Abstract enum -> macro build static func

[Théo Sabattié]

Hi,

I would like know if a string can be an @:enum abstract

I didn't find specific method for that, so I decided to use an iteration on enum abstract to know if value exist or not.

Task is needed in a lot of @:enum abstract so I wanted use macro, but I have some difficulty...

From:

@:enum abstract Primary(String) to String 

{

    var FLOAT  = "Float";

    var INT    = "Int";

    var STRING = "String";

    var BOOL   = "Bool";
}

I would like obtain:

@:enum abstract Primary(String) to String 

{

    var FLOAT  = "Float";

    var INT    = "Int";

    var STRING = "String";

    var BOOL   = "Bool";

    private static var values:Array<String> = ["Float", "Int", "String", "Bool"];

    public static function getAllValues():Array<String> {
        return values.slice(0);
    }

    public static function hasValue(value:String){
        return values.indexOf(value) != -1;
    }
}

in an additive way, an other macro to add:

@:enum abstract Primary(String) to String 

{

    var FLOAT  = "Float";

    var INT    = "Int";

    var STRING = "String";

    var BOOL   = "Bool";

    private static var values:Array<String> = ["Float", "Int", "String", "Bool"];

    public static function getAllValues():Array<String> {
        return values.slice(0);
    }

    public static function hasValue(value:String){
        return values.indexOf(value) != -1;
    }

    private inline function new(s:String) {

        this = s;

    }

    @:from

    static public function fromString(s:String) {

        if (!Primary.hasValue(s)) {

            throw s + " does not exist on Primary";

        }

        return new Primary(s);

    }

}

Below, my current code:

#if macro

import haxe.macro.Context;

import haxe.macro.Type;

import haxe.macro.Expr;

using haxe.macro.Tools;

#end

class AbstractEnumBuildingMacro

{

    public static macro function build(typePath:Expr):Array<Field> {

        var type:Type           = Context.getType(typePath.toString());

        var fields:Array<Field> = Context.getBuildFields();

        var pos:Position        = Context.currentPos();

        var valueExprs          = [];

        

        switch (type.follow()) {

            case TAbstract(_.get() => ab, _) if (ab.meta.has(":enum")):

                valueExprs.push(macro "start");

                

                for (field in ab.impl.get().statics.get()) {

                    if (field.meta.has(":enum") && field.meta.has(":impl")) {

                        var fieldName = field.name;

                        valueExprs.push(macro $typePath.$fieldName);

                    } else {

                        valueExprs.push(macro false);

                    }

                }

                

                valueExprs.push(macro "end");

                

            default:

                throw new Error(type.toString() + " should be @:enum abstract", typePath.pos);

        }

        

        var getAllValuesFunc:Function = { 

            expr: macro {

                return values.slice(0);

            },

            ret: (macro:Array<Dynamic>),

            args:[]

        }

        

        var hasValueFunc:Function = { 

            expr: macro {

                return values.indexOf(value) != -1;

            },

            ret: (macro:Bool),

            args:[ {

               name:"value", 

               type: (macro:Dynamic)

            }]

        }

        

        fields.push({

            name:  "values",

            access:  [Access.APrivate, Access.AStatic],

            kind: FieldType.FVar(macro:Array<String>, macro $a{valueExprs}), 

            pos: pos,

        });

        

        fields.push({

            name:  "getAllValues",

            access:  [Access.APublic, Access.AStatic],

            kind: FieldType.FFun(getAllValuesFunc), 

            pos: pos,

        });

        

        fields.push({

            name:  "hasValue",

            access:  [Access.APublic, Access.AStatic],

            kind: FieldType.FFun(hasValueFunc), 

            pos: pos,

        });

        

        return fields;

    }

}

1/ Functions seem valid but "values" is an empty array.

I take a part of the code from cookbook : http://code.haxe.org/category/macros/enum-abstract-values.html

Have you an idea to fix that?

2/ How can I get type of abstract and use it for function?

Thanks,

Théo Sabattié

[Théo Sabattié]

valueExprs.push(macro "start");
// ...
valueExprs.push(macro "end");

(It's just for test; there is not other expected values in array)

[Skial Bainn]

I'm not entirely familiar with build macros working on abstracts, but I've compiled your code and done some testing using Haxe 3.3.0+ and it looks like the implementation class has not been fully typed when your build macro has been called.

Loading the abstract type through a static macro call with `Context.getType` and then accessing the implementation class seems to return the built, see the small gist for an example.

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[Cambiata]

Just for the record, there's this article on the Haxe Code Cookbook:
http://code.haxe.org/category/macros/enum-abstract-values.html

Jonas

[Skial Bainn]

Good point, I missed that in the original message :)

--

[Théo Sabattié]

Just for the record, there's this article on the Haxe Code Cookbook: 

Thanks @Cambiatia, but I talk about that in my first message...

I wanted get that on a build macro and stock it in static var.

1/ Functions seem valid but "values" is an empty array.

I take a part of the code from cookbook : http://code.haxe.org/category/macros/enum-abstract-values.html

Have you an idea to fix that?

Ok' @skial, thanks for analysis and testing.

Temporary I did that:

@:enum abstract EnumPrimary(String) to String 

{

    var FLOAT  = "Float";

    var INT    = "Int";

    var STRING = "String";

    var BOOL   = "Bool";

    private static var values:Array<String> = AbstractEnumTools.getValues(EnumPrimary);

    public static function getAllValues():Array<String> {

        return values.slice(0);

    }

    

    public static function hasValue(value:String){

        return values.indexOf(value) != -1;

    }

    private inline function new(s:String) {

        this = s;

    }

    @:from

    static public function fromString(s:String) {

        if (!hasValue(s)) {

            throw s + " does not exist on Primary";

        }

        return new EnumPrimary(s);

    }

}

So I have to repeat code on lot of my enum... 

It's pity for build macro.

Does someone know a better way to use build macro? :3

Le jeudi 18 août 2016 09:54:51 UTC+2, Théo Sabattié a écrit :