One language or many
Lynn H. Maxson
Sat, 24 Jun 2000 12:43:59 -0700 (PDT)
Kyle Lahnakoski wrote: " It is
better to see the HLL as a set of domain specific
languages." and "Furthermore I believe you are
saying that a hardware specification language is a
subset of HLL.".
We had best agree to disagree on this point. I
propose only a single specification language that
covers the entire gamut or domain of software
activities. This misnomer between a specification
language and a programming language is one we need
to examine to make clear (or clearer) the
distinction. It began with Iversons APL (A
Programming Language), intended as a specification
language (written only, not executable) to replace
flowcharting, and continued with Prolog to make a
specification language "behave" as a programming
In my system all programming is done by the tool,
the Developer's Assistant, based upon an input set
of specifications. That it works for a
specification language I can refer to two computer
architectures encoded in APL, the earlier Stretch
7080 (in 1962) and the more remarkable S/360 (in
Moreover if you refer to the Intel reference
manuals on its processors, more recently the
Pentium family of processors, you will find a
HLL-encoded "specification" of every instruction.
As you can see it is not new as it has a nearly 40
At one time within Burroughs was a proposal to make
APL the "standard specification" language for all
software and hardware. One language which covered
the hardware and software domains from the lowest
level (hardware encoded logic) to an unlimited
number of higher levels. Burroughs corporate
management turned it down.
Since that time we have seen the rise of AI and
logic programming, the most prominent remnant of
which is Prolog. As a reference I could suggest
"Simply Logical: Intelligent Reasoning by Example"
by Peter Flach. Though ostensibly a tutorial on
Prolog, it nevertheless serves as one on logic
programming as well.
If we back up a bit, broaden our vision somewhat,
we will see that software development is a process.
It takes as input user requirements, transforming
(translating) them into specifications. That's the
first step within the process (as the requirements
come from outside it). Even the object-oriented
advocates had to precede the programming (which
occurs in the construction stage) with UML.
The point is that something occurs prior to
programming and the use of a programming language.
If you will accept the process of specfication,
analysis, design, construction, and testing, then
the question becomes what is it that you respecify
in the later stages? Why would you ever respecify
anything except as part of the specification stage?
If you do not, if that is the only writing the user
does (write specifications), then you turn the
implications of that writing to the tool, the
assistant, who performs the remaining stages
automatically. That includes automated analysis,
design, construction, and testing all under control
of the chosen set of specifications.
In short there is no (people) programming nor
programming language. The only language
controlling each of the successive stages is the
specification language. The logic engine (or
engines) within the tool provide the implications
of the specifications. They proceed asychronously,
incrementally, and in parallel. At any instance
they reflect (present) the "state" of the system
defined by the specifications.
The language is specified within itself
(self-defining). The tool is specified with the
language. Both the tool, the language, and the
source for both constitute the product received by
the user with absolutely no strings attached to its
use. None of the restrictions of "open source" as
none are necessary to insure (protect) its
So there is only one language and one tool from
which all the remaining "desirables" derive.