# How to declare math delimiter pair without wasting math font?

The command \DeclareMathDelimiter allows to define a delimiter which scales nicely with \left, \big etc. Now the problem I have is that I want to use a particular such delimiter from a different font, in my case the \llbracket and \rrbracket from the stmaryrd package. So the code for doing that would be

\DeclareMathDelimiter{\llbracket}{\mathopen}{stmry}{"4A}{stmry}{"71}

However, this requires the math font stmry which will occupy one of the precious 16 math alphabets as soon as one actually uses the command.

Since I don't need any other symbols from that font, I would like to avoid that. I managed to access a single glyph from other fonts as described e.g. in the answers to

grabbing a single Greek glyph from an alternative font in math mode?

but it is not clear to me how one can do that to get the above delimiter feature. Ultimately, I want to use the left & right version in combination with the \DeclarePairedDelimiter command from mathtools.

• short answer, basically you can't. You need to use the math fams for delimiters, you can arrange that alphabets come from text fonts if you are running short of math families. – David Carlisle Oct 30 '18 at 12:45
• @David Carlisle Thanks a lot, even though I of course expected some other answer :) I will try to find some other workaround. – Stefan Waldmann Nov 5 '18 at 12:53