From: Sandro Paganotti <sandro.paganotti@...>
Date: 2008-05-19T07:40:48+09:00
Subject: Re: [QUIZ] [SOLUTION] Obfuscated Email (#163)

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Really elegant !

On Sun, May 18, 2008 at 7:59 PM, Bill Kelly <billk@cts.com> wrote:

>
> From: "Matthew Moss" <matthew.moss@gmail.com>
>
>>
>> For your task this week, I ask that you make your own signature such that
>> displays your email address when run through the Ruby interpreter. The
>> signature must fit within four lines of no more than 80 characters per
>> line.
>> (If you still want to avoid outputting an email address, your script may
>> produce something else: a phone number, a funny quote, vCard, a poem to
>> your
>> love, whatever...)
>>
>
> Here's my solution... (longest line is 78 characters)
>
>
> ## Machines take me by surprise with great frequency. -- Alan Turing
> m=Hash[*"z_ymly_xolx_wclw_v.lv_uslu_ttlt_scls_r@lr_qklq_pllp_ollo_niln_mbl
> ".
> scan(/(..)(...)/).flatten];t=Hash.new("_");i,s=0,"z";loop{v=m[s+t[i]] or
> break
> s,t[i],d=v.split(//);i+=(d=="r")?1:-1};p t.keys.sort.map{|k|t[k]}.join
>
>
>
> As I missed last week's quiz, I decided to combine the two and implement a
> Turing Machine which would execute a program to
> write my email address to the tape, the print the tape contents.
>
> The Turing Machine program looks like this:
>
> # state, character_under_tape_head, new_state, char_to_write,
> move_left_right
> z_yml
> y_xol
> x_wcl
> w_v.l
> v_usl
> u_ttl
> t_scl
> s_r@l
> r_qkl
> q_pll
> p_oll
> o_nil
> n_mbl
>
>
> A slightly less obfuscated version of the solution follows.  (In the
> signature, I omitted using temporary variables when reading and writing
> the tape head t[i] .)
>
> ##--
>
> m=Hash[*"z_ymly_xolx_wclw_v.lv_uslu_ttlt_scls_r@lr_qklq_pllp_ollo_niln_mbl
> ".scan(/(..)(...)/).flatten]
>
> t=Hash.new("_")             # the tape
>
> i=0                         # tape index (negative index is OK)
>
> s="z"                       # current state register
>
> loop {
>  c = t[i]
>  v = m[s+c] or break
>  s,c,d = v.split(//)
>  t[i] = c
>  i += (d=="r")?1:-1
> }
>
> p t.keys.sort.map{|k|t[k]}.join
>
> ##--
>
>
> Regards,
>
> Bill
>
>
>
>


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