attributes: @Node(field), @Derived, @Text, @Multiline and @Key on a field, into the schema - @Node's field must be @Asset("gltf") or an @Ref to a registry whose record has exactly one, every failure reported; reseeded

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

LANGUAGE.md

@@ -639,14 +639,19 @@ property Tool {
   @Range(0, 20.5) @Unit("kg") weight: float = 1.0
   @Asset("gltf") model: string = ""        # a file of that kind (any string)
   @Color tint: int = 0
+  @Node(model) grip: string = ""           # a node inside the glTF that `model` names
+  @Derived reach: float = 0.0              # worked out at boot: anything written is overwritten
+  @Text @Multiline blurb: string = ""      # read by the player (so translated), and prose
+  @Key bind: int = 0                       # a key code
 }
 @AppendOnly @ByKey
 registry Tools of Tool as TL from "data/tools.lres"
 ```
 
-They change nothing the program does. One is checked: `@Ref` must name a registry the program
-declares, and a field whose `@Ref` names none is an error naming the field and the registry (every
-such field is reported, not only the first).
+They change nothing the program does. Two are checked, and every field that fails is reported, not
+only the first: `@Ref` must name a registry the program declares, and `@Node(f)` must name a field
+`f` of the same record that is either `@Asset("gltf")` or an `@Ref` to a registry whose record has
+exactly one `@Asset("gltf")` field (the model is then the referenced row's).
 
 `ludicc app.ludic --emit-schema out.json` (or `ludic schema [file] [-o out.json]`) writes what the
 compiler resolved, once the types are checked and every open registry has its entries, as one JSON

changes/editor-schema.md

@@ -8,7 +8,8 @@ prefix, resource file, openness and its entries in their final order after the o
 which entries in); every const; and every function a `fn` value can name, with the `fn_type` a field sees (its states stripped).
 Deterministic, `"schema_version": 1`. Fields and registries carry editor attributes on the existing
 `@` syntax - `@Ref(Registry)`, `@OneOf(PREFIX_)`, `@Range(lo, hi)`, `@Unit("m/s")`, `@Asset("gltf")`,
-`@Color`, and `@AppendOnly` / `@ByKey` on a registry - which change nothing but go into the schema;
-`@Ref` naming no registry is an error. A field may now carry several attributes. `ludicc --check
+`@Color`, `@Node(field)`, `@Derived`, `@Text`, `@Multiline`, `@Key`, and `@AppendOnly` / `@ByKey` on
+a registry - which change nothing but go into the schema; `@Ref` naming no registry is an error, and
+so is `@Node` naming a field that is not a glTF (`@Asset("gltf")`, or an `@Ref` to one). A field may now carry several attributes. `ludicc --check
 --diagnostics=json` (`ludic build --check --diagnostics=json`) prints every error as one JSON array
 of `{file, line, col, severity, message}` on stdout; tokens and nodes now know their column.

examples/lang/attributes.ludic

@@ -1,8 +1,8 @@
 # attributes.ludic — editor metadata on the @-syntax: which registry a field indexes, which constants
 # it takes, its range, its unit, the kind of file it names, that it is a colour, and a registry's own
 # rules (append only, saved by key). None of them changes what the program does: `ludicc
-# --emit-schema` carries them to an editor with every record, registry entry and const. One is
-# checked - @Ref must name a registry that exists.
+# --emit-schema` carries them to an editor with every record, registry entry and const. Two are
+# checked - @Ref must name a registry that exists, and @Node a field of its record naming a glTF.
