[TYPES] the possibly uselessness of semantics, was -- The type/object distinction and possible synthesis of OOP and imperative programming languages

Uday S Reddy u.s.reddy at cs.bham.ac.uk
Sat Apr 20 14:58:44 EDT 2013

Matthias Felleisen writes:

> I think if more of us did this kind of work, we would see two
> developments"
> 1. Working programming language developers may figure out that our tools
> are useful and use them.
> 2. We would figure out what kind of tools working language developers
> really need, and we might develop/change tools so that they are useful in
> the real world.

I would happily endorse these ideas.  In fact, this is what I think would
constitute "applied PL research": understanding, evaluating, critiquing, and
shepherding new programming languages, which I believe will necessarily come
from outside our community because it is the application develepors who
understand best where the needs are for new languages.

However, I still see considerable problems because it is not clear to me
what "our tools" are.  Our field has suffered from early fragmentation.
Right in the 60's, people divided themselves in operational, denotational,
and axiomatic camps and these camps have never come together, perhaps only
diverged more in the succeeding decades.  Further fragmentation in the
language styles, e.g., functional programming vs imperative programming,
later, ADTs vs objects, statically typed vs dynamically typed, correctness
by verification vs correctness by construction and so on, ensued.  There is
no core body of knowledge that we all accept as being fundamental and
essential to our field.  No two programming language text books have the
same content, no two programming language courses teach the same material,
and we even have difficulty picking just one of the published text books as
being good enough for our own courses.  As a result, even when we force our
students to take our courses, there is no common base of knowledge that our
graduates share when they go out into the real world and perhaps become PL
designers one day.  Dermot McGahon mentioned just earlier today that he was
not taught "these concepts" during either his Bachelor's or Master's
degrees, which is telling.

I really find it hard to see how we will be able to have any more influence
on the outside world until we are able to put our own house in order.  And,
that means figuring out what our core body of knowledge is, integrating all
the various approaches we have developed over the years, and ironing out our
differences to the point that we see the merits in each other's approaches.

Perhaps there is a useful role that SIGPLAN can play in generating such a


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