Comment by evdubs

Embedded in this response is a consideration for how programming languages handle data. In Java, if you have a config file, does that file use Java syntax? No. What is that Java file written in? Likely XML. Can you write XML literals in Java? No. Wouldn't it be nice to:

    XMLElement el = <html><body>Hello World!</body></html>;

In JavaScript, we have probably the closest to Lisp in this regard with JSON. You can define JSON literals in your JavaScript code; config files like package.json are written using this object notation. If you want to work with, say XML, there are libraries to convert your XML to JSON and you can take it from there.

But, JSON is limited. How do you define dates for your datatypes? Probably use a string. In Lisp, you can use a string or have some (date year month day) form. How do you represent rational numbers? Maybe you'll risk using floating point or you'll just go with a string. Lisps have rationals built in or you could roll your own with (rational numerator denominator). So your JSON

    {
      'name': 'John Doe',
      'birth-date': '1970-01-01',
      'account-balance': '1000.01'
    }

can become

    (user #:name "John Doe" #:birth-date (date 1970 1 1) #:account-balance 100001/100)

When Lispers need to interact with JSON, they convert it to S-expressions. When Lispers need to interact with XML, they convert it to S-expressions. Wouldn't it be nice if the other languages had syntaxes that made you want to define data using that language's syntax and not JSON or XML?