Functions in an array?

MalaLal

Hi, I was wondering if it was possible to pass functions in an array.

I have seven functions that produce patterns, I wanted to know if I could put them in an array which I can then use in a 'for i' statement and rotate each odd number in the array anti-clockwise and each even number clockwise.

PhiLho

You have to wrap each function in a class.

PhiLho

Example, using anonymous classes made after an interface:

interface F
{
  float f(float v);
}

F[] functions =
{
  new F() { float f(float v) { return v * 2; } },
  new F() { float f(float v) { return v + 20; } },
  new F() { float f(float v) { return v * v; } },
};

void setup()
{
  float val = 3.14;
  for (int i = 0; i < functions.length; i++)
  {
    println(functions[i].f(val));
  }
}

GoToLoop

Java doesn't have the function type! Hence it can't store such references in variables! 8-X
However, we can use methods from interfaces & classes as sorta replacement as @PhiLho has shown above.
Some other languages can though. Like JavaScript, Lua, C, etc.! :ar!
Java 8's gonna get something similar soon! <:-P

mcspud

Wow, cool (Java 8)

Yea, just use a class.

GoToLoop

I wouldn't have my hopes too high too soon in regards to Processing + Java 8.
Shamefully, Processing's pre-processor got problems even w/ something as basic as enum.
Imagine when dealing w/ lambda expressions or method references!

Chrisir

I usually just store a commandID and name the different commands (which are just int)

and then I have a function somewhere

void excuteCommandID (commandID)
switch (commandID) { 
case cmdGoLeft:
 // call a function
break;

GoToLoop

(which are just int)

Java 7 accepts String for switch ()! :-c

PhiLho

To be pedantic, encapsulating a single function inside a general class is called the Command pattern. It is a very useful design pattern to know. :-)