Hands-On Design Patterns and Best Practices with Julia

Using closure to hide private variables and functions away

Our goal is to hide the global constant, sites, and the helper function, index_site!, such that they are not visible in the public API. To achieve that, we can utilize let blocks.

In the body of the module, we can wrap all of the functions inside a let block, as follows:

Now, let's see what has been changed:

• The sites constant has been replaced by a bound variable at the beginning of the let block. The variables in a let block are bound only in the scope of the block and are not visible to the outside world.
• The functions that need to be exposed to the API are prefixed with the ...