OpenEuphoria

2. Re: fake class in OE

• Posted by Icy_Viking Feb 22, 2021
• 1267 views

Success = setclass("cow1","color","brown") 

ListOfParameters = getclass("cow","walking") 

I like this idea. Perhaps once struct supported is added, this can be added next. Or a feature to be added in the future?

4. Class/Interface/Contract -- Re: fake class in OE

• Posted by mitgedanken Feb 23, 2021
• 1188 views

--[ <built-in> 
--[+ About An Interface 
---   
--+] 
interface Class 
  --[ About A Contract 
  -- a "contract name" is optional, 
  -- it is not to be the same name as the routine or variable. 
  -- could be used for error reporting. 
  -- If a contract is not satisfied an error will occur (aka ##error:crash()##) 
  -- example: (# is like : for namespace. I choose that to differ from namespaces -- i.e. instead of ::) 
  --   sequence message = {Class#contract[_NAME_], Class#contract[_REQUIREMENTS_]} 
  --   crash_message("Contract %s not satisfied!\nRequirements: %s", message) 
  --] 
   
  contract create 
    atom class_pointer: -1 <= return >= 0 
    export procedure create() return class_pointer 
    docline "-1 means error, >= 0 means 'This is my pointer and I love you so much!'" 
  end contract 
   
   
  --[ About @ 
  --- @ could be a routine name and will be (auto-) called if its Requirements are not satisfied 
  --- I think for ClassError it must be a procedure. 
  --- And the format (fmt) of ##error:crash_message(sequence fmt)## is optional to use 
  --- example: 
  ---   fmt could be by default: sprintf("%s is neither %d nor %d", {...}) 
  ---   fmt by user would be used like any ##sprintf##  i.e. @ClassError("...", {...}) 
  --- See: [["About A Contract"]] 
  --] 
 
  contract destroy 
    integer code return >= 1  @ClassError -- should it be @ClassError() ?? 
            or   return <= 0  @ClassError --- 
    export function destroy() return code 
    docline "<= 0 means no error and >= 1 means an error" 
  end contract 
   
  --- More (explicit) contracts if needed ... 
   
  --[ About 'magic routines' 
  --  It's magic if no function was defined 
  --  Like in other languages (Java, etc.) 
  --] 
   
  export function equal() return boolean 
  export function hash()  return sequence 
   
  export function serialize() return sequence 
  export procedure deserialize() 
  [...] 
end interface 
--] 
 
interface Animal: Class -- ": Class" is optional, any class/interface/contract/etc. will be inherited from Class 
  contract name 
    sequence name = "Animal" 
  end contract 
   
  -- Return name of Animal 
  contract 
    export function get_name(): string 
    return name: sequence 
  end contract 
   
  --- override in an interface is a 'silent' contract: this must be overridden! 
  override function equal() -- should a type-hint be required ?? 
  override function hash()  ---  
end interface 
 
class Cow: Animal 
  sequence name = "Cow" 
 
  export function get_name(): string 
    return name 
  end function 
 
  export function equal(@Class seq) 
     return equal(seq#name, name) 
  end function 
 
  export function hash() 
    return name 
  end function 
end class 
 
class Goat: Cow 
  override sequence name = "Goat" 
  [...] 
end class 

Goat#get_name() 

class_pointer goat_     = getclass("Goat") -- or get_class("Goat")  -- is case-insensitive 
method_return goat_name = getmethod(goat_, "get_name", {})          -- same here 

class_pointer goat_ = class:new("Goat") 
method_return goat_name = class:method(goat_, "get_name", {}) 
-- or class:call(...) 
-- or class:func(..) / class:proc(...) 

--[ About "doc...end doc" and "docline" 
--- I think it's good practice to say which comment is more than a hint for the code owner. 
--] 

Forked into: [OE] Suggestion for OpenEuphoria 'Next' | Class/Interface/Contract

6. Class/Interface/Contract -- Re: fake class in OE

• Posted by irv Feb 23, 2021
• 1179 views
• Last edited Feb 25, 2021

To expand on that (Pete will correct me if I'm wrong):

With Phix, a class can have public, or private, properties.

When you declare a property as public, it acts just like any other variable, except that it is "owned" by the class instance. Types work the same as they do elsewhere, but with an added feature (we get to that later).

class Cow 
  public integer horns; 
end class 
 
Cow bossie = new() ? bossie -- {"struct","Cow",4,1} instance 1 of class Cow 
Cow bessie = new() ? bessie -- {"struct","Cow",4,2} instance 2 of class Cow 
 
bessie.horns = 2 
bossie.horns = 0 
? bessie.horns -- prints 2 

If you declare a property as private, Phix looks for a routine of the same name, prepended by "set_" or "get_".

class Cow 
  private integer horns; 
   
  procedure set_horns(integer n)  
  -- we have a chance to do something in addition to just setting the number of horns 
  if n < 0 or n > 2 then ?"You're kidding, right?" -- made up example; 
  else this.horns = n end if 
  end procedure 
  
  function get_horns() 
   -- maybe do something here (beep once for each horn?) 
  return this.horns 
  end function 
 
end class 
 
? bossie.horns -- automatically calls function get_horns() for the bossie instance 
bessie.horns = 3 -- automatically calls procedure set_horns() for the bessie instance 

