Devanāgarī is the writing system that is adapted by various languages like Sanskrit. International Alphabet of Sanskrit Transliteration (IAST) is a transliteration scheme for romanisation of Sanskrit language. IAST makes use of diacritics to represent various characters. On a computer, these are represented using Unicode standard which differs from how the Sanskrit language behaves at a very fundamental level. This results in an issue that is encountered while designing typesetting software for devanāgarī and IAST. We hereby discuss the problems and provide a solution that solves the issue of incompatibilities between various transliteration and encoding schemes. The base implementation that should be used is available at https://github.com/dhruvildave/uast.rs. Another implementation that extends UAST to around $10$ scripts is available at https://github.com/aneri0x4f/uast-cli and https://github.com/dhruvildave/uast .