A printer transforms a value to into a document. A printer is said to be safe if it produces a document that is unambiguously delimited (e.g., delimited with parentheses). It is unsafe otherwise.

int is an integer literal printer. It is safe.

bool is a Boolean literal printer. It is safe.

char is a character literal printer. It is safe.

string is a string literal printer. It is safe.

option is an option printer. It is safe.

result is a result printer. It is safe.

pair is a pair printer. It is safe.

list is a list printer. It is safe.

array is an array printer. It is safe.

parens encloses its argument within a pair of parentheses. It is safe. If the document thus obtained does not fit a single line, then it is split over three lines and its content is indented by two spaces.

apply doc docs constructs an OCaml application of doc to the list of arguments docs. The arguments are separated with spaces, and if the whole application does not fit on a line, then a flowing style is adopted, inserting a line break where necessary. This combinator is unsafe: the application is not parenthesized.

assert_ doc constructs an OCaml assertion, that is, an application of the variable assert to the document doc, surrounded with parentheses. This combinator is unsafe: the assertion is not parenthesized.

comment doc prints the document doc inside a comment (preceded with a breakable space). It is safe.

candidate_finds doc prints the document doc inside a comment of the form (* candidate finds _ *). See e.g. the demo demos/working/bag for an example of its use. It is safe.