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Syntax module for Option. This is intended to be opened locally in functions which use option for control-flow. Within the scope of this module, the code can include binding operators, leading to a let-style syntax.
fail is None. It is also an alias for Option.none.
val return_unit : unit option
return_unit is Some ().
val return_nil : 'a list option
return_nil is Some [].
val return_true : bool option
return_true is Some true.
val return_false : bool option
return_false is Some false.
Note that we do not provide return_some nor return_none. Both of these functions are possible but somewhat confusing and rarely useful in practice. If you need to carry options within a Option-monad computation (yielding to values of the type 'a option option), you need to do so by hand: return (Some …) and return None.