diff --git a/packages/ludic.ui/backend.ludic b/packages/ludic.ui/backend.ludic
index 1fc7bc7f..309256c3 100644
--- a/packages/ludic.ui/backend.ludic
+++ b/packages/ludic.ui/backend.ludic
@@ -36,6 +36,9 @@ export state UiState {
   pl_cur: UiPool = null
   mm: UiMemo = null                      # memo.ludic: splits, gradients and keys by their text
   mm_ints: []string = null
+  mm_ivals: []Val = null
+  ev_depth: int = 0                      # eval.ludic: a call's arguments, in lists kept one a depth
+  ev_args: []Val = new []Val
   ly_depth: int = 0                      # layout_run.ludic: the lists a line lays out with, one a depth
   ly_sizes: [][]float = new [][]float
   ly_frozen: [][]bool = new [][]bool
diff --git a/packages/ludic.ui/build.ludic b/packages/ludic.ui/build.ludic
index 7ff8d45c..d2e24b37 100644
--- a/packages/ludic.ui/build.ludic
+++ b/packages/ludic.ui/build.ludic
@@ -49,7 +49,7 @@ function bd_each(ui_st: mut UiState, k: UiTpl, e: UiEnv, key: string, out: []UiN
   for j in 0 .. Value.count(list) {
     let le = env_new(ui_st, e)
     env_bind(le, as_name, Value.at(list, j))
-    env_bind(le, at_name, Value.int(j))
+    env_bind(le, at_name, mm_ival(ui_st, j))
     var id = mm_int(ui_st, j)
     if by != null { id = ui_eval_text(ui_st, by, le) }
     bd_kids(ui_st, k.kids, le, mm_join(ui_st, key, "#", id), out)
diff --git a/packages/ludic.ui/build_class.ludic b/packages/ludic.ui/build_class.ludic
index 641720a5..b4603e57 100644
--- a/packages/ludic.ui/build_class.ludic
+++ b/packages/ludic.ui/build_class.ludic
@@ -5,7 +5,9 @@ function bd_class(ui_st: mut UiState, k: UiTpl, e: UiEnv, key: string, out: []Ui
   let cls = k.cls
   uc_load(ui_st, cls)
   let it = in_get(ui_st, key, cls)
-  let props = Value.object()
+  if it.props == null { it.props = Value.object() }
+  let props = it.props
+  Value.clear(props)
   for i in 0 .. len(k.keys) {
     let a = k.keys[i]
     if a != "class" and a != "style" and a != "id" { Value.put(props, a, ui_eval(ui_st, k.vals[i], e)) }
diff --git a/packages/ludic.ui/elem.ludic b/packages/ludic.ui/elem.ludic
index fb1b32c0..cbaf014c 100644
--- a/packages/ludic.ui/elem.ludic
+++ b/packages/ludic.ui/elem.ludic
@@ -55,7 +55,7 @@ function el_text(ui_st: mut UiState, n: UiNode, s: string) -> void {
 function el_keep(ui_st: mut UiState, n: UiNode, key: string, v: Val) -> void {
   let s = vl_text_u(ui_st, v)
   if key == "id" { n.id = s } else if key == "class" {
-    let parts = lss_split(s, 32)
+    let parts = mm_split(ui_st, s, 32)
     for i in 0 .. len(parts) {
       if len(parts[i]) > 0 { push(n.classes, parts[i]) }
     }
diff --git a/packages/ludic.ui/eval.ludic b/packages/ludic.ui/eval.ludic
index 9b88cf47..c488dc69 100644
--- a/packages/ludic.ui/eval.ludic
+++ b/packages/ludic.ui/eval.ludic
@@ -34,8 +34,18 @@ function ui_eval(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> Val {
 }
 # a call: len() and range() are the template's own, anything else is the view's
 function ev_call(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> Val {
-  let args = Value.list()
+  let depth = ui_st.ev_depth
+  while len(ui_st.ev_args) <= depth { push(ui_st.ev_args, Value.list()) }
+  let args = ui_st.ev_args[depth]
+  Value.clear(args)
+  ui_st.ev_depth = depth + 1
   for i in 0 .. len(x.args) { Value.add(args, ui_eval(ui_st, x.args[i], e)) }
+  let r = ev_call_with(ui_st, x, e, args)
+  ui_st.ev_depth = depth
+  return r
+}
