Creating a function in a macro

Question

I am trying to add a static variable and a static function to all instances of a class and its child classes using @:buildand macros @:autoBuild.

I managed to get a static variable to work, but I have no idea how to "build" a function from various EFunction, EForetc.

Here is the code I have:

macro static public function addGetId() :Array<Field>
{
    var fields : Array<Field> = Context.getBuildFields();

    // The static _id field
    var idField = {
        name : "_id",
        doc : null,
        meta : [],
        access : [AStatic, APrivate],
        kind : FVar(macro : Int, macro -1),
        pos : Context.currentPos()
    };

    // The getId function field
    var getIdField = {
        name : "getId",
        doc : "Returns the ID of this command type.",
        meta : [],
        access : [AStatic, APublic],
        kind : FFun({
            params : [],
            args : [],
            expr: // What do I have to write here???
            ret : macro : Int
        }),
        pos : Context.currentPos()
    };

    fields.push(idField);
    fields.push(getIdField);
    return fields;
}

Here's what the function that I want to add in regular code would look like if it were actually in the .hx file:

public static function getId() : Int
{
    if (_id == -1)
    {
        _id = MySingleton.getInst().myGreatFunction()
    }
    return _id;
};

Thus, it refers to a newly added variable _idas well as to some function of the singleton class.
So: How would getIdField()complete getIdField()?

:
- , - . , ?

:
params args FFun?

Answer 1

reification, , Haxe:

expr: macro {
    if (_id == -1) {
        _id = 0;
    }
    return _id;
},

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params - , args - , . Haxe , :

:

. Haxe , .