Named placeholders

String.Format references all args by index:
String.Format("{0} {1}", person.FirstName, person.LastName)

Smart.Format takes this a step further, and lets you use named placeholders instead:
Smart.Format("{FirstName} {LastName}", person)
In fact, Smart.Format supports several kinds of expressions:
Smart.Format("{FirstName.ToUpper} {LastName.ToLower}", person)

Nesting

In SmartFormat, you can use nesting to avoid repetition, such as:
Smart.Format("{User.Address:{Street}, {City}, {State} {Zip}}", data)

Nesting is often used with conditionals, plurals, and lists.

Nested Scope

When using nested placeholders, it is necessary to understand the scope that Reflection will use. A nested placeholder always starts off with the scope of the item that contains it.

The root scope for a template is arg0, meaning that {User.Address} is equivalent to data.User.Address.
Within the nested area, however, the "scope" has changed to User.Address, so nested expressions like {Street} are evaluated against User.Address.
To illustrate this, the following are all equivalent:
{User.Name} {User.Address.City} {User.Address.State} {User.Name} {User.Address:{City} {State}} {User:{Name} {Address:{City} {State}}}

Within any nested scope, you still have access to the outer scopes. For example:
{User.Address:{User.Name} {City} {State}}
Here, {User.Name}, which is in the root scope, is still accessible from within the nested User.Address scope.