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- Subject: Re: PIL 3rd electronic version
- From: Finn Wilcox <finnw@...>
- Date: Wed, 15 May 2013 13:01:12 +0100
On 15/05/2013 10:28, steve donovan wrote:
> On Wed, May 15, 2013 at 11:07 AM, Finn Wilcox <email@example.com
> <mailto:firstname.lastname@example.org>> wrote:
> -- defines a factorial function
> function fact (n)
> Excellent command of written Martian displayed here, but what's the trick?
It's just a substitution cipher, i.e. each character is globally
replaced by another. I don't have the .pdf, but I am guessing they
generate a random permutation of the codepoints used in the document and
embed a font whose glyphs have the same permutation applied.
And it is easy to guess which is which if you are familiar with the
language. In this case I started with ❡♥❞, which I guessed meant "end"
as it appears twice on a line by itself. That was enough to recognize
the remaining Lua keywords, followed by the words in the comment and
finally the punctuation.
But the point I was trying to make was that it is pretty much useless,
other than causing inconvenience (and for the target audience of a
programming book, that inconvenience is quite small.)