Sierpinski triangle: 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`.

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

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

depending on the command-line options used

and the location of the included file.

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

# Compute the curve using a Lindenmayer system of rules

def rules:

# "H" signfies Horizontal motion

{X: "XX",

H: "H--X++H++X--H",

"": "H--X--X"};

def sierpinski($count):

rules as $rules

| def repeat($count):

if $count == 0 then .

else gsub("X"; $rules["X"]) | gsub("H"; $rules["H"])

| repeat($count-1)

end;

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

def interpret($x):

if $x == "+" then turtleRotate(-60)

elif $x == "-" then turtleRotate(60)

else turtleForward(20)

end;

def sierpinski_curve($n):

sierpinski($n)

| split("")

| reduce .[] as $action (

turtle([200,-200]) | turtleDown;

interpret($action) ) ;

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

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

def svg:

"<svg viewBox='\(.minx|floor) \(.miny - 4 |floor) \(.maxx - .minx|ceil) \(6 + .maxy - .miny|ceil)'",

" preserveAspectRatio='xMinYmin meet'",

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

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

"</svg>";

sierpinski_curve(5)

| svg</lang>