Have you read up on the special treatment of the letter Ra in Devanagari conjuncts?

The sequence र् (R with killed vowel) at the beginning of a conjunct is always rendered as the repha form, i.e. the little hook above the last letter of the conjunct. So when you enter the sequence twice you get र्र्, which is the conjunct RR with killed vowel.

When the sequence virama+Ra occurs following another letter in a conjunct, it takes the rakar form, which is either the little hat below the letter as in this case, or a stroke merged with the full form of the letter. So when you enter the sequence three times you get र्र्र्, which is the conjunct RRR with killed vowel. The first R is displayed as the repha, the second R is displayed as a full form, the third R is displayed as the rakar form. The explicit halant (virama) always indicates that the final vowel is killed.

None of these are 'invalid glyphs' (indeed, they're not glyphs per se, but combinations of glyphs) in the writing system, although I believe RRR is probably not found in actual languages. RR may be.

John

Thanks for calling my attention to the treatment of the letter र in conjuncts. I haven't had the time to read this subject yet. The amount of information that I'm processing in the last few days is just mind-boggling.
But after carefully studying the subject presented in Chapter 9 : South Asian Scripts - I published by the Unicode Consortium, I think I finally understood what's going on here. I'll just repeat below the steps I used to achieve the results obtained by the shaping engine, using the rules stated in the referenced
document :

According to the Rule R2 in page 275 of the document we have : र् + र् = र्र् . Now applying rule R8 in page 277 we get :

I had to use the image above, for I couldn't figure out how to print the cincunflex under the dotted circle. BTW, is there a way of printing on this editor a Unicode point, as one does in MS Word, i.e., by typing the Unicode character code followed by Alt + x ?

The final glyph, although not very clear, should stand for र्र्र्, i.e., Shift + 4 applied 3 times.

Do you agree with this approach ?

The dotted circle is U+25CC.

I'm not sure what you mean by asking if I agree with this approach? This is normal Devanagari shaping, according to script rules, but in practice it is very unusual to have even a RR conjunct, let alone RRR. Most commonly, the repha key, i.e. the shift+4 on your keyboard, which inputs Ra + halant, would be followed by another letter.

The dotted circle is U+25CC

Ok, but how do I print this character here ? In MS Word, you just type 25CC followed by Alt + x, and the character pops up in the Word document. Is there something similar in the Typophile editor ?

I'm not sure what you mean by asking if I agree with this approach?

I was just trying to make sure I was on the right track, after reading so much info about the Devanagari script. That's all.

it is very unusual to have even a RR conjunct, let alone RRR. Most commonly, the repha key, i.e. the shift+4 on your keyboard, which inputs Ra + halant, would be followed by another letter.

That was pretty clear .

Thanks for the input.

Just copy and paste the dotted circle from Word, or use the system character map tool.