pine-script v5, script error of Mismatched input 'var8' expecting 'end of line without line continuation'

Question

This is the logic of my script in words, "VAR8 assignment: If the lowest price <= VAR5, return (VAR4+VAR6*2)/2, otherwise return the 3-day exponential moving average of 0/618*VAR7"

and the following is the coverted script by ChatGPT3.5

// VAR5
var5 = ta.lowest(low, 30)

// VAR6
var6 = ta.highest(var4, 30)

// VAR7
var7 = if ta.sma(close,58) ? 1:0

// VAR8
var8 = low <= var5 ? (var4 + var6 * 2) / 2 : ta.ema(0, 3) / 618 * var7

Mismatched input 'var8' expecting 'end of line without line continuation'

I would like to know why there is such error occur and how to fix it?