From fff7424a9c2dcde1f5aff66e75a62bd7112f32c6 Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Wed, 23 Mar 2022 10:37:02 +0200 Subject: Add note on disfig.* variables idea --- libbuild2/config/init.cxx | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'libbuild2') diff --git a/libbuild2/config/init.cxx b/libbuild2/config/init.cxx index e92db4c..0472cfd 100644 --- a/libbuild2/config/init.cxx +++ b/libbuild2/config/init.cxx @@ -257,6 +257,22 @@ namespace build2 // Note that this variable is not saved in config.build and is expected // to always be specified as a command line override. // + // We also had the idea of using NULL values as a more natural way to + // undefine a configuration variable, which would only work for non- + // nullable variables (such as project configuration variables) or for + // those where NULL is the default value (most of the others). However, + // this cannot work in our model since we cannot reset a NULL override + // to a default value. So setting the variable itself to some special + // value does not seem to be an option and we have to convey this in + // some other way, such as in config.config.disfigure. Another idea is + // to invent a parallel set of variables, such as disfig.*, that can be + // used for that (though they would still have to be specified with some + // dummy value, for example disfig.hello.fancy=). On the other hand, + // this desire to disfigure individual variables does not seem to be + // very common (we lived without it for years without noticing). So + // it's not clear we need to do something like disfig.* which has a + // wiff of hack to it. + // auto& c_d (vp.insert ("config.config.disfigure", true /*ovr*/)); // Hermetic configurations. -- cgit v1.1