Elixir grammar for the [Lezer](https://lezer.codemirror.net) parser system.
npm install lezer-elixirElixir grammar for the Lezer parser system.
This grammar is based directly on tree-sitter-elixir
and closely mirrors its syntax tree and decisions. All the test cases are adapted from there
as well. Refer to the corresponding repository for further documentation.
The Elixir syntax tree is very generic. Most of the language built-ins, such as a function
definition, are no different than user-defined functions. It is only for the purpose
of highlighting, where it makes sense to distinguish certain keywords.
tree-sitter allows pattern matching on arbitrary fragments of the syntax tree, which is
flexible enough to correctly tag nodes for highlighting in all cases. On the other hand,
in Lezer the highlighting queries are more strict, for performance reasons. Under these
restrictions, we need a more specialized syntax tree that, for example, uses separate
nodes for function definition call and regular function call. Additionally, Lezer does
not support annotating nodes with "fields", for example, to distinguish between operator
left and right expression. In cases where we need those, an explicit nodes are required.
Given that, this grammar describes a syntax tree that is a superset of the tree-sitter
one. The following additional nodes are present:
- Identifier specializations
- SpecialIdentifier (__MODULE__)
- UnderscoredIdentifier (_x)
- Call specializations
- FunctionDefinitionCall (def fun(x), do: 1)
- KernelCall (if) - in addition to Call
- UnaryOperator specializations
- AtOperator (@x)
- DocOperator (@doc "...")
- CaptureOperator (&fun/1)
- CaptureOperand (&1)
- BinaryOperator specializations
- WhenOperator (left when right)
- PipeOperator (left |> right)
- Sigil specializations
- StringSigil (~s"string", ~S"string")
- named operator groups
- Operator (+)
- WordOperator (and)
- explicitly included tokens
- do, end, fn, after, else, catch, rescue
- all brackets
- fields:
- Right node in WhenOperator, PipeOperator and Dot to distinguish the left and
right operand (note that this is enough to make the distinction, we don't need Left,
which would result in more conflicts when introduced)
- we do not need an explicit "target" node for calls, because arguments are already
separated under the Arguments node, hence anything else on that level is the target
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