Why do I keep getting ‘undeclared identifier’ error message on pine script?

I’ve been getting undeclared identifier’ error message on pine script and now it’s getting frustrating.

line 19 : Undeclared identifier 'lag_s_k';
line 19 : Undeclared identifier 's1';
line 19 : Undeclared identifier  's3';
line 22 : Undeclared identifier 'vol';
line 24 : Undeclared identifier 'vol';
line 26 : Undeclared identifier 'vol_m'

This is the full code, Thanks y’all.

dummydv = input(false, title="Damiani Volatmeter")
usevolmode = true 
//input(true, title = "use 
volume Mode")
vis_atr = input(13)
vis_std = input(20)
sed_atr = input(40)
sed_std = input(100)
threshold_level = input(1.4)
lag_supressor = input(true)
atrv(len)=>rma(volume,len)
//DV(13,20,40,100,1.4,true) 
  DV(vis_atr,vis_std,sed_atr,sed_std, threshold_level,lag_supressor)=>
 vol = 0.0
 lag_s_K = 0.5
 s1=nz(vol[1], 0)
 s3=nz(vol[3], 0)

vol = lag_supressor ? atr(vis_atr) / atr(sed_atr) + lag_s_K*(s1-s3) : atr(vis_atr) / atr(sed_atr)
anti_thres = stdev(close, vis_std) / stdev(close, sed_std)
t = threshold_level - anti_thres
vol_m = vol > t ? -1 : 0.03

plot (title="V",  series=vol, color=color.lime)
plot(title="A", series=t, color=color.silver)
plot(title="T", series=vol_m, color=color.maroon)

Answer

Variables that are declared inside a function can only be used inside that function. It is also important to observe the correct number of spaces.

dummydv = input(false, title="Damiani Volatmeter")
usevolmode = true 
//input(true, title = "use volume Mode")
vis_atr = input(13)
vis_std = input(20)
sed_atr = input(40)
sed_std = input(100)
threshold_level = input(1.4)
lag_supressor = input(true)
atrv(len)=>rma(volume,len)
//DV(13,20,40,100,1.4,true) 
//DV(vis_atr,vis_std,sed_atr,sed_std, threshold_level,lag_supressor)=>
vol = 0.0
lag_s_K = 0.5
s1=nz(vol[1], 0)
s3=nz(vol[3], 0)

vol := lag_supressor ? atr(vis_atr) / atr(sed_atr) + lag_s_K*(s1-s3) : atr(vis_atr) / atr(sed_atr)
anti_thres = stdev(close, vis_std) / stdev(close, sed_std)
t = threshold_level - anti_thres
vol_m = vol > t ? -1 : 0.03

plot (title="V",  series=vol, color=color.lime)
plot(title="A", series=t, color=color.silver)
plot(title="T", series=vol_m, color=color.maroon)