JSON-schema type builder prototype.

mytype.json

{
    "type": "object",
    "required": ["intProp", "boolProp"],
    "properties": {
        "intProp": {"type": "integer"},
        "numProp": {"type": "number"},
        "strProp": {"type": "string"},
        "boolProp": {"type": "boolean"},
        "arrayProp": {
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "dynObj": {"type": "object"},
                    "dynArr": {"type": "array"}
                }
            }
        }
    }
}

SchemaTypeBuilder.hx

#if macro
import haxe.macro.Context;
import haxe.macro.Expr;

class SchemaTypeBuilder
{
    public static function build(ref:String):haxe.macro.Type
    {
        var schema = haxe.Json.parse(sys.io.File.getContent(ref));
        var type:ComplexType = parseType(schema);
        return haxe.macro.ComplexTypeTools.toType(type);
    }

    static function parseType(schema:Dynamic):ComplexType
    {
        return switch (schema.type)
        {
            case "integer":
                return macro : Int;
            case "number":
                return macro : Float;
            case "string":
                return macro : String;
            case "boolean":
                return macro : Bool;
            case "array":
                parseArrayType(schema);
            case "object":
                parseObjectType(schema);
            case unknown:
                throw "Unsupported JSON-schema type: " + unknown;
        };
    }

    static function parseArrayType(schema:Dynamic):ComplexType
    {
        var type = if (Reflect.hasField(schema, "items"))
            parseType(schema.items);
        else
            macro : Dynamic;

        return macro : Array<$type>;
    }

    static function parseObjectType(schema:Dynamic):ComplexType
    {
        if (Reflect.hasField(schema, "properties"))
        {
            var required:Array<String> = Reflect.hasField(schema, "required") ? schema.required : [];
            var fields:Array<Field> = [];
            var props = schema.properties;
            for (field in Reflect.fields(props))
            {
                var meta = [];
                if (!Lambda.has(required, field))
                    meta.push({name: ":optional", params: [], pos: Context.currentPos()});
                var subschema = Reflect.field(props, field);
                fields.push({
                    name: field,
                    pos: Context.currentPos(),
                    kind: FVar(parseType(subschema)),
                    meta: meta
                });
            }
            return TAnonymous(fields);
        }

        return macro : Dynamic<Dynamic>;
    }
}
#end

Usage.hx

class Sample
{
    static function main()
    {
        var a:MyType = {
            intProp: 10,
            boolProp: true
        };
    }
}

typedef MyType = haxe.macro.MacroType<[SchemaTypeBuilder.build("mytype.json")]>;