The *.t files make a program  main.t and main.x
which is an interpreter for a little functional language.
Some functional programs are in *.fp.

They can be run on Sol0 as in:   main.x <primes.fp

The Syntax of the functional Language:

program ::= exp

exp ::= ident | numeral | nil | ( exp ) |
        unopr exp | exp binopr exp |           usual operator priorities
        if exp then exp else exp |             conditional
        exp exp |                              application
        lambda ident . exp |                   abstraction
        let [rec] decs in exp                  local declarations, block

dec  ::= ident = exp
decs ::= dec,decs | dec

unopr  ::= - | hd | tl | null
binopr ::= + | - | * | / | = | ::