1 files changed, 63 insertions, 0 deletions
diff --git a/sample/prism/visit_nodes.rb b/sample/prism/visit_nodes.rb
new file mode 100644
index 0000000000..5ba703b0a3
--- /dev/null
+++ b/sample/prism/visit_nodes.rb
@@ -0,0 +1,63 @@
+# This script visits all of the nodes of a specific type within a given source
+# file. It uses the visitor class to traverse the AST.
+
+require "prism"
+require "pp"
+
+class CaseInsensitiveRegularExpressionVisitor < Prism::Visitor
+  def initialize(regexps)
+    @regexps = regexps
+  end
+
+  # As the visitor is walking the tree, this method will only be called when it
+  # encounters a regular expression node. We can then call any regular
+  # expression -specific APIs. In this case, we are only interested in the
+  # regular expressions that are case-insensitive, which we can retrieve with
+  # the #ignore_case? method.
+  def visit_regular_expression_node(node)
+    @regexps << node if node.ignore_case?
+    super
+  end
+
+  def visit_interpolated_regular_expression_node(node)
+    @regexps << node if node.ignore_case?
+
+    # The default behavior of the visitor is to continue visiting the children
+    # of the node. Because Ruby is so dynamic, it's actually possible for
+    # another regular expression to be interpolated in statements contained
+    # within the #{} contained in this interpolated regular expression node. By
+    # calling `super`, we ensure the visitor will continue. Failing to call
+    # `super` will cause the visitor to stop the traversal of the tree, which
+    # can also be useful in some cases.
+    super
+  end
+end
+
+result = Prism.parse_stream(DATA)
+regexps = []
+
+result.value.accept(CaseInsensitiveRegularExpressionVisitor.new(regexps))
+regexps.each do |node|
+  print node.class.name.split("::", 2).last
+  print " "
+  puts PP.pp(node.location, +"")
+
+  if node.is_a?(Prism::RegularExpressionNode)
+    print "  "
+    p node.unescaped
+  end
+end
+
+# =>
+# InterpolatedRegularExpressionNode (3,9)-(3,47)
+# RegularExpressionNode (3,16)-(3,22)
+#   "bar"
+# RegularExpressionNode (4,9)-(4,15)
+#   "bar"
+
+__END__
+class Foo
+  REG1 = /foo/
+  REG2 = /foo #{/bar/i =~ "" ? "bar" : "baz"}/i
+  REG3 = /bar/i
+end