README.md

Ruby-Specific API

This is not a comprehensive list, but a curated list of examples to showcase the ruby-specific API.

IMPORTANT

As of today, there's a bug in tree-sitter that prevents correct access to a node's child field_name correctly.

Keep that in mind while reading the next sections.

Node

For a give parse tree, that looks something like:

(method name: (identifier) parameters: (method_parameters (identifier) (identifier)) ...

We're oftern interested in accessing the children name and parameters field names. Unnamed children usually represent tokens of syntax. If you're writing a syntax highlighter, then yes this is very important. But if you're producing an AST from the parse tree, then you're more interested in the named children which are usually attached to fields.

Iterating over children

It's often more interesting to iterate over named node so:

node.each do |field, child|
  puts "#{field}: #{child}"
end

# => name: (identifier)
# => parameters: (method_parameters ...

Will iterate through named childs, and send back the attached field name.

See: each_child, each_named_child.

Accessing children by field name

You can call [] or just node.field_name; we use mehod_missing to allow you to access a child_by_field_name to enable the latter syntax.

node[:name] # or even
node.name