Earley chart parsing
For a finite CFG, chart Iⱼ stores dotted productions [A→β·γ,k], where k is the starting position.
Key knowledge
For a finite CFG, chart Iⱼ stores dotted productions [A→β·γ,k], where k is the starting position. Predict every production of the next nonterminal, scan matching terminals, and complete finished nonterminals into waiting items at their start positions. Close prediction/completion under repeated application. Accept length-n input iff [S′→S·,0]∈Iₙ.
Conditions and scope
- Use a fresh start S′, de-duplicate items and saturate each chart, including epsilon completions.
- For a fixed grammar, careful chart implementation runs in O(n³); a naive exhaustive parse-tree search lacks this bound.
Sources · 1
References
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Evidence and review
Cornell CS4120 Earley section: item definition, initialization, scan/predict/complete rules, epsilon handling and cubic bound.
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Entry details
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- university-core.1
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- University core expansion