Programmers often take awk "as is", never thinking to use it as a lab in which
we can explore other language extensions. This is of course, only one way to treat
the Awk code base.
An alternate approach is to treat the Awk code base as a reusable library
of parsers, regular expression engines, etc etc and to make modifications
to the lanugage. This second approach was take by David Ladd and J. Christopher
Raming in their A* system.
They write:
While there are a number of systems that will help one construct full-blown metaprograms such as compilers and interpreters, we wanted something with extremely low overhead.
We set out to build a something with the property that it would
help even inexperienced users build simple meta-programs in a
matter of minutes with a few lines of code. A* is the result; it
is more than anything else an engineering exercise, as most of
its ideas are not new. It is the arrangement of these ideas and
the purpose to which they are directed distinguish A* from
other tools.
A* is an experimental language designed to facilitate
the creation of language-processing tools. It is analogous either to
an interpreted yacc with Awk as its statement language, or to a
version of Awk which processes programs rather than records.
A* offers two principal advantages over the combination of lex,
yacc, and C:
a high-level interpreted base language
built-in
parse tree construction.
A* programmers are thus able to accomplish many useful tasks with little code.
