Caml-list,

I have to write an interpreter for a datatype rich purely applicative
language. I have already written a naive interpreter (like in programming
languages class) and was wondering what where the options for writing
something that would perform better while keeping it maintainable by a
single person < 5% dedicated and preferably only in core-ML (no C code or
fancy ML extensions).

The language could be described as a rich datastructure typed SQL with a
programming language syntax
- first class sets, arrays, dictionaries, lists and their corresponding
comprehensions
- tuples and records merged into a single concept (accessible per position
like in (x, y) = ... or per label like in for t in tupleSet if t.label == 3
then)
- only applicative functions (no lambda operator, no partial application)
- simple types are int, double and string
- only user declared types are tuples-records

It is mainly used for data transformation : take a list of countries,
extract from an database the international airports of those countries,
geolocalize them using city/location table, generate a distance table using
a great-circle distance, assign to each size of plane the legs they can do
based on their maximum fight range, etc.

The language has a JavaScript inline capability

    execute JavaScript {
        //write your javascript code here
    }

that's typically used to define functions, unroll comprehensions to make
them more efficient and to call external libraries (JavaScript has full
visibility on all the language objects and can read/write directly inside,
probably the existing interpreter was written in JavaScript), so I am
considering allowing those features in the core language and only supporting
a very slow JavaScript deprecated compatibility mode.


         Diego Olivier