Dictionary Services

Though widely usurped of their ‘go-to reference’ status by the Internet, dictionaries and word lists serve an important role behind the scenes for features ranging from spell check, grammar check, and auto-correct to auto-summarization and semantic analysis. So, for your reference, here’s a look at the ways and means by which computers give meaning to the world through words, in Unix, macOS, and iOS.

→ nshipster.com/dictionary-services/

The article explores dictionary-related APIs in Swift across Unix, macOS, and iOS, highlighting their role in features like spell check and semantic analysis.

On Unix, macOS provides a word list at /usr/share/dict/words with 235,886 entries, useful for tasks like generating pass-phrases, but limited by its monolingual nature. macOS enhances this with /Library/Dictionaries, offering multilingual dictionaries (e.g., English, Chinese, Japanese) in .dictionary bundles containing binary data, CSS, and images.

The Core Services framework’s DCSCopyTextDefinition function retrieves definitions, defaulting to all active dictionaries, with private APIs like DCSCopyAvailableDictionaries enabling specific dictionary access and HTML output, though these are not App Store-compliant.

On iOS, UIReferenceLibraryViewController provides a modal interface for definitions, initialised with a term and checked via dictionaryHasDefinitionForTerm:, leveraging Swift’s interoperability with Core Foundation for robust text processing.

These APIs, despite some proprietary limitations, enable developers to integrate advanced linguistic functionality into apps, enhancing user experiences with minimal code.