Converting `fend` scripts to `bc`/`dc` syntax for portable scripts

[Alhadis]

Not sure how doable this would be, but it'd be nice to have some way of converting a fend script to bc or dc syntax (chiefly for embedding within a portable shell-script designed to run on systems that don't have fend installed).

[printfn]

I haven't actually used bc/dc before, but this definitely sounds like it'd be a cool and useful feature to have.

[Alhadis]

I recommend starting with bc, as its syntax is the easiest to learn and use in everyday practice. dc uses Reverse Polish Notation and is a concatenative stack-based programming language that's literally older than C (it's one of the oldest surviving Unix commands, IIRC). bc can even compile to dc syntax, so the former is probably worth targeting first.