I recently ran into an issue where I was trying to do the follow:

Code:
#note SERVER evaluates to myhost:port
apache.port=#{ systemProperties['SERVER'].split(":")[0] }
childa.port=#{ ${apache.port} + 1 }
childb.port=#{ ${apache.port} + 2 }
This fails because it ends up evaluating to:

Code:
childa.port=#{ #{ systemProperties['SERVER'].split(":")[0] } + 1 }
which doesn't seem to work because SpEL doesn't seem to support nested SpEL expressions. Has anyone run into this and tried providing a patch?

In the meantime I have created an issue:

https://jira.springsource.org/browse/SPR-9590