| `[-,L]` | Creating top-level constructs in `IO`, such as `IORef`. This is, in general, considered to be bad style, but can sometimes be useful. |
| `[-,L]` | Using enso files like python is able to be for scripting work. The ability to write constructs at the top-level and just evaluate them. |
| `[M,H]` | The ability to generate structures and / types for a dataframe at compilation time, or the automatic generation of an API for a library. A key recognition is that dependent types and type-level execution replace much of the need to be able to query the type-checker and runtime while writing a syntactic macro. |
| `[M,H]` | Static metaprogramming (transformations from `AST -> AST`) to let users generate types and functions based on existing AST. There is the potential to want to be able to evaluate actions in `IO` while doing this, but it may not be necessary. |
| `[-,!]` | Dynamic metaprogramming to let users mutate program state at runtime (e.g. changing atom shapes, function definitions), also known as 'monkey patching'. This is not something we want in the language, but we do perhaps want the ability to do so on values of type `Dynamic`. |
| `[M,H]` | 'Remembering' things when compiling a file, such as remembering all structures marked by an `AST` annotation. An example use case for a mechanism like this is to generate pattern matches for all possible `AST` types. This can be done by letting macros write to a per-file peristent block of storage that could be serialised during precompilation. |
| `[M,H]` | Grouping of macros (e.g. `deriveAll = derive Ord Debug Show`). This can be easily handled by doing discovery on functions used as macros, and treating it as a macro as well. |
| `[?,M]` | Method-missing magic, akin to ruby. This is likely able to be handled using other, existing language mechanisms. |
