1 files changed, 24 insertions, 0 deletions
diff --git a/proc.c b/proc.c
index a3dcc0c970..a994c3157b 100644
--- a/proc.c
+++ b/proc.c
@@ -107,6 +107,30 @@ proc_clone(VALUE self)
     return procval;
 }
 
+/*
+ * call-seq:
+ *   prc.lambda? => true or false
+ *
+ * Returns true for a Proc object which argument check is rigid.
+ * Such procs are typically generated by lambda.
+ *
+ *   lambda {}.lambda?          => true
+ *
+ *   proc {}.lambda?            => false
+ *   Proc.new {}.lambda?        => false
+ *
+ *   def m() end
+ *   method(:m).to_proc.lambda? => true
+ *
+ *   def n(&b) b.lambda? end
+ *   n {}                       => false
+ *   n(&lambda {})              => true
+ *   n(&method(:m))             => true
+ *   n(&proc {})                => false
+ *   n(&Proc.new {})            => false
+ *
+ */
+
 static VALUE
 proc_lambda_p(VALUE procval)
 {