+# the call itself, its arguments evaluated; a callee reads them and keeps none
+function ev_call_with(ui_st: mut UiState, x: UiExpr, e: UiEnv, args: Val) -> Val {
   if x.s == "len" and len(x.args) == 1 { return Value.int(Value.count(Value.at(args, 0))) }
   if x.s == "range" and len(x.args) == 1 {
     let out = Value.list()
diff --git a/packages/ludic.ui/instance.ludic b/packages/ludic.ui/instance.ludic
index 57bbec41..30bec83e 100644
--- a/packages/ludic.ui/instance.ludic
+++ b/packages/ludic.ui/instance.ludic
@@ -5,6 +5,7 @@ property UiInst {
   cls: UiClass = null
   ptr: pointer = null
   seen: int = 0
+  props: Val = null             # its props, filled again each frame into the same object
 }
 function in_get(ui_st: mut UiState, key: string, k: UiClass) -> UiInst {
   for i in 0 .. len(ui_st.in_list) {
diff --git a/packages/ludic.ui/memo_join.ludic b/packages/ludic.ui/memo_join.ludic
index c429cff4..6031be13 100644
--- a/packages/ludic.ui/memo_join.ludic
+++ b/packages/ludic.ui/memo_join.ludic
@@ -40,3 +40,12 @@ function mm_int(ui_st: mut UiState, i: int) -> string {
   }
   return ui_st.mm_ints[i]
 }
+# a small whole number as a Value, made once and shared: read it, never change it (a loop's index)
+function mm_ival(ui_st: mut UiState, i: int) -> Val {
+  if i < 0 or i >= 1024 { return Value.int(i) }
+  if ui_st.mm_ivals == null {
+    ui_st.mm_ivals = new []Val
+    for k in 0 .. 1024 { push(ui_st.mm_ivals, Value.int(k)) }
+  }
+  return ui_st.mm_ivals[i]
+}
diff --git a/packages/ludic.ui/native.ludic b/packages/ludic.ui/native.ludic
index 6c22b246..374878ab 100644
--- a/packages/ludic.ui/native.ludic
+++ b/packages/ludic.ui/native.ludic
@@ -78,7 +78,13 @@ export function ui_attr(n: UiNode, key: string) -> Val {
   }
   return Value.null()
 }
-export function ui_attr_text(n: UiNode, key: string) -> string { return vl_text(ui_attr(n, key)) }
+export function ui_attr_text(n: UiNode, key: string) -> string {
+  if n.akeys == null { return "" }
+  for i in 0 .. len(n.akeys) {
+    if n.akeys[i] == key { return vl_text(n.vals[i]) }
+  }
+  return ""
+}
 # a boolean attribute: present with no value is true, as HTML's are (<button autofocus>)
 export function ui_attr_on(n: UiNode, key: string) -> bool {
   if n.akeys == null { return false }
diff --git a/runtime/native/namespaces.ludic b/runtime/native/namespaces.ludic
index 3f8627e4..5f622eb4 100644
--- a/runtime/native/namespaces.ludic
+++ b/runtime/native/namespaces.ludic
@@ -479,6 +479,7 @@ namespace Value {
   alias as_float(value) = value_as_float
   alias as_str(value) = value_as_str
   alias free(value) = value_free
+  alias clear(value) = value_clear
 }
 namespace Json {
   alias encode(value) = json_encode
diff --git a/runtime/native/value.ludic b/runtime/native/value.ludic
index db160c12..8021d4a9 100644
--- a/runtime/native/value.ludic
+++ b/runtime/native/value.ludic
@@ -69,6 +69,12 @@ function value_put(obj: Val, key: pointer, item: Val) -> Val {
 # --- accessors --------------------------------------------------------------
 function value_kind(v: Val) -> int { return v.tag }
 function value_count(v: Val) -> int { return value_n(v) }
+# a list or an object emptied in place, its room kept - for one filled again every frame
+function value_clear(v: Val) -> void {
+  if v.kids == null { return }
+  List.clear(v.kids)
+  List.clear(v.keys)
+}
 function value_as_int(v: Val) -> int {
   if v.tag == 7 { return int(float_from_bits(v.num)) }
   return v.num