search

w3c / alreq

Documenting gaps and requirements for support of Arabic and Persian on the Web and in eBooks.
Other
62 stars 31 forks source link

Numerical Fractions #59

Open shervinafshar opened 8 years ago

shervinafshar commented 8 years ago

A discussion happened on Unicode mailing list regarding properties of presenting numerical fraction in Arabic script. Although the W3C TR on math has some text on this topic, but it would be useful to cover it somewhere in ALReq.

duerst commented 8 years ago

@shervinafshar: Thanks for picking this up.

ntounsi commented 7 years ago

The oblique bar / is used in many context, e.g. fraction or report symbol etc., to have the same meaning as in Latin script. Mirroring it to \ does not seem evident.

One can find the oblique sign in :

However, writing order may vary with Arabic digits : 90/13 instead of the above (13/90).

A wiki page is being drafted on this topic. https://github.com/w3c/alreq/wiki/Arabic-numerals-(Draft)

khaledhosny commented 7 years ago

I used to think that not mirroring the fraction slash was a limitation of computer typesetting, but then I found example of old school math books (circa 1930) and it was using un-mirrored fraction slash, so it seems to me not mirroring it is probably as old as modern Arabic math typesetting.

ntounsi commented 7 years ago

Discussion is related to Section on Numbers #101

Here are some pictures on Arabic fractions (excerpt from a recent book about an ancient work on Arabic mathematics).

20170717_224527 1525 and 1/2 (a half)

20170717_225025 the result of the operation 28022/7 = 4003.14 4003 and 1/7 (one seventh)

20170717_230453 on top : 3 and 4/5 (three and four fifth, 3 + 4/5) bellow : 4/5 3 (four fifth of three, 3*4/5 )

20170717_224948 3/4 5 and 1/3 (three fouth of five and one third, 3/4*5 + 1/3)

gounaman commented 3 years ago

Sometimes the horizontal line can be tilted, as a stylization