It would be very helpful to have a “framework” to help and accelerate the development of custom TPL. Im a quite new to TPL development, perhaps there are some nifty tricks around I am not aware of, but I find creating a new pattern module from scratch is quite tedious. I would like to compare this to developing regexes. When you have a complex regex, you first want to make sure it does exactly what you want, so you use pcretest to thoroughly test it. At this point you are reasonably confident that it’s ok. For TPL modules, for starters, a syntax checker would be very helpful, at least for the beginner. Right now, when you upload your new TPL, it stops at the first error and does not always provide a useful error message. So a syntax checker giving helpful messages for multiple syntax errors would be a huge boon. Then one could start daydreaming of a checker beyond simple syntax. Eg. say that this particular thingie is not possible in the context your are using it.
I am aware that up to a certain point you can get away with CAM, but if you have more specific use cases, then you need to dive into TPL.