The influence of productions on derivations and parsing (Extended Abstract)

摘要

The concept of grammar forms [4,5] provides evidence that there seems to be no way to base the definitions of many grammar types used in parsing and compiling solely on the concept of productions.

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Strict interpretations, as introduced in [3,5], of unambiguous or LR(k) grammar forms generate unambiguous or LR(k) languages, respectively. This is not true in the LL(k) case.

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It is decidable whether a strict interpretation of an unambiguous grammar form is unambiguous. For any two compatible strict interpretations G1 and G2 of an unambiguous grammar form it is decidable whether L(G1)@@@@L(G2), L(G1)@@@@L(G2)&equil;&thgr;, finite, or infinite.

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For every grammar form F1 there exists a grammar form F2 such that the grammatical family of F1 under unrestricted interpretations is equal to the grammatical family of F2 under strict interpretations.