patch 7.4.1154
Problem:    No support for JSON.
Solution:   Add jsonencode() and jsondecode().  Also add v:false, v:true,
            v:null and v:none.
diff --git a/src/if_ruby.c b/src/if_ruby.c
index 96d9453..bb34de1 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -1032,6 +1032,11 @@
 		}
 	    }
 	}
+    }
+    else if (tv->v_type == VAR_SPECIAL)
+    {
+	if (tv->vval.v_number <= VVAL_TRUE)
+	    result = INT2NUM(tv->vval.v_number);
     } /* else return Qnil; */
 
     return result;