On a customer name field, we wish to handle user input in incorrect case. So &q

Other than writing code that strip spl characters and put them back in after changing the case, the straight-forward way to handle this is to not use special characters in the name. Given that this is a name, a hyphen-versus-a space should be "visibly" the same. However, if you want them differentiated, you can use an additional column to store the data with special character and a normalized one (i.e. you can use strip() function to remove spl characters) and store this to search the data against. But be advised that 99.9% of your names may not have these special character and you will be including additional overhead by adding a new column. A reverse-index in a 'search' engine uses the above method to make a search result more effective. However you need to weigh the benefits against cost of development and maintenance.
Talking about writing code, you can write a simple plug-in expression function that'd do what you are looking for (and share it in Appian forum for others to benefit from as well)

If the only special case you are worried about is hyphen, you can write a reasonably simple rule to handle it. I called this convertToProper with a Text input called txt.

=if(search("-",ri!txt)=0,proper(ri!txt),
substitute(proper(substitute(ri!txt,"-"," "))," ","-"))

Thanks Elizabeth, I've taken your rule (with credit)

Something to look-out for:- With the above rule, if your text contains a genuine space and a hyphen, for e.g. "joe-mc donald", then the output will become "Joe-Mc-Donald" where the other spaces will be replaced by hyphen.