Everyone,


 Well I decided to take dans advice and do a simple
forth like implementation. Overall it doesn't seem
like its going to be difficult at all. I have run into
a small snag. As a side note I have already decided
that this is note possible, this is just a last ditch
to see if there is a solution. 

 It has to do with the type system more then anything
else. I use a stack to handle data that the
interpreted process is manipulating. I provide a
specific set of words that this forth like language
will use to manipulate the stack. Of course, stacks
may only be of a single type 'a. So if declare a new
type to be

 type some_type = Int of int | Float of float | Word
of string 

Them my stack is some_type Stack.t 

 Ok this is all fine and dandy, until a few months
from now when I want to add a new type say File of
Unix.file_descr. The word implementations to support
the new type wouldn't actually be a problem. However,
extending the type seems to be impossible.

 The only way I can see to do this at the moment is to
modify the type and recompile the whole system. That
or come up with some type of indirect identifier
piece, but I would rather not do that. I played around
with polymorphic variants but that doesn't seem to buy
my anything here.

  Of course, since this is the first non-toy language
I have implemented I may be mifundamentalhing
fundimental.

Please forgive (and hopefully correct) any ignorance 
I am displaying here.

Thanks,
Eric

--- Dan Andersson <rhq093s@tninet.se> wrote:
> Forth languages are almost trivial to implement.
> 
> /Dan Andersson
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