collators

A collator is a device or software component that collects and arranges items in a specified order. In manufacturing and mailroom contexts, a physical collator gathers loose sheets, forms them into complete sets, and stacks or binds them for finishing such as stapling or binding. Modern collators can handle multiple input sources, differentiate by page number, and feed output to additional finishing equipment. They are used in print shops, offices, and mailrooms to prepare documents, booklets, or catalogs efficiently.

In computing and information processing, a collator refers to a component that defines the rules for comparing and ordering strings or records. Collation governs how characters are treated during sorting, including case, diacritics, punctuation, and locale-specific conventions. Software collators are integral to databases, word processors, and programming languages, providing locale-aware sort operations. For example, in many locales, "a" and "A" are treated as equivalent for primary sorting, while some accents determine secondary or tertiary order, and certain combinations like "ch" or "ll" may have historical weight in specific languages.

Standards and implementations: The Unicode Collation Algorithm specifies a way to compute sort keys for strings across languages. Locales in operating systems and libraries implement collators, such as ICU, Java's Collator, and .NET's CompareInfo. Databases also offer collation support to enable locale-aware ordering in queries. Performance considerations include the preprocessing of sort keys and the handling of conflicting or ill-formed input.

See also: Collation, Sorting, Unicode Collation Algorithm.