Automated Build Generator

I tried to add the possibility to override the repository default settings in a distribution.
As we discussed elsewhere (I cannot find the issue anymore), using ${next-value|false} didn't work, because false would be interpreted as text and thus would evaluate to true.
Hence, I used the following definitions in commit:39a9a3684cee349ad816d7ed6f60fc0588f9e312:

"false":                            false,
"true":                             true,
"git.wipe-out-workspace?":          "${next-value|${false}}",
"git.clean-before-checkout?":       "${next-value|${true}}",

This works in principle. However, if "next-value" is defined as false, it is nevertheless considered as undefined (NIL?) and the fallback is used.
I guess, you need to distinguish undefined (NIL) and false state, when evaluating next-value expressions.