I think this is what the OP is getting at.  In ruby:

    hard_to_spell_variable = 43

    puts 'run a few statements'
    puts "maybe output the var #{hard_to_spell_variable}"


    hard_to_speel_variable = 'a new value' # oops...

    print "output the new value."
    puts  "  Should == 'a new value': #{hard_to_spell_variable}" # doh!!!

Whereas in perl, under the strict pragma, you get:

    my $hard_to_spell_variable = 43

    # ...

    $hard_to_speel_variable = 'a new value' # perl throws a hissy fit.

This does present problems in other places as well.  I've seen it a
couple of times when people are trying to define DSLs.  You want to
force ruby to dispatch to missing_method, but it won't because it
assumes that you are trying to assign to a new local variable

    my_dsl do
      please_dispatch_method = 'some value'
      # undefined local variable!
    end



--
Lou