Question

Please:
in Latin Language When using : f_t this way is meant t and f. F_t If not glyph but as a result of the combination of tow glyphs … Is this true?

And this is also the case with Arabic Font When put teh_meem-ar This means teh + meem -so- teh_meem not glyph -its- teh and meem

Why was encoding the component glyphs in the arabic font ?!

This encoding: no interest in text documents and not in anything else

Will not answer this question only fool who put this coding

One last question:
In Glyphs App can be a way for the program to identify the component Glyphs through the merger of the index glyphs in the mxl file?

This way you will get rid of the Component Glyphs file in the mxl. Arabic Component Glyphs countless here. This is what I found out through my work on it
Mxl file will explode if completed another line!

This has probably to do with backward compatibility applications that didn’t properly support unicode. The same problem is with the .init, .medi and .fina glyphs. They don’t need a unicode as they can be accessed by the OpenType features. I don’t understand the question.

Yes, Unicode has a lot of legacy encodings that are there for backwards compatibility. Usually, Unicode values above F000 (like some ligatures and the positional forms) mean that they fall into this category.

That only means that the user of the font is not supposed to type them. But it does not hurt to put the codes into the font.

Not quite. f_t is a glyph. It represents two characters. Please read http://www.glyphsapp.com/tutorials/unicode for further information and a few handy tips on this topic. For ligatures, that should already be the case. And you can define components in for a glyph in the XML, yes. You can read all about it on http://www.glyphsapp.com/tutorials/roll-your-own-glyph-data Or do you mean something else? Can you give an example?

Is it possible that the process is done without the need for the inclusion of composite Glyphs in file mxl?

Yes. This should be possible. I will have a look at it.