Fact · Languages and accents
Unicode's bidirectional algorithm changes a European number to an Arabic number when the nearest strong character before it is an Arabic letter.
Checked against its source on October 17, 2026
In the source's own words
“If an AL is found, change the type of the European number to Arabic number.”
Unicode Standard Annex #9: Unicode Bidirectional Algorithm, Unicode Consortium, Unicode Consortium, 2026, Rule W2 (weak types).
Open the original- What it measures
- Rule W2 searches backward from a European number (a Western digit) until it finds a strong character. This is the rule that assigns the digit's direction in Arabic text, which affects how it lines up with neighboring punctuation.
- What it does not show
- The rule governs the order of characters in the display, not the shape of the digits. The standard is for Unicode 18.0.0 (revision 52), as read on 2026-10-17.