Pine Script language syntax

I just start to learning Pine Script. And I cant find any information about this issue in language documentation or google. This code is working and I find it in someones indicator script.

I want to understand what this means:

1. if (float)

float = float ? float : float
    
float ph = ta.pivothigh(prd, prd)
float pl = ta.pivotlow(prd, prd)
    
float lastpp = ph ? ph : pl ? pl : na
    
if lastpp
    ...

?: is called ternary operator.

The way it works is, it will check a condition and return value1 if the condition is true and return value2 otherwise.

condition ? value1: value2

You can write the same check with an if block as below:

if (condition)
    value1
else
    value2

Edit:

ta.pivothigh will return NaN if there is no pivot. NaN is not a number so when you run it in a condition it will return false.

Essentially, what ph ? checks is to see if there is a pivot high or not.