (v[2] + 1)) or ((v[3] == 4) and (v[2] - 1))

...well, technically, you could only enclose the whole clause after the or, but this is a bit more straightforward.

[airstruck]

Adding those parens won't change precedence; "==" > "and" > "or" (see PIL 3.5) so "A == B and C or D == E and F" is equivalent to "((A == B) and C) or ((D == E) and F)" ... if A ~= B and D ~= E then the expression does evaluate to false, though (noted earlier).

[vrld]

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x = v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1

is equivalent to:

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if v[3] == 2 then
    x = v[2] + 1
elseif v[3] == 4 then
    x = v[2] - 1
else
    x = false
end

Are you sure v[3] is always 2 or 4?

[DPlayer234]

The solution is pretty simple.
This: (lines 225-228)

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for i,v in pairs(CurrentLevel.Enemies) do
    v[1] = v[3] == 1 and v[1] + 1 or v[3] == 3 and v[1] - 1
    v[2] = v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1
end

would set v[1] to false if neither "v[3] == 1" or "v[3] == 3" return true. (Same for v[2])

Why? In case no statement in such a "chain" is true, it will return false.

What I did to prevent the crash was simple:

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for i,v in pairs(CurrentLevel.Enemies) do
    v[1] = v[3] == 1 and v[1] + 1 or v[3] == 3 and v[1] - 1 or 1
    v[2] = v[3] == 2 and v[2] + 1 or v[3] == 4 and v[2] - 1 or 1
end

This code will now make it return 1 if both "v[3] == 1" and "v[3] == 3" return true (the "or 1"-part does that).

[zorg]

This code will now make it return 1 if both "v[3] == 1" and "v[3] == 3" return true (the "or 1"-part does that).

You mean it'll return 1 if both return false; if both returned true, then it'd set the value to the first in the chain.

[DPlayer234]

This code will now make it return 1 if both "v[3] == 1" and "v[3] == 3" return true (the "or 1"-part does that).

You mean it'll return 1 if both return false; if both returned true, then it'd set the value to the first in the chain.

Oh yeah, right. Of course. My bad.