Rust Programming Cookbook

How it works...

In step 2 of this recipe, we define a macro that explicitly provides the different patterns that the engine can match to. Specifically, the alphanumeric characters are limited to ,, ;, and =>. While this allows Ruby-style map initialization, it also limits the elements that a DSL can have. However, macros are still great for creating a more expressive way to deal with situations. In step 6 and step 7, we show a way to create a web request handler using a more expressive way than the usual chained function calls. Step 4 and step 5 show the usage of the arrow (=>) inside macros and step 8 ties it all together by running the tests.

In this recipe, we created matching arms for the macro invocation to use, where the arms use a ...