10 January 2014

Regular Expressions Cookbook: Errata

Nuevo errata encontrado, ahora es uno matemático de una fórmula mal escrita... me imagino que el autor sabia que poner, pero se tuvo que traspapelar la fórmula.

http://www.oreilly.com/catalog/errataunconfirmed.csp?isbn=0636920023630

Footnote 2:

If there are n characters between the double quote and the end of the string, the regex engine will try 2 1/n permutations of ‹ (?:[^"\r\n]+|"")* ›

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it appears: 2^(1/n)
(this trends to 1, when n grows)

however, it must say 2^(n-1)
when n=4 the number of permutations is 8.
(thus, it has an exponential behaviour).

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