Example

Consider the following syntactic definition.

EXAMple $<$string$>$ { $<$example-statement$>$ } END

$<$example-statement$>$:==

CHARge=$<$real$>$

EXCLude=( { $<$atom$>$ } )

MASS=$<$real$>$

TESTing=A1 $\vert$ A2 $\vert$ A3

TYPE=$<$type$>$

$<$string$>$:==

any sequence of four characters.

The following input lines are possibilities for valid constructs:

example A type=ABCD  mass=30.0 end
example B type=BBBB  charge=5.0  exclude=( A B C D ) end
example C charge=5. mass=40.0  type=XXX   testing=A3 end
example D end