Every piece of code in Lumen is an expression, and expressions can be evaluated to give values. Lumen has a few kinds of expressions that evaluate to themselves:
Lists contain other values, and are written by enclosing expressions in parentheses. Operators are called by placing them at the beginning of a list expression, and list values can be constructed using the list operator:
Variables are declared using define and define-global. Variables declared with define are available for use anywhere in subsequent expressions in the same scope, and define-global makes them globally available.
You can see that let accepts a list of names and values, called bindings, or it can work with a single binding. More than one expression can follow the bindings, which works like do: