U++

It is sometimes useful to specify things in config based on current environment, e.g. paths can contain $HOME variable to make default config usable for all users.

Enclosed patch allows replacing such variables by their values. To keep things backwards compatible, this feature must be enabled explicitly by '@replace-env' in the config file. It can be also turned of again with @ignore-env. This allows to use this for only specific parts of configuration. When in the replacing mode, "$$" can be used to escape literal "$".

Example:

test1=$HOME/test1
@replace-env
test2=$HOME/test2
test3=text containing $$
@ignore-env
test4=$HOME/test3

Config::test1 = $HOME/test1
Config::test2 = /home/h/test2
Config::test3 = text containing $
Config::test4 = $HOME/test3