David, thanks for submitting a revised version of this patch.

JWE asked for some comments in the code.  If you are still interested in this patch, could you submit a version with comments for each of the functions?

Unfortunately, I lost dispatch.h
I didn't realize I hadn't committed it and somehow I managed to delete it.  I'm proposing a bugfix which adds ignored files to .hgignore so this doesn't happen again: https://savannah.gnu.org/patch/index.php?8442

(with this, you can tell what you've changed just by doing 'hg status')

I just rewrote dispatch.h (the cases are adopted from the old find-function.  Any cases that are missing were missing in the original find-function)

Here's the patch again (with it this time)

(file #31250)

While working on the "find" function, I was annoyed by the large "if-else-if" list of conditionals which all do exactly the same thing (check if the input matrix is a particular type and then call the "real" find function with the proper template type).  I had to go down the list of calls and add a fourth parameter to each and every one.  There should be utility "dispatcher" functions which take a functor template template and an octave_value_list of arguments and call the functor with the proper template argument.  Then calls such as the long conditional statement in "find" can be consolidated into one place rather than having to have them for every single function which can take multiple types.  And if a function call needs to be changed, it only needs to be changed in one place.

I've attached an example for how to do this with find (this also includes my changes from https://savannah.gnu.org/patch/?8386 sans the fourth parameter).  Now any other function which takes the same matrix types as "find" as an argument can call the same "dispatch_all" function to call the functor with the proper template argument.

For functions which take multiple arguments with variable types, this can be done by nesting the functors (kind of like currying.  If you'd like I can give an example).