Simple shapes

Simple shapes are Smithy’s primitives — the atoms everything else is built from:

Category	Shapes
Text	string, blob (binary)
Numbers	byte, short, integer, long, float, double, bigInteger, bigDecimal
Other	boolean, timestamp, document

The prelude vs. your own names

You can use a primitive directly — the built-in String, Integer, and friends live in the prelude (the smithy.api namespace, always in scope). But you can also give a primitive your own name, creating a distinct, referenceable type:

$version: "2.0"

namespace example

string CityName
integer Population
boolean IsCapital
timestamp FoundedAt
blob FlagImage

A named shape like CityName is its own type even though it’s “just a string” — later you can attach constraints to it (see the Traits lesson), and codegen can treat it distinctly.

Two rules to remember

• One namespace per file, declared right after $version.
• Shape names start with an uppercase letter (CityName, not cityName).

Your turn