Ractive.components.a = Ractive.extend({ template: 'I am A {{foo}}' });
Ractive.components.b = Ractive.extend({ template: 'I am B {{foo}}' });
Ractive.components.c = Ractive.extend({ template: 'I am C {{foo}}' });

Ractive.components.dynamic = Ractive.extend({
    template: '<component/>',
    components: {
        component: function() {
            return this.get('name');
        }
    },
    oninit: function(){
        this.observe('name', function(){
            this.reset();
        }, { init: false});
    }
});


var r = new Ractive({
    el: document.body,
    template: '#template',
    data: {
        foo: 'foo',
        list: ['a', 'b', 'c'],
        name: 'a'
    }
});

<script src="http://cdn.ractivejs.org/latest/ractive.js"></script>
<script id='template' type='text/ractive'>
   
    {{#each list}}
    <input type='radio' name='{{name}}' value='{{.}}'>{{.}}
    {{/each}}
    <br>
    <dynamic name='{{name}}'/>
       
</script>