FPC

Speaking of a LISP

100

This popular Lisp dialect is known for targeting the JVM and interacting well with Java code.

Clojure

200

This form of list interpolation allows one to interpolate code and data.

Quasi-quoting

300

Branched from the Scheme family, this Lisp dialect was built to apply all four major programming paradigms in one language.

Racket

400

This special data value originated in Lisp and is used today in many languages such as Ruby and Common Lisp to represent emptiness or falsehood.

nil

500

This datatype, made popular by early Lisps, is capable of supporting arbitrarily large numbers, regardless of the underlying architecture.

Bignum

Thinking with Functions

100

This popular optimization technique allows the compiler to use constant stack space for certain recursive functions.

Tail call optimization

200

This programming technique uses functions passed as arguments or returned from other functions to make code more generally useful.

Higher-order functions

300

Seen in most modern functional languages, This function applies a given function to each element of a list.

map

400

This special syntactic construct in Ruby accomplishes a similar task to lambdas but in a more imperative-friendly way.

Code blocks

500

A fork of APL, this rather peculiar language uses hooks, forks, and trains to allow more forms of function composition to be expressed.

J

Can your Language do This?

100

This built-in module adds many functional features such as partial application and folds to Python.

functools

200

Made popular by Haskell, this mathematical structure encompasses side effects and state into a simple data type.

Monads

300

This functional language is renowned for its concurrency abilities and its unique ability to spawn thousands of processes in an average program.

Erlang / Elixir

400

This concurrency model, used by modern languages like Io and Erlang, offers a cleaner, more problem-free approach to concurrency than threading.

Actor model

500

This rather strangely non-transitive Javascript operator was changed in Coffeescript to have more consistent behavior.

==

History of Functional Programming

100

This functional language feature was recently added to C++ and Java.

Lambda / Anonymous function

200

The first language to implement a garbage collector, this language is also credited with being the first functional programming language.

Lisp

300

This university was not only home to John McCarthy but was one of the first to use functional programming to develop AI.

MIT

400

Known for his work in combinatory logic, this American mathematician has at least three programming languages named after him.

Haskell Curry

500

Invented by Alonzo Church, this mathematical system is the basis for modern functional programming languages.

Lambda calculus

Esoteric Fun Facts

100

When C++ was invented, these special character sequences were added to accomodate coders with more limited keyboards.

Trigraphs / Digraphs

200

This weakly-typed language rather bizarrely yields the empty string upon evaluating the expression [] + [].

Javascript

300

When a built-in Perl operator is missing an argument, it frequently defaults to this special variable name.

$_

400

Aside from the empty string, this string is the only other "falsey" one in PHP.

"0"

500

This string is the result of evaluating the expression [101,109,112,116,121,32,115,116,114,105,110,103] in Erlang.

"empty string"