Locating Free Positions in LR (k) Grammars

歐陽士庭(Shih-Ting Ouyang) ； 吳培基(Pei-Chi Wu) ； 王豐堅(Feng-Jian Wang)

《Journal of Information Science and Engineering》 18卷3期 (2002/05) Pp. 411-423

https://doi.org/10.6688/JISE.2002.18.3.3

並列摘要

LR (k) is the most general category of linear-time parsing. Before a symbol is recognized in LR parsing, it is difficult to invoke the semantic action associated with the symbol. Adding semantic actions to an LR (k) grammar may result in a non-LR (k) grammar. There are two straightforward approaches adopted by practitioners of parser generators. The first approach is to delay all semantic actions until the whole parse tree is constructed. The second is to add semantic actions to the grammar by chance. This paper presents an efficient algorithm for finding positions (called free positions) that can freely put semantic actions into an LR (k) grammar. The speedups of our method range from 2.23 to 15.50 times for the eight tested grammars.

並列關鍵字

parser generators ； LR k grammars ； semantic actions ； parse tree ； free positions