🚀 go-pugleaf

>Joseph Allen:
>   No, it can be done!  Really!  Just don't allow loops, gotos or
>   recursion.  Now who wants to write a compiler in a language with
>   these restrictions?

In article <ROCKWELL.91May14081634@socrates.umd.edu> rockwell@socrates.umd.edu
(Raul Rockwell) writes:
>Well, you can allow loops as long as they can guaranteed to be
>bounded. ...
>
>I suppose such a thing could be quite instructive.  Ask the question
>"how useful is this language when I remove everything which
>potentially prevents halting?".

Languages without loops can indeed be useful.  One such example is the
interpreter inside BPF, the Berkeley Packet Filter.  The `language' is
in effect an accumulator machine with packet-memory operations and a
small auxiliary memory.  The compiler takes packet matching
specifications (`tcp port 25') and emits load-and-compare operations to
decide whether the packet should be copied.  The interpreter allows
only forward branches and has no call instruction, so it is not possible
to create a loop.

BPF is very useful in its particular problem domain.  It is not much
good as a general purpose programming language. :-)
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 415 486 5427)
Berkeley, CA		Domain:	torek@ee.lbl.gov