config object - interp dispatch pattern

# warning - copy/pasted from parts of a working system, but not tested, so probably buggy as written

oo::class create ConfigInterp {
    variable interp

    variable state  ;# context for the current token
    variable world  ;# the config object that is being created

    constructor {script} {
        set interp [interp create -safe]
        $interp alias unknown [self]
        set state(section) ""
        my eval $script
    }
    method get args {
        array get world {*}$args
    }
    method eval {script} {
        $interp eval $script
    }
    method unknown {args} {
        puts "Unknown: [regexp -inline -line {.{0,40}} [join $args " "]]"
    }
    
  # these are to be used in the config script:

    method version {str} {
        set world(version) $str
    }

    method section {name script} {
        set oldsec $state(section)
        lappend state(section) $name
        try {
            $interp eval $script
        } finally {
            set state(section) oldsec
        }
    }
}

# Usage is something like:

puts [open config.tcl w] {
  version "Testing"
  section foo {
    section bar {}
    section baz {}
  }
}

set ci [ConfigInterp create]
$ci eval [readfile config.tcl] ;# eg
array set config [$ci get]