S is a string set.

s_of_list xs transforms the string list xs to a set.

M is a Map which keys are strings.

filter_map f xs is xs', a list which contains all elements where f resulted in Some _.

r >>= f is f a unless r is an Error, which is propagated. Monadic bind.

guard pred err is either Ok () (if pred holds), Error err otherwise.

foldM f a xs applies f to each element of xs, returns either Ok and the produced value, or Error.

foldS f a s applies f to each element of the set s, returns either Ok and the produced value, or Error.

Some String utilities implemented here to avoid external dependencies. This is a subset of Astring.

64 bit unsigned integer with explicit overflow behaviour (see Uint.succ).

LOGS is a subset of the Logs library, providing four log streams.

'a fmt is the signature for pretty printers.

pp_list pp is a pretty printer for a list (surrounded by square brackets, elements are separated by semicolon). The pp is be a pretty printer for list elements.

The sum type of possible file types we expect

A path is a list of strings

path_to_string path is String.concat "/" path.

• raises Invalid_argument

  if path includes either "." or ".."

string_to_path str is String.cuts "/" str.

An item is a type and its payload