Beyond Pretty-Printing: Galley Concepts in Document Formatting Combinators

Galleys have been introduced by Jeff Kingston as one of the key concepts underlying his advanced document formatting system Lout. Although Lout is built on a lazy functional programming language, galley concepts are implemented as part of that language and defined only informally. In this paper we present a first formalisation of document formatting combinators using galley concepts in the purely functional programming language Haskell.