Interpolation

Sometimes, construction on Expression objects is difficult, especially when you have multiple objects and/or variables. This is used for easy and readable expression construction.

So, interpolation is a way to deal with this. Such objects can be interpolated into the expression construction through a $ prefix. This process is also called splicing expressions, variables, or literals into quoted expressions.

How to do it...

Suppose there is a literal p, which has to be interpolated for constructing an expression with other literals; this is how it would be done:

p = 6;
exp = :(20 + $p)

This is how it would look:

For nested quoting, each symbol must be quoted separately, along with splicing the overall parentheses of the nested expression:

p = 6;
q = 7;
:(:p in $(  :(:p * :q ) ) )

This is how it would look in the REPL:

Even data structures can be spliced into an expression construction. Now, let's consider the tuple data structure for splicing into an expression builder...