Sat, 26 Jul 2014 16:23:03 -0700

Related articles |
---|

LL vs LR parsing slkpg4@gmail.com (SLK Mail) (2014-07-26) |

From: | "SLK Mail" <slkpg4@gmail.com> |

Newsgroups: | comp.compilers |

Date: | Sat, 26 Jul 2014 16:23:03 -0700 |

Organization: | SLK Systems |

Keywords: | parse, tools |

Posted-Date: | 26 Jul 2014 17:12:13 EDT |

It does seem odd that all LR grammars can be made LR(1), but not the case

with LL. Intuitively, it may be that the constructive vs predictive nature

of the two is the cause. In LR, you only know what you have after you have

found it. In LL, you must predict what you think you have based on the

lookahead. So more lookahead equals more predictive power.

SLK now can generate LR(k) parsers in addition to LL(k). Parsing geeks may

be interested to know that the lookahead algorithm is the same for both.

This is because at any point in a parse, the lookahead is independent of

the direction of parse tree construction, i.e. up or down.

http://slkpg.1eko.com

Post a followup to this message

Return to the
comp.compilers page.

Search the
comp.compilers archives again.