### Abstract

In a recent paper (M. Barash, A. Okhotin, "Defining contexts in context-free grammars", LATA 2012), the authors introduced an extension of the context-free grammars equipped with an operator for referring to the left context of the substring being defined. This paper proposes a more general model, in which context specifications may be two-sided, that is, both the left and the right contexts can be specified by the corresponding operators. The paper gives the definitions and establishes the basic theory of such grammars, leading to a normal form and a parsing algorithm working in time O{script}(n^{4}), where n is the length of the input string.

Original language | English |
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Pages (from-to) | 94-108 |

Number of pages | 15 |

Journal | Electronic Proceedings in Theoretical Computer Science, EPTCS |

Volume | 151 |

DOIs | |

Publication status | Published - 21 May 2014 |

Event | 14th International Conference on Automata and Formal Languages, AFL 2014 - Szeged Duration: 27 May 2014 → 29 May 2014 |

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### Scopus subject areas

- Software

### Cite this

*Electronic Proceedings in Theoretical Computer Science, EPTCS*,

*151*, 94-108. https://doi.org/10.4204/EPTCS.151.6

}

*Electronic Proceedings in Theoretical Computer Science, EPTCS*, vol. 151, pp. 94-108. https://doi.org/10.4204/EPTCS.151.6

**Grammars with two-sided contexts.** / Barash, Mikhail; Okhotin, Alexander.

Research output

TY - JOUR

T1 - Grammars with two-sided contexts

AU - Barash, Mikhail

AU - Okhotin, Alexander

PY - 2014/5/21

Y1 - 2014/5/21

N2 - In a recent paper (M. Barash, A. Okhotin, "Defining contexts in context-free grammars", LATA 2012), the authors introduced an extension of the context-free grammars equipped with an operator for referring to the left context of the substring being defined. This paper proposes a more general model, in which context specifications may be two-sided, that is, both the left and the right contexts can be specified by the corresponding operators. The paper gives the definitions and establishes the basic theory of such grammars, leading to a normal form and a parsing algorithm working in time O{script}(n4), where n is the length of the input string.

AB - In a recent paper (M. Barash, A. Okhotin, "Defining contexts in context-free grammars", LATA 2012), the authors introduced an extension of the context-free grammars equipped with an operator for referring to the left context of the substring being defined. This paper proposes a more general model, in which context specifications may be two-sided, that is, both the left and the right contexts can be specified by the corresponding operators. The paper gives the definitions and establishes the basic theory of such grammars, leading to a normal form and a parsing algorithm working in time O{script}(n4), where n is the length of the input string.

UR - http://www.scopus.com/inward/record.url?scp=84938927607&partnerID=8YFLogxK

U2 - 10.4204/EPTCS.151.6

DO - 10.4204/EPTCS.151.6

M3 - Conference article

AN - SCOPUS:84938927607

VL - 151

SP - 94

EP - 108

JO - Electronic proceedings in theoretical computer science

JF - Electronic proceedings in theoretical computer science

SN - 2075-2180

ER -