Can I do "string contains" in a WiX if statement?

Question

Can I do the following and see if the configuration contains the word "Extra":

<?if $(var.MyProject.Configuration) >< "Extra" ?>

This link suggests I can use >< but it doesn't work for me. It compiles with this error:

error CNDL0162: An illegal number was found in the expression

Answer 1

Short answer: not without writing a preprocessor extension.

The link you provided discusses MSI expressions. The WiX preprocessor is slightly different and doesn't have the substring operators (or bitwise numeric operators for that matter).