LR(0) Parsing:

Left-right, lookahead 0.

We have an automaton that tracks our progress through the productiion rules, and
the transition arrows are the top symbol on the stack.

Recall that a reudction on the stack needs to use the top symbol! This weakens the grammars
recognized.

How to build the automaton:

1) Start at  . S
2) Add the closure of . S to your state
3) add transitions based on the top symbol of the stack
4) Take the closure
5) repeat...

(only a finite number of states/edges, so this algorithm eventually terminates)

The automaton keeps both a working symbols (terminals & non-terminals) stack
and a "computation history" stack, so we know where to return to when we perform a reduction.
When we perform a reduction, we pop the first few symbols off the working stack, replace them
by the reduction rule at the top of the stack, and go back one step in the computation.

Every state must either have shift rules, or one reduction rule, but not both.]

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LR Conflicts/

A shift/reduce conflict is when a state has both a shift rule and a reduce rule
(it is unclear which to take)

A reduce/reduce conflict is when there are multiple ways to reduce the top elements of the stack.

LR(0) parsers don't provide a facility for performing such a reduction.

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SLR(1) Parsing:

Transitions are based on lookahead token instead of top of stack