Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!
If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.
module Pat: sig .. end
val mk : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern_desc -> Parsetree.pattern
val attr : Parsetree.pattern -> Parsetree.attribute -> Parsetree.pattern
val any : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> unit -> Parsetree.pattern
val var : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.str -> Parsetree.pattern
val alias : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern -> Ast_helper.str -> Parsetree.pattern
val constant : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Asttypes.constant -> Parsetree.pattern
val interval : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Asttypes.constant -> Asttypes.constant -> Parsetree.pattern
val tuple : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern list -> Parsetree.pattern
val construct : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.lid -> Parsetree.pattern option -> Parsetree.pattern
val variant : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Asttypes.label -> Parsetree.pattern option -> Parsetree.pattern
val record : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> (Ast_helper.lid * Parsetree.pattern) list -> Asttypes.closed_flag -> Parsetree.pattern
val array : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern list -> Parsetree.pattern
val or_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern -> Parsetree.pattern -> Parsetree.pattern
val constraint_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern -> Parsetree.core_type -> Parsetree.pattern
val type_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.lid -> Parsetree.pattern
val lazy_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern -> Parsetree.pattern
val unpack : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.str -> Parsetree.pattern
val exception_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.pattern -> Parsetree.pattern
val extension : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.extension -> Parsetree.pattern