Does TLF support Syriac (RtoL) script like Hebrew and Arabic?
Here is what I noticed when I pasted a text in Adobe's text layout demo site for a sample Syriac text. The text is not rendered correctly (what you see is the isolated forms of each character):

The corrected form should look like this (as pasted from MS WORD):

The fonts used are TTF with opentype layout features. Syriac characters, like Arabic, change their shape depending on their contextual position.
what does it take to support Syriac in TLF?
