gen: compile time for (methods and fields) (#5957)

examples/compiletime/compile-time-for.v

@@ -0,0 +1,45 @@
+module main
+
+struct App {
+	test string [test]
+mut:
+	a    string
+}
+
+fn main() {
+	println('All functions')
+	$for method in App.methods {
+		$if method.@type is int {
+			println('hi')
+		}
+		println('$method.name.len')
+		println('$method.name.str')
+		println('Method: $method.name')
+		println('Attributes: $method.attrs')
+		println('Return type: $method.ret_type')
+	}
+	println('All integer functions')
+	$for method in App.methods {
+		println('Method: $method.name')
+		println('Attributes: $method.attrs')
+	}
+	$for field in App.fields {
+		$if field.@type is string {
+			println(field)
+		}
+	}
+}
+
+fn (mut app App) method_one() {
+}
+
+fn (mut app App) method_two() {
+}
+
+fn (mut app App) method_three() int {
+	return 0
+}
+
+fn (mut app App) method_four() int {
+	return 1
+}