 #
 # Running it prints:  2 1 Lantern 2
 program Attributes {
@@ -26,9 +26,18 @@ program Attributes {
     model: string = ""                         # its model, under assets/kit
     @Color tint: int = 16777215
     @OneOf(VD_) stocked_at: int = VD_STORE
+    @Node(model) grip: string = "grip"        # where a hand holds it, a node in that model
+    @Derived reach: float = 0.0                # worked out at boot from the model
+    @Text @Multiline blurb: string = ""        # what the shop says about it
+    @Key bind: int = 0                         # the key that takes it in hand
   }
   @AppendOnly
   registry Tools of Tool as TL from "data/attr_tools.lres"
+  # a tool hung on the camp's rack: which, and from which node of ITS model
+  property RackSlot {
+    @Ref(Tools) tool: int = 0
+    @Node(tool) hook: string = "grip"
+  }
   const CAMP_TOOLS: int = 2 * VD_COUNT         # how many a camp can carry
   # the tool a new camp starts with
   function first_tool() -> string { return Tools[0].name }

examples/rejected/node_bad.ludic

@@ -0,0 +1,18 @@
+# attributes: @Node names a field of its record that names a glTF - `handle` names no field, `tag`
+# is a plain string, and `kit` refers to a registry whose record has two models (all three are reported)
+program R {
+  property Kit {
+    key: string = ""
+    @Asset("gltf") body: string = ""
+    @Asset("gltf") lod: string = ""
+  }
+  registry Kits of Kit
+  property Tool {
+    tag: string = ""
+    @Ref(Kits) kit: int = 0
+    @Node(handle) grip: string = ""
+    @Node(tag) tip: string = ""
+    @Node(kit) hook: string = ""
+  }
+  entry { print(KITS_COUNT) }
+}

selfhost/frontend/attrs.ludic

@@ -8,10 +8,15 @@
 #     @Unit("m/s") speed: float = 0.0
 #     @Asset("gltf") model: string = ""        # a file of that kind
 #     @Color tint: int = 0
+#     @Node(model) grip: string = ""           # a node inside the glTF the field `model` names
+#     @Derived reach: float = 0.0              # worked out at boot: anything written is overwritten
+#     @Text @Multiline blurb: string = ""      # read by the player, so translated; prose
+#     @Key bind: int = 0                       # a key code
 #   }
 #   @AppendOnly @ByKey registry Items of Item as IT from "items.lres"
 #
-# They change nothing the program does. One is checked: @Ref must name a registry that exists. A
+# They change nothing the program does. Two are checked: @Ref must name a registry that exists, and
+# @Node a field of its record that names a glTF (attrs_node.ludic). A
 # field's or a registry's attributes are a group (Node.at, g_rg_at): a run of names, each with its
 # arguments as JSON values - an identifier or a string as a string, a number as written.
 var g_at_start: []int = new []int            # a group's first attribute ...
@@ -92,19 +97,24 @@ function at_lead0(raw: pointer) -> pointer {
 }
 # the editor attributes a field may carry, and what each takes
 function at_field_known(a: pointer) -> bool {
-  return (a == "Ref") or (a == "OneOf") or (a == "Range") or (a == "Unit") or (a == "Asset") or (a == "Color")
+  if (a == "Ref") or (a == "OneOf") or (a == "Range") or (a == "Unit") or (a == "Asset") or (a == "Color") { return true }
+  return (a == "Node") or at_flag(a)
+}
+# the attributes that take nothing: they say what a field is
+function at_flag(a: pointer) -> bool {
+  return (a == "Color") or (a == "Derived") or (a == "Text") or (a == "Multiline") or (a == "Key")
 }
 # one field attribute, its '@' and name already read: its arguments, checked for shape, into group g
 function at_field(g: int, a: pointer) -> void {
   let args = at_args()
   let n = g_at_argn
-  if (a == "Ref") or (a == "OneOf") {
+  if (a == "Ref") or (a == "OneOf") or (a == "Node") {
