Hi all,

First time poster and overall Lua and Pico-8 noob. I have played several of the games and watched a few videos on making games and now I'm playing around with creating basic functionality. However, I'm getting stuck with a syntax error that doesn't make any sense to me. Here is my source code:

room={}
room.x1=0   --x1 coordinate (coord)
room.y1=0   --y1 coord
room.x2=127 --x2 coord
room.y2=127 --y2 coord
room.w=119  --room width
room.h=119  --room height

p={}        --person object
p.x=63      --start x coord
p.y=63          --start y coord
p.sprite=0      --start sprite

function _init()

end

function _update()
    update_movement()
end

function update_movement()
    if btn(0) and not_border() then
            move_left()
    end
    if btn(1) and not_border() then
        move_right()
    end
    if btn(2) and not_border() then
        move_up()
    end
    if btn(3) and not_border() then
        move_down()
    end
end

function not_border()
    (p.x>1 and p.x<119) or (p.y>1 and p.y<119)
end

function move_left()
    p.x-=1
end

function move_right()
    p.x+=1
end

function move_up()
    p.y-=1
end

function move_down()
    p.y+=1
end

function _draw()
    cls()
    -- draw room boarder
    rect(room.x1,
        room.y1,
        room.x2,
        room.y2,
        10)
    -- draw sprite
    spr(0,p.x,p.y)
end

The problem I am having is with my not_border() function. It says there is a <EOF> syntax error near 'or', but looking at my code it appears that I have my and and or statements written out correctly. Can someone help me understand what is wrong with this specific function and why I am getting the syntax error I'm getting? Thanks!

Since you want not_border() to return a True or False, you want to do this instead:

function not_border()
    return (p.x>1 and p.x<119) or (p.y>1 and p.y<119)
end

I believe not_border() wants to return a value?

Does it work better like this?

function not_border()
    return ( (p.x>1 and p.x<119) or (p.y>1 and p.y<119) )
end

Edit : Yeah, what he said.

Bah,

Thank you. I grew up on Ruby, which doesn't require explicit returns. I saw that Lua was a scripting language and immediately assumed that it functioned with implicit returns. Now I know. Many thanks!

I've never ruby'ed. A non-assigning statement at the end implies the return value?

That's either neat or really messed up. I can't decide. :)

Sort of correct. In Ruby, whatever the final statement evaluated in a function is, that is the return value, even if it is an assigning statement. For example:

def my_foobar_method do
  my_var = "Hello World"
end

def my_other_foobar_method do
  "Hello World"
end

Both would return the string "Hello World". Some hate it. Some love it. I don't know that I either love or hate it. It is just what I started with and so it often becomes my default mindset when programming.

Hm, interesting. As most programmers end up doing, I fiddled with designing my own language. I made it so that what is effectively my function's 'end' statement (which is actually a loc/lang-independent symbol in my case) doubles as the return keyword. Similar. So I kind of approve. :)