🚀 go-pugleaf

In article <44600003@hcx2>, dougs@hcx2.SSD.HARRIS.COM writes:
> is either too exhaustive to be useful or just simply beyond a CFL.  Hey, if
> a context-free grammer can't recognize the regular expression
> 
>               x  y  z  y  x     (note: this requires a pushdown machine with
> 	     a  b  c  b  a             multiple stacks, more power than an 
> 				       automata equivalent to a CFL can be)
> 


1.  the expression above is not regular
2.  the expression above is easily expressed as a CFG:

     A -> B
     A -> a A a
     B -> C
     B -> b B b
     C ->
     C -> C c

3.  two stacks suffice for most recognition problems
4.  grammer [sic] is misspelled
5.  automata is plural
6.  why is everybody picking on this guy so much?  All he asked
    for was a CFG for English.  If I asked for a CFG for Pascal,
    would you hassle me about all the Pascal constructs that aren't
    context-free?
7.  The UNIX command "style" contains a yacc grammar for English.
    A paper is included in the supplementary UNIX documentation
    describing "style", but the source is not supplied with the
    BSD distribution.
-- 
Gordon V. Cormack     CS Dept, University of Waterloo, Canada N2L 3G1
                      gvcormack@waterloo  { .CSNET or .CDN or .EDU }
                      gvcormack@uwaterloo.CA
                      gvcormack@water         { UUCP or BITNET }