     if n != 1 or toks[pi - 2].kind != TK_ID { perr(`@{a} takes one name: @{a}(Items)`) }
   }
   if (a == "Range") and n != 2 { perr("@Range takes the least and the most: @Range(0, 1.5)") }
   if (a == "Range") and not g_at_allnum { perr("@Range takes two numbers: @Range(0, 1.5)") }
   if ((a == "Unit") or (a == "Asset")) and (n != 1 or toks[pi - 2].kind != TK_STR) { perr(`@{a} takes one string: @{a}("m/s")`) }
-  if (a == "Color") and n != 0 { perr("@Color takes nothing") }
+  if at_flag(a) and n != 0 { perr(`@{a} takes nothing`) }
   at_push(g, a, args, g_at_arg0, n)
 }
 # a field's group, made the first time it needs one
@@ -135,7 +145,8 @@ function at_registry_take() -> int {
   g_at_decl = new []pointer
   return g
 }
-# once every registry is declared: each @Ref names one, or the build stops with every one that does not
+# once every registry is declared: each @Ref names one and each @Node a glTF field, or the build
+# stops with every one that does not
 function at_check_refs() -> void {
   var i = 0
   while i < len(prog) {
@@ -159,6 +170,7 @@ function at_check_field(d: Node, f: Node) -> void {
     if (g_at_name[j] == "Ref") and reg_find(g_at_first[j]) < 0 {
       perr_at(f.file, f.line, f.col, `field {d.s}.{f.s}: @Ref({g_at_first[j]}) names no registry - there is no registry {g_at_first[j]}`)
     }
+    if g_at_name[j] == "Node" { at_check_node(d, f, g_at_first[j]) }
     j += 1
   }
 }

selfhost/frontend/attrs_node.ludic

@@ -0,0 +1,69 @@
+# attrs_node.ludic — @Node(model): a string naming a node inside the glTF another field of the same
+# record names. That field is @Asset("gltf") itself, or an @Ref(R) whose record has exactly one
+# @Asset("gltf") field (the model is found through the row). Anything else is an error naming it.
+
+# the field of record d called name, or null
+function at_field_of(d: Node, name: pointer) -> Node {
+  var k = 0
+  while k < len(d.kids) {
+    if d.kids[k].s != null and vis_plain(d.kids[k].s) == name { return d.kids[k] }
+    k += 1
+  }
+  return null
+}
+# field f's argument to attribute a as written, or null when f does not carry it
+function at_arg_of(f: Node, a: pointer) -> pointer {
+  if f.at < 0 { return null }
+  var j = g_at_start[f.at]
+  while j < g_at_start[f.at] + g_at_count[f.at] {
+    if g_at_name[j] == a { return g_at_first[j] }
+    j += 1
+  }
+  return null
+}
+function at_is_gltf(f: Node) -> bool {
+  let a = at_arg_of(f, "Asset")
+  return a != null and a == "gltf"
+}
+# the record called name (a property or record), or null
+function at_record(name: pointer) -> Node {
+  let plain = vis_plain(name)
+  var i = 0
+  while i < len(prog) {
+    if prog[i].kind == N_COMP and prog[i].s != null and vis_plain(prog[i].s) == plain { return prog[i] }
+    i += 1
+  }
+  return null
+}
+# how many @Asset("gltf") fields record r carries
+function at_gltf_count(r: Node) -> int {
+  var n = 0
+  var k = 0
+  while k < len(r.kids) {
+    if at_is_gltf(r.kids[k]) { n += 1 }
+    k += 1
+  }
+  return n
+}
+function at_check_node(d: Node, f: Node, target: pointer) -> void {
+  let where = `field {d.s}.{f.s}: @Node({target})`
+  let t = at_field_of(d, target)
+  if t == null {
+    perr_at(f.file, f.line, f.col, `{where} names no field - {d.s} has no field {target}`)
+    return
+  }
+  if at_is_gltf(t) { return }
+  let reg = at_arg_of(t, "Ref")
+  if reg == null {
+    perr_at(f.file, f.line, f.col, `{where}: {target} is neither @Asset("gltf") nor an @Ref to a registry of models`)
+    return
+  }
+  let r = reg_find(reg)
+  if r < 0 { return }                                  # @Ref's own check says so
+  let rec = at_record(g_rg_type[r])
+  var n = 0
+  if rec != null { n = at_gltf_count(rec) }
+  if n != 1 {
