Class: SyntaxTree::BasicVisitor

Inherits:
Object
  • Object
show all
Defined in:
lib/syntax_tree/basic_visitor.rb

Overview

BasicVisitor is the parent class of the Visitor class that provides the ability to walk down the tree. It does not define any handlers, so you should extend this class if you want your visitor to raise an error if you attempt to visit a node that you don’t handle.

Direct Known Subclasses

Visitor, Visitor::FieldVisitor

Defined Under Namespace

Classes: VisitMethodChecker, VisitMethodError

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.visit_method(method_name) ⇒ Object

This method is here to help folks write visitors.

It’s not always easy to ensure you’re writing the correct method name in the visitor since it’s perfectly valid to define methods that don’t override these parent methods.

If you use this method, you can ensure you’re writing the correct method name. It will raise an error if the visit method you’re defining isn’t actually a method on the parent visitor.

Raises:



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# File 'lib/syntax_tree/basic_visitor.rb', line 53

def visit_method(method_name)
  return if visit_methods.include?(method_name)

  raise VisitMethodError, method_name
end

.visit_methods ⇒ Object

This is the list of all of the valid visit methods.



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# File 'lib/syntax_tree/basic_visitor.rb', line 60

def visit_methods
  @visit_methods ||=
    Visitor.instance_methods.grep(/^visit_(?!child_nodes)/)
end

Instance Method Details

#visit(node) ⇒ Object 



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# File 'lib/syntax_tree/basic_visitor.rb', line 66

def visit(node)
  node&.accept(self)
end

#visit_all(nodes) ⇒ Object 



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# File 'lib/syntax_tree/basic_visitor.rb', line 70

def visit_all(nodes)
  nodes.map { |node| visit(node) }
end

#visit_child_nodes(node) ⇒ Object 



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# File 'lib/syntax_tree/basic_visitor.rb', line 74

def visit_child_nodes(node)
  visit_all(node.child_nodes)
end