&reftitle.constants; The following constants define the normalization form used by the normalizer: Normalizer::FORM_C (string) Normalization Form C (NFC) - Canonical Decomposition followed by Canonical Composition Normalizer::FORM_D (string) Normalization Form D (NFD) - Canonical Decomposition Normalizer::FORM_KC (string) Normalization Form KC (NFKC) - Compatibility Decomposition, followed by Canonical Composition Normalizer::FORM_KD (string) Normalization Form KD (NFKD) - Compatibility Decomposition Normalizer::NONE (string) No decomposition/composition Normalizer::OPTION_DEFAULT (string) Default normalization options