+    perr_at(f.file, f.line, f.col, `{where}: {target} is an @Ref({reg}), and its record {g_rg_type[r]} has {n} @Asset("gltf") fields, not one`)
+  }
+}

tools/ludic-cli/selfhost.ludic

@@ -33,6 +33,7 @@ function selfhost_frags() -> []pointer {
   push(f, "selfhost/frontend/registry_finish.ludic")
   push(f, "selfhost/frontend/registry_open.ludic")
   push(f, "selfhost/frontend/attrs.ludic")
+  push(f, "selfhost/frontend/attrs_node.ludic")
   push(f, "selfhost/frontend/resource.ludic")
   push(f, "selfhost/frontend/defaults.ludic")
   push(f, "selfhost/frontend/view.ludic")

tools/ludic-cli/test.ludic

@@ -1200,6 +1200,7 @@ function cmd_dev_test() -> int {
   reject_count("rejected/every_error", 3, "every type error in a program is reported at once, not only the first")
   diag_json_case("rejected/every_error", 3, "\"line\": 8, \"col\": 15, \"severity\": \"error\", \"message\": \"half takes 1 argument(s) and this call gives 2\"", "--diagnostics=json: every type error as {file, line, col, severity, message}")
   diag_json_case("rejected/ref_unknown", 2, "@Ref(Shops) names no registry", "--diagnostics=json: every @Ref that names no registry")
+  diag_json_case("rejected/node_bad", 3, "its record Kit has 2 @Asset(", "--diagnostics=json: every @Node that names no model field")
   feat_case("lang/generics", "", "7 Crater Lake a 2 west 7 0.75 2.5 1", "generics.ludic (L5: generic records and functions, nested instances, fn-typed parameters and fields, inference from the result's slot)")
   reject_case("rejected/generic_unbound", "cannot tell what T is in this call to pool_new", "a call whose type arguments nothing decides is refused")
   reject_case("rejected/generic_mismatch", "words wants a Pool<string> and this is a Pool<int>", "two instances of one generic are two types")
@@ -1232,9 +1233,11 @@ function cmd_dev_test() -> int {
   reject_case("rejected/registry_unknown", "there is no registry Tables", "a def names a registry that exists")
   feat_case("lang/attributes", "", "2 1 Lantern 2", "attributes.ludic (editor attributes: @Ref, @OneOf, @Range, @Unit, @Asset, @Color, @AppendOnly, @ByKey - no effect on the program)")
   reject_case("rejected/ref_unknown", "field Tool.seller: @Ref(Vendorz) names no registry", "@Ref names a registry that exists")
+  reject_case("rejected/node_bad", "field Tool.grip: @Node(handle) names no field", "@Node names a field of its record")
   schema_case("lang/attributes", "{\"name\": \"weight\", \"type\": \"float\", \"default\": \"1.0\", \"file\": \"examples/lang/attributes.ludic\", \"line\": 24, \"col\": 33, \"attributes\": [{\"name\": \"Range\", \"args\": [0, 20.5]}, {\"name\": \"Unit\", \"args\": [\"kg\"]}]", "--emit-schema: a field's type, default, place and attributes")
   schema_case("lang/attributes", "{\"key\": \"lantern\", \"constant\": \"TL_LANTERN\", \"index\": 1, \"file\": \"examples/lang/data/attr_tools.lres\", \"line\": 3, \"col\": 1", "--emit-schema: a resource entry's constant, index and place")
   schema_case("lang/attributes", "\"fn_type\": \"fn(Tool,int)->float\", \"params\": [\"Tool\", \"int\"]", "--emit-schema: a function with arguments, its fn_type spelled as a field's")
+  schema_case("lang/attributes", "{\"name\": \"Node\", \"args\": [\"tool\"]}", "--emit-schema: @Node and the field it reads its model from")
   reject_case("rejected/registry_twice", "def Furnishings crate is declared twice", "a registry's key is declared once")
   reject_case("rejected/registry_field", "Furnishing has no field colour", "a def's fields are the record's")
   feat_case("modules/open_registry", "", "clock animals weather / 2 2 3", "open_registry.ludic (L8+L3: an open registry takes other modules' defs; its own entries first, then by module name)")