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SLR Parsing

Problem: Some states contain shift and reduce itemize.
Example:
$\begin{program} S~=~E~\$. \\ E~=~T~''+''~E~$\vert$~T. \\ T~=~''x''.\end{program}$
LR(0) state construction gives a state containing the itemize
$\begin{program}[E~=~T~\_~''+''~~E] \ \/[E~=~T~\_]~\end{program}$
If we see "+" as the next input token should we shift or reduce?
Solution: Reduce only if the symbol is in follow(E).
The resulting parser is called simple LR or SLR .
The number of states is the same as in LR(0).

Christoph Zenger
4/6/2000