On Dec 13, 9:26, Mark Crispin wrote: of from use may the That's not wholly true; FORTRAN prior to FORTRAN-90 prohibits recursion but it's a required feature in FORTRAN 90. I don't believe it's actually prohibited in BASIC of the mid-to-late 60's. There were certainly inplementations in the early 70s that allowed it, and it's a feature of the modern standards (both de-facto and ANSI). Recursion was also a (required) feature of ALGOL in 1958, and its successors, as was stack-based evaluation. However, in support of Mark, it's worth noting that the main reason there's no recursion allowed in FORTRAN, and it almost was omitted from the original ALGOL spec, was that it was hard for people to understand how it could be implemented across a variety of architectures. Stacks had been around since the mid-50s but lots of machines provided no specific support for them. -- Pete Peter Turnbull Network Manager University of York