How do I convert my pinescript v2 to pinescript v4?

Question

I have a pinescript v2 that needs to be converted to v4, but I still haven't understood how, any inputs will be useful, thanks. This script was developed a long time back and visiting it now is confusing me. I have been reading that the variables need to be declared first, I get that, but what is the most efficient way to convert this into v4 of pine?

//@version=2
study(title="SuperTrend Oscillator",shorttitle="STO",overlay=false)
//Inputs
spt_ures=input(false,title="Use Cutsom Resolution?")
spt_res=input(type=resolution,defval="M")
spt_lenw=input(200,title="Length Of Warning Range")
spt_len=input(14,title="SuperTrend Length")
spt_mult=input(1,title="SuperTrend Multiple")
spt_ubc=input(true,title="Use Barcolors?")
colup=green
coldn=red
//SuperTrend
spt_atr=atr(spt_len)
spt_nsb=hl2+spt_atr*spt_mult
spt_nlb=hl2-spt_atr*spt_mult
spt_lb=close[1]>spt_lb[1]?max(spt_nlb,spt_lb[1]):spt_nlb
spt_sb=close[1]<spt_sb[1]?min(spt_nsb,spt_sb[1]):spt_nsb
spt_tdur=close>spt_sb[1]?1:close<spt_lb[1]?-1:nz(spt_tdur[1],1)
spt_td=spt_ures?(security(tickerid,spt_res,spt_tdur)):spt_tdur
spt_lvlur=(close-(spt_td==1?spt_lb:spt_sb))
spt_lvl=spt_ures?(security(tickerid,spt_res,spt_lvlur)):spt_lvlur
//Components
spt_lvlup=spt_td==1?spt_lvl:na
spt_lvldn=spt_td==-1?spt_lvl:na
spt_tdup=(spt_td==1)and(spt_td[1]==-1)
spt_tddn=(spt_td==-1)and(spt_td[1]==1)
spt_tr=spt_ures?(security(tickerid,spt_res,tr)):tr
spt_matr=sma(abs(spt_lvl),200)
spt_cls=spt_ures?(security(tickerid,spt_res,close)):close
spt_lvlwup=(spt_lvlup<spt_matr)and(spt_cls<spt_cls[1])
spt_lvlwdn=(spt_lvldn>-spt_matr)and(spt_cls>spt_cls[1])
//Color
spt_col=spt_td==1?colup:coldn
spt_colbar=(spt_td==1)and(spt_lvlwup)?#A7D1AA:(spt_td==-1)and(spt_lvlwdn)?#D1A7AE:spt_td==1?colup:coldn
spt_colhst=spt_tdup?colup:spt_tddn?coldn:spt_lvlwdn?colup:spt_lvlwup?coldn:na
//Plot
p0=plot(0,color=spt_col,style=line,linewidth=1,transp=0,title="Midline")
p1=plot(spt_lvlup,color=colup,style=linebr,linewidth=1,transp=0,title="Uptrend Line")
p2=plot(spt_lvldn,color=coldn,style=linebr,linewidth=1,transp=0,title="Downtrend Line")
plot(spt_lvl,color=spt_colhst,style=histogram,linewidth=3,transp=0,title="Trend Change")
plot(spt_lvl,color=spt_colhst,style=circles,linewidth=2,transp=0,title="Trend Change")
fill(p0,p1,color=colup,transp=90)
fill(p0,p2,color=red,transp=90)
barcolor(spt_ubc?spt_colbar:na)

Answer 1

Take a look at the v2 to v3 migration guide first, once your script is v3 compatible you can often juste use the v4, you can also use the "convert to v4" option.

Answer 2

You're in luck because Pine v4 now has a supertrend() built-in .

You will also want to look into How to avoid repainting when using security() - PineCoders FAQ to avoid the lookahead bias that v2 is suffering from.

That should give you a head start. If you get stuck along the way and you can post your code, let us know.