You can imagine that a quote is something like a tag that you may attach to data. It is a feature that opens the doors to many possibilities. You can use them with user data structures, in message passing, data driven programming and metaprogramming that we will see later.
For now, let's just introduce the topic.
(quote this-is-a-quote)-> this-is-a-quote
The above expression creates the quote symbol this-is-a-quote.
Traditionally in LISP dialects, there is an alternative way to create quotes,
using the single quote character '. It is often preferred for its convenience.
Generally, 'abc is equivalent to (quote abc).
'this-is-a-quote-> this-is-a-quote
A quote symbol is unique during an evaluation session, so it comes in handy for equality checks. For example, we can check if something is tagged with a particular text.
The comparisons are also performant, because quotes are reference types, which means that only memory addresses are compared.
(= 'this-is-a-quote 'this-is-a-quote)-> true
Also, they are case sensitive.
(= 'this-is-a-quote 'This-is-a-quote)-> false
You can also create lists of quotes.
'(ab cd 10 20 30)-> (ab cd 10 20 30)
or equivalently
(quote (ab cd 10 20 30))-> (ab cd 10 20 30)
Something notable is that a quote of a primitive literal in RainLisp is just a quote. For example
'10is the quote symbol10and cannot be handled like a number. Whereas in other LISP dialects, it can. You can add it or do anything to it that you can to numbers. In RainLisp, once a quote, always a quote.
If you want to see more examples, look at the specification.
Congratulations! You have covered all the basics of RainLisp. It's time to move on to data structures.