Case insensitivity in config filesΒΆ

Setting names config files are not case sensitive. This was done to prevent confusion as people would typically miss case settings. For example, in MPF prior to version 0.17, the following would work:


While the following would not:


What happens internally is that all the settings (i.e. the “keys” of the key/value pairs in config files) are converted to lowercase internally. We believe that this should not be a problem and in fact should be transparent to most game programmers. We also have attempted to make sure that all functions that reference objects that are set up in the config files also convert their references to lower case. For example, if you have a coil defined like this:

    number: ...

And then later you refer to it via your code as


That will still work because the device collection object that holds the list of coils will convert the incoming request to lowercase. All that said, there’s one “gotcha” with this. The case insensitivity means that you cannot differentiate between devices bases solely on case differences. For example, in versions of MPF prior to 0.17, it was perfectly valid to define lane lights based on uppercase letters. For example, the three lights that make up “W”, “I”, and “N” lanes could have been defined as lane_Win, lane_wIn, and lane_wiN previously. Starting with MPF 0.17, you’ll have to differentiate them in some other way. (For example, lane_win_w, lane_win_i, and lane_win_n. We believe this change was for the better, but we’re always open to options. If you believe we should change this behavior, please start a discussion in our MPF Development forum.