Regarding the input and output of Unicode combining diacritics

I am a linguist and I am trying to use a combing diacritic ‘Combing Minus Sign Below’ (U+0320) in LaTeX and Word; for instance, by typing the letter ‘a’ and the mark one gets ‘a̠’. However, in TeXmacs this character combination is unexpectedly presented linearly:


The font I chose supports the correct visual presentation and therefore it cannot be blamed.

This problem is presumably firstly reported by another user about a year ago (, who correctly ascribes the symptom to the character-rendering mechanism of TeXmacs, yet there seems to be no further feedback. Some of the user’s expressions may be too professional, which I shall illustrate a bit.

The converting mechanism in TeXmacs seems to render certain character sequences into a single character that is visually indistinguishable from that sequence, if the character is pre-assigned a position in Unicode. For example, if one types the letter ‘a’ and a combining diacritic ‘Combining Ring Above’ (U+030A) in LaTeX or Word, one gets the combined sequence ‘å’ (the letter ‘a’ plus ‘Combining Ring Above’) consisting of two symbols; pasting this sequence into TeXmacs, nevertheless, will convert this string into a single letter ‘å’ (U+00E5) pre-existing in Unicode, an output now undecomposable into its previous form. The ‘a̠’ mentioned above, on the other hand, does not have a corresponding single letter in Unicode and thus remains unchanged in TeXmacs, yet the rendering mechanism wrongfully leaves the diacritic following the vowel instead of in situ.

Here are my questions:

  • Is there a way of preventing the compulsory conversion of certain string sequences into a single ‘precomposed’ letter in TeXmacs?

  • Is there any solution supporting the correct output of combining diacritics?

I’m afraid that TeXmacs does not have a mechanism to handle these combining characters yet. But I might be wrong. The right place to ask these technical questions is the texmacs-dev list. It will also be good, for tracking purposes to file a bug here:

I’ve checked and there is no yet any bug report which address similar issues.

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Thank you very much for the prompt replies, @mgubi and @pireddag. I will see what I can do next.