On the Specification of the Display of Documents in Multi-lingual Computing

摘要

The first phase of UNU/IIST's MultiScript project comprised a comprehensive study and analysis of multi-lingual documents, on the basis of which a formal model of a generic multi-directional, multilingual document was developed [1, 2, 4] using the RAISE specification language RSL [8]. WE briefly reivew this formal model, then investigate the requirements on the physical properties of the character sets used to display and print multi-directional, multi-lingual documents and extend the model and the formal specification appropriately. This reveals that although the alighnment information contained in the character sets which are currently in common use is perfectly sufficient for displaying and printing documents in which the text is unidirectional, there is typically a shortcoming as far as multi-directional texts are concerned which means that it is impossible to specify the alignment of characters from a horizontal script with characters from a vertical script other than by choosing some arbitrary default or by specifying the alignment on an instnace by instance basis. We propose a simple extension to the alignment information of a character set to alleviate this problem and formally specify its properties.