Re: Some questions about fractions

[Eric Muller]

Jill Ramonsky wrote: I'm wondering, exactly how equivalent are the following sequences: U+00BC (vulgar fraction one quarter) U+215F U+0034 (fraction numerator one; digit four) U+0031 U+2044 U+0034 (digit one; fraction slash; digit four) In particular, should they be rendered with the same glyph? I would rather phrase the question as “"if all characters involved are supported by a given layout system, should those three sequences produce the same visible result?” The first change is to account for an implementation not supporting, e.g., U+215F. The second change is to allow different glyph organizations, as long as they produce the same ink. That being said, I think the answer is yes, assuming non digits around the last one. Is it possible to compose a single glyph for (say) twenty two over seven, using the fraction slash? Sure. It is ok to have a single glyph for arbitrarily large fragments of text, fractions or not. If a glyph displaying “whole word” is available and appropriate for the circumstances, a rendering engine could use it. If I were to write "one quarter" as U+0031 U+2044 U+0034, how should I then write "one and a quarter"? Is there a "fraction space" which I should use to separate the "1" from the "1/4"? Unicode 4.0 Section 6.2 p 159 has the answer: If the fraction is to be separated from a previous number, then a space can be used, choosing the appropriate width (normal, thin, zero width, and so on). For example 1 + THIN SPACE + 3 + FRACTION SLASH + 4 is displayed as 1¾. Eric.