package confero

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Module ConferoSource

Collation Element Mappings

Sourcemodule Collation_mapping : sig ... end
Sourceval register_collation_mapping : ?lang:Iso639.Lang.t -> Collation_mapping.t -> unit

register_collation_mapping ~lang m registers m to be used for collating string representing text in the language lang.

register_collation_mapping m registers m to be used as a fall-back mapping when collate is called without an explicit mapping and either the language is unspecified or not mapping has been registered for the specified language. A good fall-back is provided by linking against the confero.ducet sublibrary.

This function updates global state and should only be used during program initialization by libraries providing collation mappings or by the main entry point of the application.

Sourceval infer_collation_mapping : ?lang:Iso639.Lang.t -> ?mapping:Collation_mapping.t -> unit -> Collation_mapping.t

infer_collation_mapping ?lang ?mapping () returns the mapping which would have been used by collate given the same named arguments.

Collation Algorithm

Sourcemodule Collation_element : sig ... end

Vectors of weights derived from an input string and a collation element mapping.

Sourcemodule Sort_key : sig ... end

A compact representations of a collation elements as private strings whose lexicographic byte order represent the collation order.

Collation

Sourceval collate : ?encoding:Uutf.encoding -> ?lang:Iso639.Lang.t -> ?mapping:Collation_mapping.t -> ?total:bool -> string -> string -> int

collate ?encoding ?lang ?mapping s1 s2 returns a negative integer, zero, or a positive integer when s1 is ordered before s2, s1 and s2 are unordered, or s1 is ordered after s2, respectively, according to a collation mapping inferred from mapping and lang as follows:

  • If lang is specified and a mapping has been registered for lang with register_collation_mapping then it is used, else
  • if mapping is specified then it is used, else
  • if a fall-back mapping has been registered with register_collation_mapping then it is used, else
  • a mapping using Unicode code point ordering is used.

Pass ~total:true when a total order is required, e.g. when using it as the implementation of Map.OrderedType.compare or Set.OrderedType.compare.

  • parameter lang

    The language used to infer the collation mappping.

  • parameter mapping

    The default mapping if not inferred from lang.

  • parameter encoding

    The encoding of the strings to compare.

  • parameter total

    Ensure that the implied order is total. This is done by falling back to String.compare if the result from the collation algorithm is zero. The default is false, meaning that zero may be returned for two different input strings due to Unicode normalization or due to a non-injective collation element mapping.