Xah Lee wrote: > in March, i posted a essay "What is Expressiveness in a Computer > Language", archived at: > http://xahlee.org/perl-python/what_is_expresiveness.html > > I was informed then that there is a academic paper written on this > subject. > > On the Expressive Power of Programming Languages, by Matthias > Felleisen, 1990. > http://www.ccs.neu.edu/home/cobbe/pl-seminar-jr/notes/2003-sep-26/expressive-slides.pdf > > Has anyone read this paper? And, would anyone be interested in giving a > summary?
The gist of the paper is this: Some computer languages seem to be `more expressive' than others. But anything that can be computed in one Turing complete language can be computed in any other Turing complete language. Clearly the notion of expressiveness isn't concerned with ultimately computing the answer. Felleisen's paper puts forth a formal definition of expressiveness in terms of semantic equivilances of small, local constructs. In his definition, wholescale program transformation is disallowed so you cannot appeal to Turing completeness to claim program equivalence. Expressiveness isn't necessarily a good thing. For instance, in C, you can express the addresses of variables by using pointers. You cannot express the same thing in Java, and most people consider this to be a good idea. -- http://mail.python.org/mailman/listinfo/python-list
