Example
lConsider the grammar with start symbol S:
lS ¨ V + S | V
lV ¨ a | b
| c
lThe parse begins by trying to identify the entire input
string as being in syntactic category
S.
lClearly it must find a V to start.
lTo find a V, it checks to see whether the next symbol is one of
those listed.
lHaving found a V, it checks to see if the next symbol is
+.
lIf so, it recurses, trying to find another S.
lIf not it stops.
lAfter the top call to S returns, it checks to see whether
there are any spurious remaining
characters in the input.
lIf there are, the input is not accepted.
lIf not, the input is accepted.