Programming Definitions

definitions.txt

Set: Unordered list of unique elements.
Array: Ordered list of elements.
HashMap: Unordered list of key-value pairs where the keys are unique.
  (Note: this has many different names.
    Hash in Ruby, Perl
    Dictionary in Python (keys must be immutable)
    Object in Javascript (value functions can introspect)
    Map in Clojure
    HashMap in Java
    Associative Array in PHP,Perl,Wikipedia
    Key-Value Store in document databases
    Record in C, databases
Binding: Explicit list of variables and the values they represent. (sometimes ordered)
  e.x. {a: 3, b: "Jim"}
Function: Named list of instructions which takes a binding and returns a value
  function add (x, y) {
   // name-^^^  ^^^^-binding
    return x + y;
  // value-^^^^^
  }

Predicate Function: A function which returns true or false
Arity: Number of parameters of a function
Reduction Function: A function which combines a value into an aggregate
  e.x. (fn [total n] (+ total n))
       (fn [coll elem] (conj coll elem))
Higher-order function: A function which takes a function as a parameter or returns a function as a result
  e.x.
    function do(f, x) {
            //  ^-takes a function
      return f(x);
    }
    do(Math.sqrt, 3); // would return Math.sqrt(3)
    
    function adder(x) {
      return function (y) { return x + y; };
          // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-returns function
    }