lambdaway :: fern

3 | list | login |load

| |

{svg {@ width="580" height="580" style="box-shadow:0 0 8px #000;"}
 {polyline  {@ points="{turtle 380 350 180 {T}}"
               stroke="#888" fill="transparent"}}
 {polyline  {@ points="{turtle 120 160 0 {F}}"
               stroke="#888" fill="transparent"}}
}

_h1 [[fractal_tree]] | fern | [[koch]] | [[stars]]

_h2 1) defining functions
{pre
'{def tree 
 {lambda {:s :n :a :b :c}
  {if {< :n 0}
   then 
   else M:s T:a 
          {tree {* :s :c} {- :n 1} :a :b :c}
        T-:a T-:b
          {tree {* :s :c} {- :n 1} :a :b :c} 
        T:b M-:s}}}
-> {def tree 
 {lambda {:s :n :a :b :c}
  {if {< :n 0}
   then 
   else M:s T:a 
          {tree {* :s :c} {- :n 1} :a :b :c}
        T-:a T-:b
          {tree {* :s :c} {- :n 1} :a :b :c} 
        T:b M-:s}}}

'{def fern 
 {lambda {:size :sign}
  {if {> :size 2}
   then M:size
        T{* 70 :sign}
          {fern {* :size 0.5} {- :sign}}
        T{* {- 70} :sign}
        M:size
        T{* {- 70} :sign}
          {fern {* :size 0.5} :sign}
        T{* 70 :sign}
        T{* 7 :sign}
          {fern {- :size 1} :sign}
        T{* {- 7} :sign}
        M{* -:size 2}
   else }}}
-> {def fern 
 {lambda {:size :sign}
  {if {> :size 2}
   then M:size
        T{* 70 :sign}
          {fern {* :size 0.5} {- :sign}}
        T{* {- 70} :sign}
        M:size
        T{* {- 70} :sign}
          {fern {* :size 0.5} :sign}
        T{* 70 :sign}
        T{* 7 :sign}
          {fern {- :size 1} :sign}
        T{* {- 7} :sign}
        M{* -:size 2}
   else }}}
}

_h2 2) building objects
{pre
'{def T {tree 100 10 30 45 0.7}}
-> {def T {tree 100 10 30 45 0.7}}
'{def F {fern 25 1}}
-> {def F {fern 25 1}}
}

_h2 3) drawing

{pre
'{svg {@ width="580" height="580" style="box-shadow:0 0 8px #000;"}
 {polyline  {@ points="{turtle 380 350 180 {T}}"
               stroke="#888" fill="transparent"}}
 {polyline  {@ points="{turtle 120 160 0 {F}}"
               stroke="#888" fill="transparent"}}
}
}

lambdaway v.20211111