Howto inspect Portfile variables to debug install

[Chris Gorman]

Hello,

I was wondering how to inspect variables in a port file.  Specifically, I want to apply a patch conditionally if perl is version 5.10.0.  

I'm trying something like 

if { ${configure.perl} eq "/usr/bin/perl" && [vercmp ${perl5.version} 5.10.0] < 0 } {
    patchfiles-append patch-man_Makefile.in.diff
}

in the Portfile. This doesn't work and I would like to inspect configure.perl and perl5.version to see what they are.  Is there any way to do this?  I'm looking for a solution like using printf in c, or echo in a shell script.

Thanks

Chris Gorman