How to use an array as arguments in a function?

Question

Hello! 
 
 I'm working in a analog watch face, in which there is a filled circle at the end of the hour, minute and second hands. The code was working well, until I tried to condense it and write a function to set the hand coordinates (like the analog example, provided in the SDK). Then I will only get a "Error: Not Enough Arguments Error" console response. 
 This is the code, working as it should: 
 targetDc.fillCircle(
 center[0] + (center[0] - 50) * Math.cos(hourHandAngle),
 center[1] + (center[1] - 50) * Math.sin(hourHandAngle), 
 7
 ); 
 And there goes the function, arguments returned of it, and the console error log: 
 function handAttributes(center, distance, angle, radius) {
 var attrib = new [3];
 attrib = [
 center[0] + (center[0] - distance) * Math.cos(angle),
 center[1] + (center[1] - distance) * Math.sin(angle),
 radius];
 return attrib;
	}
	
 function onUpdate(dc) {
 var width = targetDc.getWidth();
 var height = targetDc.getHeight();
 var clockTime = System.getClockTime();
 var center = [width/2, height/2];

 System.println(handAttributes(center, 50, hourHandAngle, 7));
 
 targetDc.fillCircle(handAttributes(center, 50, hourHandAngle, 7)
 );
 } 
 [130.000000, 50.000000, 7] <--- It seems the function is working fine, returning an array with 3 values in it. 
 Error: Not Enough Arguments Error 
 Details: Failed invoking <symbol> 
 
 I am an absolute newbie in coding in general, and I'm probably missing something silly here, but can't figure it out! I'm using the latest SDK, and using mostly the Vivoactive 3 music as a simulator. Any suggestions?

Travis.ConnectIQ · Accepted Answer

As jim_m_58 pointed out, you have to unpack the array returned from your handAttributes function. Some languages support unpacking sequences into parameter lists: >>> def f(a, b, c):
... print('a={} b={} c={}'.format(a, b, c))
... 
>>> array = [ 1, 2, 3 ]
>>> f(*array)
a=1 b=2 c=3
>>> tuple = ( 4, 5, 6 )
>>> f(*tuple)
a=4 b=5 c=6 
 Unfortunately, MonkeyC doesn't support this feature. You have to do it yourself. 
 One other note. Your code handAttributes is allocating an array for attrib twice. You can save yourself one allocation by making one of these small tweaks: 
 function handAttributes(center, distance, angle, radius) {
	return [
 center[0] + (center[0] - distance) * Math.cos(angle),
 center[1] + (center[1] - distance) * Math.sin(angle),
 radius
 ];
}

// or

function handAttributes(center, distance, angle, radius) {
	var attrib = new [3];
	attrib[0] = center[0] + (center[0] - distance) * Math.cos(angle);
	attrib[1] = center[1] + (center[1] - distance) * Math.sin(angle);
 attrib[2] = radius;
	return attrib;
}

How to use an array as arguments in a function?

Top Replies

All Replies