Returns an AttributeView containing attributes defined on this tree.

# tree : Tree

tree.attributes["foo"]?
tree.attributes.size
tree.attributes.each do |name, value|
  # ...
end

# ...

Returns the index of the first character (not byte!) of this tree in the source string.

Returns a ChildrenView containing this tree's children.

# tree : Tree

tree.children["foo"] # => Array(Tree)
tree.children.size   # => Int
tree.children.each do |child|
  pp child # => Tree
end

# ...

Same as #dig?, but raises KeyError when it is impossible to follow one of the specified steps.

# tree : Tree
tree.dig("range", ":begin:", 0) # => Tree
tree.dig("foo", 0, "bar")       # => Tree

Follows deeper into the tree guided by steps. Returns the final tree, or nil if could not follow one of the steps.

The following types of steps are available:

• String: follow to a child whose id is equal to the given string.
• Int: follow to a child whose index in the parent tree is equal to the given integer.

# tree : Tree
tree.dig?("range", ":begin:", 0) # => Tree?
tree.dig?("foo", 0, "bar")       # => Tree?

Returns the index of the character (not byte!) immediately following the last character of this tree in the source string.

Same as #getattr but raises KeyError if the attribute cannot be found.

Returns the value of an attribute with the given name, if one is defined on this tree. Otherwise, returns nil. Attributes are usually defined using Rule.keep.

If you can't guarantee you'll need the read attribute's value prefer to use #attributes as it's going to return a string view into the source code which uses no memory.

Returns the capture id of this tree (see Sthx.capture).

Appends a multiline string view of this tree to io.

Converts tree objects to objects of type T using fn.

• Calls fn with leaf trees and an empty children array.
• Calls fn with branch trees and a children array of converted leaves.
• And so on, up to and including the root tree.

Returns the amount of characters (not bytes!) that this tree matches in the source string.

Returns true if this tree's capture id matches the given string object.

Returns true if this tree's position in the source string matches the given range object.

Returns true if this tree matches a predicate named by the first element of the given array object, whereas the predicate's arguments are specified by the rest of the elements in the array. Here is a list of possible predicates and their arguments:

• [:hasattr, <attribute name>, <expected attribute value>]: returns true if this tree has an attribute with the given name, and its value is equal to the expected value.

Returns true if this tree matches a predicate named by the given object symbol. Here is a list of possible predicate names:

• :empty: returns true if this tree is empty.

Returns true if any child of this tree #test?s true for object.

Returns true if all of head, rest #test? true for this tree.

# tree : Tree

tree.test?(
  "root", 0...19,
  {"nlist", 0...8,
   {"n", 0...1, [:hasattr, "value", "1"]},
   {"n", 2...4, [:hasattr, "value", "23"]},
   {"n", 5...6, [:hasattr, "value", "3"]},
   {"n", 7...8, [:hasattr, "value", "4"]}},
  {"nlist", 9...15,
   {"n", 9...10, [:hasattr, "value", "5"]},
   {"n", 11...13, [:hasattr, "value", "69"]},
   {"n", 14...15, [:hasattr, "value", "7"]}},
  {"nlist", 16...16, :empty}
)

# ...

Same as #inspect.