Tue, 25 May 1993 14:16:57 GMT

Related articles |
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Regular LALR grammars simonh@swidev.demon.co.uk (1993-05-25) |

Re: Regular LALR grammars markh@csd4.csd.uwm.edu (1993-05-26) |

Newsgroups: | comp.compilers |

From: | simonh@swidev.demon.co.uk (Simon Huntington) |

Keywords: | LALR, parse, question |

Organization: | SoftWare Interrupt Developments |

Date: | Tue, 25 May 1993 14:16:57 GMT |

How are regular parser grammars handled by the parser generator? I know

how a grammar using regular expressions (ie. EBNF) can be converted to

BNF, but does a regular-grammar parser use the regular expressions during

closure? ie.

x -> a*

what would the Closure of: x -> . a*

be:

x -> . a

-> a . ?

If this is correct, I assume + and optional [] are handled similarly:

for x -> .a+

closure of: x -> .a+

is: x -> .a

closure of: x -> a+.

is: x -> a.

-> .a

for x -> [a]

closure of: x -> .[a]

is: x -> .a

-> a.

Is this correct or will it have the same effect as transforming the grammar

to BNF-form only?

--

Simon Huntington

Software Interrupt Developments. Leeds, UK.

--

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