Can I generate code from string with macros?

[Joaquin Bello]

Hi, I'm tired of writing dumb fill code, so I'm trying to create something that generates code like this

createNode(aEntity:Entity):Node

{

var node:MotionNode=new MotionNode();

node.position=cast(aEntitiy.get(Position.ID)); //assigns a property 

node.motion=cast(aEntity.get(Motion.ID));

return node;

}

I don't want to create a generic function using RTTI for speed reasons.

I want to create a macro with a firm like this

 

autoNodeCreation(aEntity:Entity, node:String or class)

The first trouble I have is that Position.ID is a static Int generated  with a @:autoBuild , I can't find a way to reference the class inside the macro without an error.

 Inside the macro I manage to find the fields(name and type) of the Node.

 So I was wondering if there's a way to use macros to just insert code(string) so at runtime I know Position.ID is generated.

Hope it's not too confusing what I want to do.

Thanks and any help would be great!

[Joaquin Bello]

So I made a working demo, apparently the code is working and the js result code looks right.  

Here my ugly copy paste from many examples from the web, I post it for future references.

macro public static function generateExtraMethods(nodeType:String):Array<Field> {

 

 var code:String;

 var exp:Array<Expr> = new Array();

  switch (haxe.macro.Context.getType(nodeType))

{

 case TInst(cl, _)://couldn't find another way to RTTI the class without an instance

 code = "var _node:" + nodeType+" = new " + nodeType+"()"; //example: var node:MotionNode=new MotionNode();

exp.push(Context.parseInlineString(code, Context.currentPos()));

var array = cl.get().fields.get();

for (i in array) 

{

code = "_node." + i.name+" = cast(aEntity.get(" + i.type.getParameters()[0].toString() + ".ID)) ";   //example: node.position=cast(aEntitiy.get(Position.ID));

exp.push(Context.parseInlineString(code, Context.currentPos()));

}

 code = "return _node";    //return node

 exp.push(Context.parseInlineString(code, Context.currentPos()));

 

 case _: 

 trace("Macro error wrong type, look at : " + Context.currentPos);

}

var c = macro : {

public function createNode(aEntity:Entity):PropertyNode{  //need to import Entity and PropertyNode in the class that use @build

$b { exp } //this turns the array into a single expr

}

}

switch (c) {

case TAnonymous(fields):

return Context.getBuildFields().concat(fields);

default:

throw 'unreachable';