codepreneur · September 14, 2015 07:38 · May 19, 2015 · Apr 19, 2015 · Apr 19, 2015 · Apr 19, 2015
diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -46,7 +46,7 @@
   `)
 })();
 
-$('#el').on(click, function clickHandler () {
+$('#el').on('click', function clickHandler () {
   console.log(`
   This is an example of a lambda expression that is not anonymous. As you can
   see, it clearly has a name, clickHandler, which can be used inside the

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -2,7 +2,7 @@
 // Anonymous function means "function without a name".
 
 // This is one of the relatively few cases where the Wikipedia definition of
-// a word, while not entirely wrong, is misleading. Lambdas and Anonymous
+// a word, while not entirely wrong, is misleading. Lambdas and anonymous
 // functions are distinct ideas.
 
 // These ideas are commonly confused because in many programming languages

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -8,6 +8,9 @@
 // These ideas are commonly confused because in many programming languages
 // all lambdas are anonymous or vise verse.
 
+// In JavaScript, not all lambdas are anonymous, and not all anonymous
+// functions are lambdas, so the distinction has some practical meaning.
+
 (function () {
   console.log(`
   Some people mistakenly think that "lambda" and "anonymous function" have

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -5,6 +5,9 @@
 // a word, while not entirely wrong, is misleading. Lambdas and Anonymous
 // functions are distinct ideas.
 
+// These ideas are commonly confused because in many programming languages
+// all lambdas are anonymous or vise verse.
+
 (function () {
   console.log(`
   Some people mistakenly think that "lambda" and "anonymous function" have

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -1,9 +1,9 @@
 // TL;DR - Lambda means "function used as data".
 // Anonymous function means "function without a name".
 
-// One of the relatively few cases where the Wikipedia definition of a word,
-// while not entirely wrong, is misleading. Lambdas and Anonymous functions
-// are distinct ideas.
+// This is one of the relatively few cases where the Wikipedia definition of
+// a word, while not entirely wrong, is misleading. Lambdas and Anonymous
+// functions are distinct ideas.
 
 (function () {
   console.log(`

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -2,7 +2,7 @@
 // Anonymous function means "function without a name".
 
 // One of the relatively few cases where the Wikipedia definition of a word,
-// while not entirely wrong is misleading. Lambdas and Anonymous functions
+// while not entirely wrong, is misleading. Lambdas and Anonymous functions
 // are distinct ideas.
 
 (function () {

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -1,5 +1,5 @@
-// TL;DR - Lambda means "function used as data."
-// Anonymous function means "function without a name."
+// TL;DR - Lambda means "function used as data".
+// Anonymous function means "function without a name".
 
 // One of the relatively few cases where the Wikipedia definition of a word,
 // while not entirely wrong is misleading. Lambdas and Anonymous functions

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -1,3 +1,6 @@
+// TL;DR - Lambda means "function used as data."
+// Anonymous function means "function without a name."
+
 // One of the relatively few cases where the Wikipedia definition of a word,
 // while not entirely wrong is misleading. Lambdas and Anonymous functions
 // are distinct ideas.

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -1,3 +1,7 @@
+// One of the relatively few cases where the Wikipedia definition of a word,
+// while not entirely wrong is misleading. Lambdas and Anonymous functions
+// are distinct ideas.
+
 (function () {
   console.log(`
   Some people mistakenly think that "lambda" and "anonymous function" have

diff --git a/lambda-not-anon.js b/lambda-not-anon.js
@@ -0,0 +1,48 @@
+(function () {
+  console.log(`
+  Some people mistakenly think that "lambda" and "anonymous function" have
+  the same meaning. Let's clear that up.
+
+  In computer science, the most important, defining characteristic of a lambda
+  expression is that it is used as data. That is, the function is passed as
+  an argument to another function, returned as a value from a function, or
+  assigned to variables or data structures.
+
+  This is basically the definition of a first class function. In JavaScript, you
+  can use any function as a lambda expression because functions are first class.
+
+  However, that does not mean that all JavaScript functions are therefore lambda
+  expressions. For instance, this expression defines a function which gets
+  immediately invoked and then dropped on the floor rather than passed,
+  exported, or assigned. In other words, the function is not used as data.
+  Instead, it's used for a side-effect (logging this text to the console).
+
+  Conceptually, this is more akin to imperative programming than functional
+  programming, and thinking of this function as a lambda would add zero useful
+  meaning to your understanding of it.
+
+  This distinction is not essential, but is a useful concept when you're
+  learning functional programming. In other words, if you understand this
+  distinction, you have a deeper understanding of what the word "lambda" means
+  in both functional programming and lambda calculus (which are closely
+  related).
+
+  It is possible to use functional language features like first-class functions
+  in an imperative style, but that adds nothing interesting to your grasp of the
+  language, or your grasp of why lambda expressions exist in the first place.
+  `)
+})();
+
+$('#el').on(click, function clickHandler () {
+  console.log(`
+  This is an example of a lambda expression that is not anonymous. As you can
+  see, it clearly has a name, clickHandler, which can be used inside the
+  function for the purpose of recursion (also an important concept in functional
+  programming).
+
+  It is a lambda expression because of the semantic use -- it's being passed
+  to another function as data. The .on() function is using the function as
+  an argument -- in other words, communicated as a message (i.e. functions as
+  data).
+  `);
+});