The Ruby LSP supports semantic highlighting. This feature informs editors about the right token types for each part of the code to allow for rich and accurate highlighting. The strategy taken by the Ruby LSP is to only return tokens for syntax that is ambiguous in Ruby (as opposed to all existing tokens) to optimize for performance.
An example of ambiguous syntax in Ruby are local variables and method calls. If you look at this line in isolation:
fooit is not possible to tell if foo is a local variable or a method call. It depends on whether foo was assigned to
something before or not. This is one scenario where semantic highlighting removes the ambiguity for themes, returning
the correct token type by statically analyzing the code.
To enhance a theme's Ruby syntax highlighting using the Ruby LSP, check the information below. You may also want to check out the Spinel theme as an example, which uses all of the Ruby LSP's semantic highlighting information.
According to the LSP specification, language servers can either use token types and modifiers from the default list or contribute new semantic tokens of their own. Currently, the Ruby LSP does not contribute any new semantic tokens and only uses the ones contained in the default list.
| Syntax | Type.Modifier | Note |
|---|---|---|
Sorbet annotation methods such as let or cast |
type | Not every annotation is handled |
| Method calls with any syntax | method | |
| Constant references (including classes and modules) | namespace | We don't yet differentiate between module and class references |
| Method definition | method.declaration | |
| self | variable.default_library | |
| Method, block and lambda arguments | parameter | |
| Class declaration | class.declaration | |
| Module declaration | class.declaration |