Hands-On Design Patterns and Best Practices with Julia

Passing expression arguments

It is important to emphasize that macro arguments are passed as expressions rather than values. It may look confusing for beginners because macros are invoked similarly to functions, but the behavior is completely different. 

Let's make sure that we fully understand what this means. When calling a function with a variable, the value of the variable is passed into the function. Consider the following sample code for a showme function:

Now, let's create a @showme macro that does nothing but display the argument in the console. We can then compare the results with the preceding code:

As we can see, the results from ...