15 Oct 2005 12:59:55 -0400

Related articles |
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terminological problem Meyer-Eltz@t-online.de (Detlef Meyer-Eltz) (2005-10-13) |

Re: terminological problem (EBNF & regular expressions) paul@parsetec.com (Paul Mann) (2005-10-14) |

Re: terminological problem (EBNF & regular expressions) Meyer-Eltz@t-online.de (Detlef Meyer-Eltz) (2005-10-15) |

Re: terminological problem (EBNF & regular expressions) paul@parsetec.com (Paul Mann) (2005-10-17) |

Re: terminological problem (EBNF & regular expressions) paul@parsetec.com (Paul Mann) (2005-10-19) |

Re: terminological problem (EBNF & regular expressions) Meyer-Eltz@t-online.de (Detlef Meyer-Eltz) (2005-10-19) |

Re: terminological problem (EBNF & regular expressions) paul@parsetec.com (Paul Mann) (2005-10-20) |

Re: terminological problem (EBNF & regular expressions) Meyer-Eltz@t-online.de (Detlef Meyer-Eltz) (2005-10-23) |

Re: terminological problem (EBNF & regular expressions) paul@parsetec.com (Paul Mann) (2005-10-26) |

[1 later articles] |

From: | Detlef Meyer-Eltz <Meyer-Eltz@t-online.de> |

Newsgroups: | comp.compilers |

Date: | 15 Oct 2005 12:59:55 -0400 |

Organization: | Compilers Central |

References: | 05-10-082 05-10-093 |

Keywords: | parse |

Because of my terminologic problem I could not explain my terminologic

problem. Nevertheless your answer is interesting for me.

First I try to explain my problem again: I think it is a widespread

opinion, that regular expressions are written with a notation using

'?', '*' and '+', as this notation is used in many text processing

software. I am looking for a word for this kind of regular

expressions. I want to contrast them against regular expressions with

a notation with [...], {...} and from expressions using recusiv rules.

I want to emphasize, that

one has not to learn a new grammar, to use the TextTransformer

--------------------------------------------------------------

It is a strong feature of your lexer grammar, that it can handle

nested comments. By regular expressions this is not possible. Non

nesting block comments can be defined with the TextTransformer as:

<comment1b> -> /\*[^*]*\*+([^/*][^*]*\*+)*/

But in other respects regular expressions are more concise than a

lexer grammar. Often, predefined character classes or their negations

are sufficient for the definition of tokens.

The translation of your examples is:

<identifier> -> [A-Za-z_]\w*

<integer> -> \d+

<spaces> -> \s+ // to translate your example exactly: [\t\n ]+

<comment2> -> //[^\n]*

Regards

Detlef Meyer-Eltz

--

mailto:Meyer-Eltz@t-online.de

http://www.texttransformer.de

http://www.texttransformer.com

http://www.texttransformer.org

http://www.text-konverter.homepage.t-online.de

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