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module Prism
# A class that knows how to walk down the tree. None of the individual visit
# methods are implemented on this visitor, so it forces the consumer to
# implement each one that they need. For a default implementation that
# continues walking the tree, see the Visitor class.
class BasicVisitor
# Calls `accept` on the given node if it is not `nil`, which in turn should
# call back into this visitor by calling the appropriate `visit_*` method.
def visit(node)
# @type self: _Visitor
node&.accept(self)
end
# Visits each node in `nodes` by calling `accept` on each one.
def visit_all(nodes)
# @type self: _Visitor
nodes.each { |node| node&.accept(self) }
end
# Visits the child nodes of `node` by calling `accept` on each one.
def visit_child_nodes(node)
# @type self: _Visitor
node.compact_child_nodes.each { |node| node.accept(self) }
end
end
# A visitor is a class that provides a default implementation for every accept
# method defined on the nodes. This means it can walk a tree without the
# caller needing to define any special handling. This allows you to handle a
# subset of the tree, while still walking the whole tree.
#
# For example, to find all of the method calls that call the `foo` method, you
# could write:
#
# class FooCalls < Prism::Visitor
# def visit_call_node(node)
# if node.name == "foo"
# # Do something with the node
# end
#
# # Call super so that the visitor continues walking the tree
# super
# end
# end
#
class Visitor < BasicVisitor
<%- nodes.each_with_index do |node, index| -%>
<%= "\n" if index != 0 -%>
# Visit a <%= node.name %> node
alias visit_<%= node.human %> visit_child_nodes
<%- end -%>
end
end
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