It will have, at the least, a label with some text, a button or two, and perhaps an Icon: So you will have written a Button class, an Image class, and a Label class. Then the Dialog might have either public or private properties of those types:

 
include Image.e -- exports declaration and code for class Image; 
 
class Dialog  
  private Image icon; 
 
  procedure set_icon(Image i)  -- will only accept an instance of Image class; 
    ? i -- {"struct","Image",6,1} <-- this is the instance passed to set_icon() 
    -- do something with that image (resize it, perhaps?) 
    this.icon = i 
    -- then update the dialog's icon, probably by calling a c_proc() In GTK, it would look something like: 
    c_proc(define_c_proc(GTK,"gtk_dialog_set_image",{C_POINTER,C_POINTER}),{this.handle,i.handle}) 
  end procedure 
 
end class 
 
Dialog d = new() 
Image x = new({"mongoose.jpg"}) 
d.icon = x -- calls the set_icon() function for class Dialog ,instance d, passing the Image structure; 

include Window.e -- exports declaration and code for class Window  
     -- the Window class declares a private sequence size; 
include Image.e  
 
class Dialog extends Window -- inherit properties and code from Window (can inherit from more than one class) 
  private Image icon; 
 
  procedure set_icon(Image i)  
    this.icon = i 
    -- update the dialog's icon 
  end procedure 
 
end class 
 
Dialog d = new() 
d.size = {300,400} -- calls the set_size() function in the Window class 
 
Image x = new({"mongoose.jpg"}) 
d.icon = x 

Now, anything that derives from a Window automatically has the ability to set or get its size.

8. Alternative: Module -- Re: fake class in OE

• Posted by katsmeow Feb 24, 2021
• 1050 views

Responding to mitgedanken ...

The problem with export function get_horns() is the same problem with most computer languages, and some people: it's fixed, the system is fixed, you cannot add a get_ anything else while the program is running, or any sort of parameter which you may discover next week. With this way of doing things, the programmer must know in advance all the possible things that could be setted or getted, and write code for it, which if you think about all the things in the world you know parameters about, is going to make for a terribly bloated application.

Responding to Icy_Viking ...

I hoped i was saying this could be written in OE and added soon as you are done, because i suggested it as an include file. There's no developers working on OE, there won't be any new releases (hasn't "release often" turned into 10 years now?). Phix seems to have a class that's as good as any language's. As i cannot write a real class for OE, i thought of a fake class. A beauty of it being OE source code is you can tweak it to suit your needs. For instance, use an external database for the parameters of each item and class, such as SQL?

Kat

10. Alternative: Module -- Re: fake class in OE

• Posted by Icy_Viking Feb 25, 2021
• 1038 views

Well yes a fake class is a good idea. True Phix does have a struct/class support. Also, yeah its been years since OE has had an official release.

12. Re: fake class in OE

• Posted by mitgedanken Feb 25, 2021
• 1018 views

Only a hint

14. Re: fake class in OE

• Posted by katsmeow Feb 25, 2021
• 999 views

Please, continue.

I hope i understand your meaning and i do not wander outside scope...

Ah, but there is if you use a preprocessor that re-writes the code. I made "varname" and varname access the same data for small amounts of shared_vars by simply using a case stack. And to know the name of the variable in OE's type system, you need only comment out the programmer's declaration, and insert your own unique type, which only that varname is type-checked with, ergo in that type-check code, it can be only one varname.

On startup, all the known data can be loaded as strings (vs enumerations in code?), and a case stack can equate "varname" and varname if necessary. Sure it can be done differently if OE/Phix had a variable_id().

Kat

16. Re: fake class in OE

• Posted by mitgedanken Feb 26, 2021
• 969 views

include std/map.e 
include std/socket.e as sock 
 
? routine_id( "map:new" ) -- default namespace 
? routine_id( "sock:create" ) -- custom namespace 

Yes, that's what I mean.
Then, you can use a constant to concat

constant ns = "sock:" 
sequence from_somewhere = "create" 
routine_id(ns & from_somewhere) -- equal to "sock:create" 

This is how I implement 'dynamic' plain OE modules.

18. Re: fake class in OE

• Posted by petelomax Feb 26, 2021
• 954 views

Only a hint, too

class Dude 
  public: 
    string fname, lname 
    atom age 
    procedure introduce() 
        printf(1,"Hi I'm %s %s and I use Phix!\n", {fname, lname})  
    end procedure 
end class 
      
Dude my_dude = new({"John", "Smith", 32})    
Dude cool_dude = new({"Ronald", "Weidner", 745}) 
      
my_dude.age = 22 
printf(1,"%s %s is %d\n",{my_dude.fname,my_dude.lname,my_dude.age}) 
cool_dude.introduce() 
      
{} = wait_key()