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.

Defined Under Namespace

Classes: VisitMethodChecker, VisitMethodError, VisitMethodsChecker

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.valid_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 72

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

.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 86

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

  raise VisitMethodError, method_name
end

.visit_methods ⇒ Object

This method is here to help folks write visitors.

Within the given block, every method that is defined will be checked to ensure it’s a valid visit method using the BasicVisitor::visit_method method defined above.



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# File 'lib/syntax_tree/basic_visitor.rb', line 97

def visit_methods
  checker = VisitMethodsChecker.new
  extend(checker)
  yield
  checker.disable!
end

Instance Method Details

#visit(node) ⇒ Object 



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# File 'lib/syntax_tree/basic_visitor.rb', line 105

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

#visit_all(nodes) ⇒ Object 



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# File 'lib/syntax_tree/basic_visitor.rb', line 109

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 113

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