Production missing on page 9 of Compiler Construction

"pupeno@pupeno.com" <pupeno@pupeno.com>
Fri, 31 Aug 2007 17:34:57 -0700

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Production missing on page 9 of Compiler Construction pupeno@pupeno.com (pupeno@pupeno.com) (2007-08-31)
Re: Production missing on page 9 of Compiler Construction DrDiettrich1@aol.com (Hans-Peter Diettrich) (2007-09-01)
Re: Production missing on page 9 of Compiler Construction adrian.devries@t-online.de (Adrian Devries) (2007-09-02)
Re: Production missing on page 9 of Compiler Construction torbenm@app-7.diku.dk (2007-09-03)
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From: "pupeno@pupeno.com" <pupeno@pupeno.com>
Newsgroups: comp.compilers
Date: Fri, 31 Aug 2007 17:34:57 -0700
Organization: Compilers Central
Keywords: books, question

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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