Hi,

Thank you very much! In fact, you can simplify further: the Alt+R before | is not necessary. This is due to the machinery of TeXmacs to detect automatically pair of delimiters.

Best,
Frank

On 2/26/21, Basile Audoly wrote:
> Hi Frank,
> another option is to type "^L . q ^R |" in math mode
> ^L . creates a pair of invisible brackets
> ^R | replaces the invisible closing bracket with a (closing) vertical bar.
> with macOS look and feel, ^ = option
> Basile
>
>> Le 25 févr. 2021 à 20:13, Frank <address@hidden> a écrit :
>>
>> Hi,
>>
>> I wonder what is the correct way to do that? For the moment, I only know that I can write the thing in the absolute value then delete the first delimiter, which is a bit more difficult since I need to move the cursor back and forth.
>>
>> Best wishes,
>> Frank
>>
>> On 2/24/21, Basile Audoly wrote:
>>> Hi Frank,
>>> I use a right-hand-side-only delimiter for this purpose.
>>> (math (concat (around* "<nobracket>" "q" "|") (rsub "C") "=y"))
>>> Basile
>>>> Le 24 févr. 2021 à 10:42, Frank <address@hidden <mailto:address@hidden>> a écrit :
>>>>
>>>> Dear all,
>>>>
>>>> I wonder how to input the symbol for restriction of function? Now I input, say,
>>>>
>>>> (math (concat "q|" (rsub "C") "=y"))
>>>>
>>>> which will generate, in my opinion, an incorrect spacing (see the space before and after "="). I also suspect that this is semantically incorrect.
>>>>
>>>> Best wishes,
>>>> Frank
>