Selecting a Builtin to add

First, find a Builtin that hasn’t been implemented. This is pretty easy. Generally you start out having a desire for a specific function or symbol. However if not, there are github feature requests with the label “New Builtin Function or Variable”.

Also look for TODO at the bottom of the newer sections/modules for missing builtin functions for that particular class or function.

Below are a few examples of actual Mathics3 Builtins that we have added.

As we added these Builtins, we recorded the steps that were taken. We ordered the list above to go from the simpile to more advanced.

See also Tutorial: Adding a new Mathics3 Function.