Hi all, I am very new to Lua programming - have been learning a bit of python and Gamemaker GML over the past year so still pretty fresh all round.

I have just finished coding the smoke particle but am getting the following error when trying to run it and I can't work out why:

SYNTAX ERROR LINE 10
<EOF>
')' EXPECTED NEAR '.4'

Here is my actual code:

function make_smoke(x,y,init_size,col)
					local s={}
					s.x=x
					s.y=y
					s.col=col
					s.width=init_size
					s.width_final=init_size+rnd(3)+1
					s.t=0 --how long lasts secs
					s.max_t=30+rnd(10) --how long lasts secs
					s.dx=(rnd(.8).4)
					s.dy=rnd(.05)
					s.ddy=.02 --simulate yaxis accel.
					add(smoke,s)
					return s
end
function _init()
					smoke={}
					cursorx=50
					cursory=50
					color=7
end

function move_smoke(sp)
if (sp.t>sp.max_t)then
					del(smoke,sp)
end
if(sp.t>sp.max_t15)then
				sp.width+=1
				sp.width=min(sp.width,sp.width_final)

end
sp.x=sp.x+sp.dx
sp.y=sp.y+sp.dy
sp.dy=sp.dy+sp.ddy
sp.t=sp.t+1
end
function _update()
foreach(smoke,move_smoke)
if btn(0,0)then cursorx=1 end
if btn(1,0)then cursorx+=1 end
if btn(2,0)then cursory-=1 end
if btn(3,0)then cursory+=1 end
if btn(4,0)then color=flr(rand(16))end
make_smoke(cursorx,cursory,rnd(4),color)
end				

function draw_smoke(s)
circfill(s.x,s.y,s.width,s.col)
end
function_draw()
cls()
foreach(smoke,draw_smoke)
end

Any ideas on what I have done wrong?

:) Mike

When I ran into this problem, I just put a * in front of the .4! I don't think parenthetical multiplication works when the parentheses are calling a function.

change
s.dx=(rnd(.8).4)
to
s.dx=(rnd(.8)*.4)

should do the trick

Thanks to both of you, that fixed that little problem now I have this:

SYNTAX ERROR LINE 53
<EOF>
<EOF> EXPECTED NEAR 'END'

Any idea what I haven't done right at end of code?

function_draw()

should be

function _draw()

note the space

(ignore my thoughts on foreach)

if btn(0,0)then cursorx=1 end

should be

if btn(0,0)then cursorx-=1 end

otherwise left cursor control doesn't work correctly

then just:

if (sp.t > sp.max_t15) then

should be

if (sp.t > sp.max_t+5) then

also see: https://www.lexaloffle.com/bbs/?tid=3260

Actually foreach() is a built-in function that takes a sequence and a function. It calls the function for each element in the sequence. It is not a loop and doesn't take a block (no do or end). It looks correct in the above code.

My apologies, I was thinking of for

Thanks so much - it worked with those revisions!

I believe the original intent was

if (sp.t > sp.max_t-15) then

because the article says "Then we grow the width of the particle if we are within 15 steps of the end of its life".

And it makes sense because smoke thickens as it departs from its origin.