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88 lines
3.3 KiB
OCaml
88 lines
3.3 KiB
OCaml
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(*
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copyright (c) 2013, simon cruanes
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all rights reserved.
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redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer. redistributions in binary
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form must reproduce the above copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other materials provided with
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the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*)
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(** {1 Levenshtein distance}
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We take inspiration from
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http://blog.notdot.net/2010/07/Damn-Cool-Algorithms-Levenshtein-Automata
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for the main algorithm and ideas. However some parts are adapted *)
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(** {2 Automaton} *)
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type 'a automaton
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(** Levenshtein automaton for characters of type 'a *)
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val of_array : ?compare:('a -> 'a -> int) -> limit:int -> 'a array -> 'a automaton
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(** Build an automaton from an array, with a maximal distance [limit] *)
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val of_list : ?compare:('a -> 'a -> int) -> limit:int -> 'a list -> 'a automaton
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(** Build an automaton from a list, with a maximal distance [limit] *)
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val of_string : limit:int -> string -> char automaton
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(** Automaton for the special case of strings *)
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val debug_print : out_channel -> char automaton -> unit
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(** Output the automaton on the given channel. Only for string automata. *)
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val match_with : 'a automaton -> 'a array -> bool
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(** [match_with a s] matches the string [s] against [a], and returns
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[true] if the distance from [s] to the word represented by [a] is smaller
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than the limit used to build [a] *)
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val match_with_string : char automaton -> string -> bool
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(** Specialized version of {!match_with} for strings *)
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(** {6 Index for one-to-many matching} *)
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(** Continuation list *)
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type 'a klist =
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[
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| `Nil
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| `Cons of 'a * (unit -> 'a klist)
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]
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module Index : sig
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type ('a, 'b) t
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(** Index that maps 'a strings to values of type 'b. Internally it is
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based on a trie. *)
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val empty : ?compare:('a -> 'a -> int) -> unit -> ('a, 'b) t
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(** Empty index, possibly with a specific comparison function *)
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val add : ('a, 'b) t -> 'a array -> 'b -> ('a, 'b) t
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(** Add a char array to the index. If a value was already present
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for this char it is replaced. *)
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val add_string : (char, 'b) t -> string -> 'b -> (char, 'b) t
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(** Add a string to a char index *)
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val retrieve : limit:int -> ('a, 'b) t -> 'a array -> 'b klist
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(** Lazy list of objects associated to strings close to
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the query string *)
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val retrieve_string : limit:int -> (char,'b) t -> string -> 'b klist
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end
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