You can prefix expressions with a single quote (') to change how they are evaluated: instead of reducing the expression as normal, its structural components are each evaluated individually, and the resulting expression is a value at runtime.

The primary use of quotation is when building lists:

numbers : '(1 2 3)

Without the quote, the expression would be interpreted as a function call, which is invalid for numbers.

Unlike Lisp, quoting in Wipple is "shallow" and only uses the structural form of the value being directly quoted. This means that '((f x) (f y)) evaluates f x and f y. You can quote the list twice to preserve the entire structure:

f : x -> x
x : 1
y : 2

'((f x) (f y)) :: List Number
''((f x) (f y)) :: List (List Name)

Names have no substructure, so you only need to quote them once:

'x :: Name

Quoting numbers and text has no effect. Blocks and attributes are compile-time constructs and can't be quoted.