Is there a function that returns a list of values with specific type in OCaml?

In Haskell, using listify with Data can extract values of a specific type from a deeply nested structure without lots of getters. For example, with the following code:

{-# LANGUAGE DeriveDataTypeable #-}{-# LANGUAGE OverloadedStrings  #-}module Lib  ( john  , listStrings  ) whereimport           Data.Dataimport           Data.Generics.Schemesimport           Data.Textdata Person = Person  { name    :: Name  , address :: Address  } deriving (Data, Show)data Name = Name  { firstName :: Text  , lastName  :: Text  } deriving (Data, Show)data Address = Address  { addressLine :: Text  , city        :: Text  , province    :: Text  , country     :: Text  } deriving (Data, Show)john :: Personjohn =  Person    { name = Name {firstName = "John", lastName = "Smith"}    , address =        Address          { addressLine = "1-2-3 Nantoka-kantoka-machi"          , city = "Nishinomiya"          , province = "Hyogo"          , country = "Japan"          }    }listStrings :: Person -> [Text]listStrings = listify (const True)

listStrings john returns a list of Texts in john.

ghci> listStrings john["John","Smith","1-2-3 Nantoka-kantoka-machi","Nishinomiya","Hyogo","Japan"]

Is there something like this in OCaml?

Context

I'm writing a Coq code formatter, and having difficulty pretty-printing notations (e.g., _ = _.) The node constructor for notations is CNotation in constr_expr_r.

Coq's OCaml API provides find_notation_printing_rule which takes a value in CNotation and returns the printing rule for the notation, but I also don't understand what the returned rule means. This led me to write a printing rule dumper; a program that takes a Coq code as an input, extracts notations from the code, and dumps the notations with printing rules and other useful information. For the extraction phase, I need a function like listify to get CNotations from the code.