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    amanda.hinchman-dominguez

    10/31/2018, 11:54 PM
    Revisiting filter functions tonight for Kotlin Thursdays, but I decided to try my hand at improving code I wrote up a while ago. I know I'm close, but what's off is that I need a way to say that I don't know what the parameters for a function I want to pass in might be. Thoughts?
  • a

    amanda.hinchman-dominguez

    10/31/2018, 11:55 PM
    Not_sure_how_to_pass_a_filter_function_in_if_I_don_t_care_about_the_parameters_until_the_function_is_executed.kt
    Not_sure_how_to_pass_a_filter_function_in_if_I_don_t_care_about_the_parameters_until_the_function_is_executed.kt
  • a

    amanda.hinchman-dominguez

    11/01/2018, 12:07 AM
    This is not what I was supposed focusing on tonight but I got really interested because I was looking at at the way Controls implement some of these events haha
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    amanda.hinchman-dominguez

    11/01/2018, 12:07 AM
    otherwise, it'd be 
    or(a.getColor(x,y), b.getColor(x,y))
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    iari

    11/01/2018, 12:49 AM
    @amanda.hinchman-dominguez try ::or
    😮 1
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    iari

    11/01/2018, 12:55 AM
    what you described is by the referred to as point-free style (particularly in the Haskell community) (apparently also "tacit programming, but I hadent heard that so far - see https://en.wikipedia.org/wiki/Tacit_programming) Pointfree style in Java and Kotlin is done with the double-colon operator
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    amanda.hinchman-dominguez

    11/01/2018, 1:58 AM
    oh! That's the self-reflective thing that Kotlin allows. I had no idea it had a name 😆
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    amanda.hinchman-dominguez

    11/01/2018, 2:00 AM
    I COMPLETELY forgot about this option. to be honest, I don't really know how it works. I'll be sure to look into it.
  • i

    iari

    11/01/2018, 2:12 AM
    Its a way to obtain a Pointer to the Function. you could also write: myfun = { i1: Image, i2: Image -> ...stuff... } and the pass myfun.
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    amanda.hinchman-dominguez

    11/01/2018, 2:14 AM
    okay, now I REALLY have to look into this.
  • i

    iari

    11/01/2018, 2:15 AM
    (I might have messed up the kotlin syntax there a bit)
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    amanda.hinchman-dominguez

    11/01/2018, 2:15 AM
    I feel like the documentation in Kotlin doesn't explain it really well tbh
  • i

    iari

    11/01/2018, 2:16 AM
    that may be - i havent looked at it so much, as it is pretty much the same as in plain java >=8
  • i

    iari

    11/01/2018, 2:16 AM
    from what I can tell
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    amanda.hinchman-dominguez

    11/01/2018, 2:18 AM
    oh, that's really helpful. I guess I wasn't sure if it was a Kotlin specific reflective feature or not
  • i

    iari

    11/01/2018, 2:21 AM
    https://kotlinlang.org/docs/reference/reflection.html Is that what you meant by the kotlin doc, which isn't explaining it so well?
  • a

    amanda.hinchman-dominguez

    11/01/2018, 2:21 AM
    yep, that's the one!
  • i

    iari

    11/01/2018, 2:23 AM
    I don't know if that is helpful to you, but I like to not think about this thing not so much as in the java/reflection terms, but more in functional terms
  • i

    iari

    11/01/2018, 2:24 AM
    Someone smarter than me might is welcome to correct me - but from how I understand it, it goes like this:
  • i

    iari

    11/01/2018, 2:25 AM
    usually in a real functional language there is no distinction between some regular data instance and a function - they are all "first class" thingies
  • i

    iari

    11/01/2018, 2:26 AM
    in Java (and kotlin for that matter) however, theres functions/methods, which are something different
  • i

    iari

    11/01/2018, 2:26 AM
    so the :: is needed to turn it into an actual function object
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    iari

    11/01/2018, 2:29 AM
    if you do find out more, or stumble upon a good article, let me know
  • i

    iari

    11/01/2018, 2:42 AM
    but the :: actually does something to the function: it binds the context of the referenced function to the function
  • a

    amanda.hinchman-dominguez

    11/01/2018, 2:43 AM
    I guess what I'm wondering is how parameters come in play with ::
  • i

    iari

    11/01/2018, 2:44 AM
    If youve done webdev/javascript, you might have come across usages of Function.prototype.bind() ?
  • i

    iari

    11/01/2018, 2:59 AM
    Heres some code to illustrate - I do not really understand myself, why this distinction is needed ...
    Untitled.java
  • i

    iari

    11/01/2018, 3:03 AM
    maybe its just necessary for Java interop ...
  • a

    amanda.hinchman-dominguez

    11/01/2018, 3:08 AM
    my guess is that maybe with the 
    ::
    it treats variable inputs like splat? I could be wildly wrong
  • a

    amanda.hinchman-dominguez

    11/01/2018, 3:08 AM
    As for Function.prototype.bind(), it's been a while since I have done frontend dev, but sure 😄
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