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Re: Sunflower Spiral . . . Re: L-systems in PS

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On Saturday, July 28, 2012 8:59:54 PM UTC-5, tlvp wrote:
> On Sat, 28 Jul 2012 14:13:16 -0700 (PDT), luser- -droog wrote:
> 
> 
> 
> > ... So parameters evaluate to numbers and then
> 
> > just occur in the arrays and get used
> 
> > where needed. ...
> 
> 
> 
> In my book, the terms parameter, index, and (numerical) variable have
> 
> always been pretty much interchangeable :-) . HTH. Cheers, -- tlvp
> 

Well, yeah. It isn't radically different in that respect.
But it does mean that the productions need to be partially
evaluated at each step. In other cases, the parameter may
select among several productions, as well as evaluate in 
the selected procedure.

It turns out I didn't implement the brackets correctly
in that last one, so here's the fixup.

563(1)10:39 PM:lsys 0> cat sunf.ps
%!
%Sunflower Spiral
%From ABOP Section 4.1

<<
    /a 137.5
    /A {
        /n exch def
        [ a /+ cvx /[ cvx n .5 exp /f cvx /D cvx /] cvx n 1 add /A cvx ] cvx
    }
    /DOL {
        {
            [ exch {
                currentdict exch 2 copy known {
                    get exec aload pop
                }{
                    exch pop
                } ifelse
            } forall ]
        } repeat cvx
    }
    /Dexec {
        {
            dup type /arraytype eq {
                Dexec
            }{
                exec
            } ifelse
        } forall
    }
>>begin

/graphics <<
    ([) { gsave }
    (]) { grestore }
    /F { 0 rlineto }
    /f { 0 rmoveto }
    /+ { rotate }
    /- { neg rotate }
    /r .5
    /innercolor { .5 setgray }
    /D { gsave
            currentpoint r 0 rmoveto
            r 0 360 arc
            gsave innercolor fill grestore
            stroke
         grestore }
>> def

{ 0 A } 1000 DOL

300 400 translate
0 0 moveto
1 10   dup dup scale
div setlinewidth
graphics begin
    Dexec clear
end

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L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-25 23:34 -0700
  Pastel Forests . . . Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-27 10:05 -0700
    Stochastic Weeds . . . Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-28 01:21 -0700
      Sunflower Spiral . . . Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-28 14:13 -0700
        Re: Sunflower Spiral . . . Re: L-systems in PS tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2012-07-28 21:59 -0400
          Re: Sunflower Spiral . . . Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-28 20:41 -0700
            Fancy Dingbats. . . Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-07-29 22:54 -0700
  Hilbert Space-Curve, Re: L-systems in PS luser- -droog <mijoryx@yahoo.com> - 2012-09-20 23:35 -0700

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