Page "Bi-directional text" Paragraph 8

In Unicode encoding, all non-punctuation characters are stored in writing order.

This means that the writing direction of characters is stored within the characters.

If this is the case, the character is called " strong ".

Punctuation characters however, can appear in both LTR and RTL scripts.

They are called " weak " characters because they do not contain any directional information.

So it is up to the software to decide in which direction these " weak " characters will be placed.

Sometimes ( in mixed-directions text ) this leads to display errors, caused by the BiDi-algorithm that runs through the text and identifies LTR and RTL strong characters and assigns a direction to weak characters, according to the algorithm's rules.