<code>len(x)</code> is <a href="#Length_and_capacity">constant</a>,
the range expression is not evaluated.
</p>

<p>
Function calls on the left are evaluated once per iteration.
For each iteration, iteration values are produced as follows
if the respective iteration variables are present:
</p>

<pre class="grammar">

                   {
                    "upgrade_type": "CONNECT",
                    "connect_config": {}
                   }
                  ]
                 },
                 "typed_per_filter_config": {
                  "connect_authority": {
                   "@type": "type.googleapis.com/udpa.type.v1.TypedStruct",
                   "type_url": "type.googleapis.com/io.istio.http.connect_authority.Config",