Atomic expression?

[Francisco Vila]

I'm sorry, cannot find an earlier message where Mr. percival asked if "e'1" is 
an expression. He was aswered yes, just as "1" is a (minimal) math 
expression.

IMO this is not so easy. [Numerical or symbolical] math expressions can 
substitute another expressions as long as sintaxis allows it. But, can e'1 
without curly braces substitute a true expression as { e'1 } ?

It would be fine if the sintax diagrams of the LP input language were easily 
available. I remember that Pascal lenguage tutorials were completely 
based in these diagrams. This would be too much for someone, but always served 
as a reference.

-- 
Francisco Vila Doncel. Badajoz (Spain)
http://www.paconet.org