[macro] add SignletonMacro

src/main/haxework/macro/SingletonMacro.hx

@@ -0,0 +1,55 @@
+package haxework.macro;
+
+import haxe.macro.TypeTools;
+import haxe.macro.Context;
+import haxe.macro.ExprTools;
+import haxe.macro.Expr;
+import haxe.macro.Type;
+
+class SingletonMacro {
+
+    private static inline var metaName:String = ":singleton";
+
+    public static function has(classType:ClassType):Bool {
+        return classType.meta.has(metaName);
+    }
+
+    private var classType:ClassType;
+    private var fields:Array<Field>;
+
+    public function new(classType:ClassType, fields:Array<Field>) {
+        this.classType = classType;
+        this.fields = fields;
+    }
+
+
+    public function apply():Array<Field> {
+        var result:Array<Field> = fields.slice(0);
+        var classTypePath:TypePath = {
+            pack: classType.pack,
+            name: classType.name,
+        };
+        var type:ComplexType = TPath(classTypePath);
+        result.push({
+            name: 'instance',
+            access: [APublic, AStatic],
+            pos: Context.currentPos(),
+            kind: FProp('get', 'null', type),
+        });
+        var typeStr = classType.name;
+        result.push({
+            name: 'get_instance',
+            access: [APrivate, AStatic],
+            pos: Context.currentPos(),
+            kind: FFun({
+                args: [],
+                ret: type,
+                expr: macro $b{[
+                macro if (instance == null) instance = new $classTypePath(),
+                macro return instance
+                ]},
+            }),
+        });
+        return result;
+    }
+}

src/main/haxework/macro/Util.hx

@@ -1,7 +1,7 @@
 package haxework.macro;
 
-import haxe.macro.Type.ClassType;
 import haxe.macro.Expr;
+import haxe.macro.Type;
 
 class Util {
 

src/main/haxework/parser/Parser.hx

@@ -1,5 +1,6 @@
 package haxework.parser;
 
+import haxework.macro.SingletonMacro.SingletonMacro;
 import haxework.macro.StyleMacro;
 import haxe.macro.TypeTools;
 import haxe.macro.Context;
@@ -63,6 +64,11 @@ class Parser {
                     var style = new StyleMacro(ct, fields);
                     fields = style.apply();
                 }
+                if (SingletonMacro.has(ct)) {
+                    modify = true;
+                    var singleton = new SingletonMacro(ct, fields);
+                    fields = singleton.apply();
+                }
                 processed.set(localName, true);
                 modify ? fields : null;
             default: null;