thinkScript Conditions: if, then, else statement

def pattern = if condition then 1 else 0;

declare lower;

def red_bar = close < open;
plot spike = if red_bar then 1 else 0;

#
# TD Ameritrade IP Company, Inc. (c) 2011-2020
#

input length = 20;
input trendSetup = 3;

def BodyMax = Max(open, close);
def BodyMin = Min(open, close);
def IsEngulfing = BodyMax > BodyMax[1] and
    BodyMin < BodyMin[1];
def IsWhite = open < close;
def IsBlack = open > close;
def IsPrevDoji = IsDoji(length)[1];

def Bearish = IsAscending(close, trendSetup)[1] and
    (IsWhite[1] or IsPrevDoji) and
    IsBlack and
    IsEngulfing;

def Bullish = IsDescending(close, trendSetup)[1] and
    (IsBlack[1] or IsPrevDoji) and
    IsWhite and
    IsEngulfing;

AssignPriceColor(if Bullish then color.green else if Bearish then color.red else color.white);