Compound binding support for I18N-target attributes.
attr="Compound binding attribute has [[bound.value]] {{parameters}} in the value string"
"{{i18nFormat(attrId.0,bound.value,parameters)}}"
[ "Compound binding attribute has {1} {2} in the value string", "[[bound.value]]", "{{parameters}}" ]
attr2="Compound binding attribute has [[f1(bound.value)]] {{f2(parameters)}} in the value string"
"{{attrId.0}}[[f1(bound.value)]]{{attrId.2}}{{f2(parameters)}}{{attrId.4}}"
[ "Compound binding attribute has ", "[[f1(bound.value)]]", " ", "{{f2(parameters)}}", " in the value string" ]