Re: general-purpose vs domain-specific programming languages

["Nick Roberts" <Nick.Roberts@dial.pipex.com>]

I've often found there is much mileage in developing very simple
interpreters, which are written in Ada, but which provide a separate
environment and language for doing a very specific job.

The 'environment' is typically line-oriented interaction (about as simple
as it can get); sometimes 'batch' file capability needs to be added (also
very simple: just read a named text file instead of current input).

As long as the syntax is kept very simple (cf. the 'ed' of UNIX), the
interpreter is easy to maintain, yet provides the thing it most needs to:
convenience. It is likely to be less convenient to have to write and
compile an Ada program to do something that would be a one-liner for such
an interpreter.

The biggest drawback tends to be psychological: persuading people to learn
the new syntax. Programmers seem to have a pathological neophobia when it
comes to this sort of thing!

-- 

Nick Roberts
Croydon, UK

Proprietor, ThoughtWing Software; Independent Software Development
Consultant
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