Print an arbitrary variable from a Portfile interpreter

mportkey.tcl

#! /usr/bin/env port-tclsh
# usage: mportkey.tcl varname portname [variants]
lassign $argv varname portname variants
package require macports
mportinit
lassign [mportlookup $portname] portname portinfo
set variations [macports::_variants_to_variations $variants]
set mport [mportopen [dict get $portinfo porturl] [dict create subport $portname] $variations]
puts [_mportkey $mport $varname]