Production missing on page 9 of Compiler Construction

Hello,


I'm reading Compiler Construction, by Niklaus Wirth, available on
http://www.oberon.ethz.ch/WirthPubl/CBEAll.pdf and on page 9 he shows
this little piece of BNF:


E = T | A "+" T.
T = F | T "*" F.
F = V | "(" E ")".
V = "a" | "b" | "c" | "d".


A is being used on the right hand side without it being defined on the
left hand side first. What am I missing?


The only thing I can think of is that it is missing a production at
first, like:


A = E


>From this BNF it writes this "programs" (on page 10):


a*b+c
a+b*c
(a+b)*(c+d)


Thanks.

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