This are extensions!!

{{person.name}}
{{person.age}}

{{person\.name}}
{{person\.name\=Fred}}

{{#person.name=Jon}}
Hello Jon
{{/person.name=Jon}}

{{^person.name=Jon}}
No Jon? Hey Jon...
{{/person.name=Jon}}

{{^person.name=Harry}}
No Harry? Hey Calahan...
{{/person.name=Harry}}

{{#person\.name=Fred}}
Hello Fred
{{/person\.name=Fred}}

{{^person\.name=Fred}}
No Fred? Hey Fred...
{{/person\.name=Fred}}

{{#person\.name\=Fred=The other Fred.}}
Hello Fred#2
{{/person\.name\=Fred=The other Fred.}}

{{^person\.name\=Fred=The other Fred.}}
No Fred#2? Hey Fred#2...
{{/person\.name\=Fred=The other Fred.}}

{{#persons}}
{{#lang=!fr}}Hello {{name}}, {{age}} years{{/lang=!fr}}
{{#lang=fr}}Salut {{name}}, {{age}} ans{{/lang=fr}}
{{/persons}}

{{#persons}}
{{name}}: {{age=24}}/{{age}}/{{age=!27}}
{{/persons}}

{{#fellows.*}}
{{*}}: {{age=24}}/{{age}}/{{age=!27}}
{{/fellows.*}}

{{#*}}
 (1) {{*}}: {{.}}
   {{#*}}
     (2) {{*}}: {{.}}
     {{#*}}
       (3) {{*}}: {{.}}
     {{/*}}
   {{/*}}
{{/*}}