If there is one Lisp function/macro/feature that you would like to see in a non-Lisp language, which one would it be?
This is another Friday social topic. You are aimlessly wandering around a beautiful hilltop by a sea when an angel approaches you from the opposite direction. She is no ordinary angel. She is a Lisp angel! She will grant one Lisp wish to you. Before she can fulfill your wish, she needs this information from you:
Your favorite Lisp dialect.
Your favorite non-Lisp programming language.
Your favorite standard library function/macro/feature from your favorite Lisp dialect that you want to see in your favorite non-Lisp programming language.
Once you tell these 3 things to the angel, she will magically add your chosen feature to your chosen non-Lisp programming language.
"favorite Lisp dialect": Scheme (Guile, Gambit, and MIT/GNU)
"favorite non-Lisp programming language": Haskell
"favorite standard library function/macro/feature": homoiconicity, i.e. both code syntax and data structures built from S-expression, which makes features like syntax-case feature possible, and the ability to implement declarative domain specific languages with Haskell-like type checking on large parts of your program at compile time. If every language would like this, my life would be soooo much easier and less stressful.
One thing I hate about other languages is complicated syntax that makes it difficult or impossible to do macro-programming. S-expressions are a minimalist syntax that allows lisp to be well-adapted to most any use case, and features like defmacro or syntax-case are very well designed mechanisms for doing exactly that. Other languages like Python and JavaScript have macro-programming implementations but they are so hacky and not very well designed compared to most Lisps, which have the feature built right into the language.