Questions on the notation used in the spec

John Cowan cowan at
Mon Oct 22 11:59:54 PDT 2007

Jeff Dyer scripsit:

> Alpha, beta, etc are a short-hand for describing similar productions. They
> can be expanded by replicating the parameterised production for each value
> in the corresponding set. E.g.
>    A(alpha) := B(alpha)
> can be rewritten as:
>    A_allowColon := B_allowColon
>    A_noColon := B_noColon

Yet another partial reinvention of Ad van Wijngaarden's two-level
grammars, I see.  Like most reinventions, it generates only a 
finite number of rules, although in principle there is nothing
to prevent recursion in the metarules (those named with Greek
letters here).

(The below .sig was chosen entirely at random.)

John Cowan  cowan at
In the sciences, we are now uniquely privileged to sit side by side
with the giants on whose shoulders we stand.
        --Gerald Holton

More information about the Es4-discuss mailing list