R for Data Science Cookbook

Working with lexical scoping

Lexical scoping, also known as static binding, determines how a value binds to a free variable in a function. This is a key feature that originated from the scheme functional programming language, and it makes R different from S. In the following recipe, we will show you how lexical scoping works in R.

Getting ready

Ensure that you completed the previous recipes by installing R on your operating system.

How to do it...

Perform the following steps to understand how the scoping rule works:

1. First, we create an x variable, and we then create a tmpfunc function with x+3 as the return:

   >x<- 5
   >tmpfunc<- function(){
   + x + 3
   + }
   >tmpfunc()
   [1] 8
   

2. We then create a function named parentfunc with a childfunc nested function and see ...