Hands-On Design Patterns and Best Practices with Julia

Writing our first macro

Macros are defined in a similar way to how functions are defined, except that the macro keyword is used instead of the function keyword.

We should also keep in mind that a macro must return expressions. Let's create our first macro. This macro returns an expression object that contains a for loop, as follows:

macro hello()    return :(    for i in 1:3        println("hello world")    end    )end

Invoking the macro is as easy as calling it with the @ prefix. Refer to the following code:

Unlike functions, macros may be called without using parentheses. So we can just do the following:

Fantastic! We have now written our first macro. While ...