build: we need the containers package
Oreole.Language.Atom: opted for a nicer Show instance
Oreole.Language.Atom: grouped the Atom parsers into one
Oreole.Language.Operator: support for operators and their precedence
Oreole.Language.Space: whitespace and line breaks, maybe move this into an auxiliary module at a later point
Oreole.Language.Term: support for terms (operations, parentheses, etc.)
Main: a use case for operators
Oreole.Language.Term: docs + better names
Oreole.Language.Space: docs + descriptive names
Oreole.Language.Aux: auxiliary functions
Oreole.Language.Space: label parsers
Oreole.Language.Aux: make use of it in other modules