I think it is a bad idea as well. What happens if FOO='$BAR' and BAR='$FOO', f.ex? How do you include a literal $ character in the value of a variable without breaking anything? There are just too many unpredictables. If there's only a single level of replacement, none of these things becomes an issue. Of course, indirection becomes impossible, but that should be implemented properly at the top level, with a well-defined syntax; at that point you are on your way to a full-fledged templating system or even a complete language.