1 files changed, 49 insertions, 0 deletions
diff --git a/lib/irb/command/measure.rb b/lib/irb/command/measure.rb
new file mode 100644
index 0000000000..f96be20de8
--- /dev/null
+++ b/lib/irb/command/measure.rb
@@ -0,0 +1,49 @@
+module IRB
+  # :stopdoc:
+
+  module Command
+    class Measure < Base
+      include RubyArgsExtractor
+
+      category "Misc"
+      description "`measure` enables the mode to measure processing time. `measure :off` disables it."
+
+      def initialize(*args)
+        super(*args)
+      end
+
+      def execute(arg)
+        if arg&.match?(/^do$|^do[^\w]|^\{/)
+          warn 'Configure IRB.conf[:MEASURE_PROC] to add custom measure methods.'
+          return
+        end
+        args, kwargs = ruby_args(arg)
+        execute_internal(*args, **kwargs)
+      end
+
+      def execute_internal(type = nil, arg = nil)
+        # Please check IRB.init_config in lib/irb/init.rb that sets
+        # IRB.conf[:MEASURE_PROC] to register default "measure" methods,
+        # "measure :time" (abbreviated as "measure") and "measure :stackprof".
+
+        case type
+        when :off
+          IRB.unset_measure_callback(arg)
+        when :list
+          IRB.conf[:MEASURE_CALLBACKS].each do |type_name, _, arg_val|
+            puts "- #{type_name}" + (arg_val ? "(#{arg_val.inspect})" : '')
+          end
+        when :on
+          added = IRB.set_measure_callback(arg)
+          puts "#{added[0]} is added." if added
+        else
+          added = IRB.set_measure_callback(type, arg)
+          puts "#{added[0]} is added." if added
+        end
+        nil
+      end
+    end
+  end
+
+  # :startdoc:
+end