loading checksums table from pre-checksum block?

[René J . V . Bertin]

Hi,

I have a port with lots of subports for which I keep the checksums in a 
table-like structure in a dedicated file, so as to keep the Portfile a bit more 
manageable (and to be able to generate said table with a script when it's 
upgrade time).

Currently I have an explicit check that tests if the file exists in $filespath 
before sourcing it, to prevent errors when run from the registry.
Doing it from a pre-checksum block would be more elegant and more efficient, 
but I cannot seem to figure out how to get the `source` command to apply to the 
correct context. 

How should I do that? I tried versions of the below with and without the quotes 
or the uplevel, none works:

{{{
pre-checksum {
    ui_debug "Reading checksums from ${filespath}/${checksums.table}"
    uplevel "source ${filespath}/${checksums.table}"
}
}}}

The checksums table file looks like this:

{{{
# checksums for foo family v5.47.0

array set checksumtable {
        # http://download.foo.org/stable/foo/5.47/foo1-5.47.0.tar.xz
        foo1 {
                e3a2f4e62d7ff76ff87479b322f3e8054e8f1dd2
                72a1962de852590d9494ebcfa9f98e1d394bad4680384b9a6937a7082140259e
        }
# many more of those
}
}}}

(the Portfile contains a procedure called from each subport that gets and sets 
the checksums for that subport.)

I could change the include file if needed but I'd prefer not to, unless there's 
a simple way to turn it into a true, pure datafile

Thanks,
R.