While discussing language design, a predicate is an expression that evaluates to a boolean.
The purpose of the predicate is to allow branching within the code.
There are multiple ways to define how you would like to identify the predicate structure. One of the most common is the utilization of the if command
i.e.
if predicate
command-block
additionally
if predicate
command-block
else
command-block
You can also define predicate structure in far more interesting designs
expression if predicate
predicate do command-block
Predicates are also used for conditional looping;
such as whiles
while predicate
command-block
while predicate
command-block
then
command-block
or Do structures
do
command-block
while predicate
