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module Prism
# A compiler is a visitor that returns the value of each node as it visits.
# This is as opposed to a visitor which will only walk the tree. This can be
# useful when you are trying to compile a tree into a different format.
#
# For example, to build a representation of the tree as s-expressions, you
# could write:
#
# class SExpressions < Prism::Compiler
# def visit_arguments_node(node) = [:arguments, super]
# def visit_call_node(node) = [:call, super]
# def visit_integer_node(node) = [:integer]
# def visit_program_node(node) = [:program, super]
# end
#
# Prism.parse("1 + 2").value.accept(SExpressions.new)
# # => [:program, [[[:call, [[:integer], [:arguments, [[:integer]]]]]]]]
#
class Compiler
# Visit an individual node.
def visit(node)
node&.accept(self)
end
# Visit a list of nodes.
def visit_all(nodes)
nodes.map { |node| node&.accept(self) }
end
# Visit the child nodes of the given node.
def visit_child_nodes(node)
node.compact_child_nodes.map { |node| node.accept(self) }
end
<%- nodes.each_with_index do |node, index| -%>
<%= "\n" if index != 0 -%>
# Compile a <%= node.name %> node
alias visit_<%= node.human %> visit_child_nodes
<%- end -%>
end
end
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