Sierpinski curve: Difference between revisions

=={{header|jq}}==

{{works with|jq}}

'''Works with gojq, the Go implementation of jq'''

This entry uses an L-system and turtle graphics to generate an SVG

file which can be viewed using a web browser, at least if the file type is `.svg`. The SVG viewBox is dynamically sized.

See [[Category_talk:Jq-turtle]] for the turtle.jq module used here.

Please note that the `include` directive may need to be modified

depending on the location of the included file, and the command-line

options used.

<lang jq>include "turtle" {search: "."};

# Compute the curve using a Lindemayer system of rules

def rules:

{ X: "XF+G+XF--F--XF+G+X",

"": "F--XF--F--XF" };

def sierpinski($count):

rules as $rules

| def p($count):

if $count == 0 then .

else gsub("X"; $rules["X"]) | p($count-1)

end;

$rules[""] | p($count) ;

def interpret($x):

if $x == "+" then turtleRotate(45)

elif $x == "-" then turtleRotate(-45)

elif $x == "F" or $x == "G" then turtleForward(5)

else .

end;

def sierpinski_curve($n):

sierpinski($n)

| split("")

| reduce .[] as $action (

turtle([100,100]) | turtleDown;

interpret($action) ) ;

# viewBox = <min-x> <min-y> <width> <height>

# Input: {svg, minx, miny, maxx, maxy}

def svg:

"<svg viewBox='\(.minx|floor) \(.miny - 2 |floor) \(.maxx - .minx|ceil) \(2 + .maxy - .miny|ceil)'",

" preserveAspectRatio='xMinYmin meet'",

" xmlns='http://www.w3.org/2000/svg' >",

path("none"; "red"; 1),

"</svg>";

sierpinski_curve(5)

| svg

</lang>