Rust: fix generated hierarchy

Author: Paolo Tranquilli

misc/codegen/generators/rustgen.py

@@ -80,7 +80,7 @@ def _get_class(self, name: str) -> rust.Class:
                 if "rust_skip" not in p.pragmas and not p.synth
             ] if not cls.derived else [],
             ancestors=sorted(set(a.name for a in _get_ancestors(cls, self._classmap))),
-            table_name=inflection.tableize(cls.name),
+            entry_table=inflection.tableize(cls.name) if not cls.derived else None,
         )
 
     def get_classes(self):

misc/codegen/lib/rust.py

@@ -110,13 +110,19 @@ def is_label(self):
 @dataclasses.dataclass
 class Class:
     name: str
-    table_name: str | None = None
+    entry_table: str | None = None
     fields: list[Field] = dataclasses.field(default_factory=list)
     ancestors: list[str] = dataclasses.field(default_factory=list)
 
     @property
-    def single_field_entries(self):
-        ret = {self.table_name: []}
+    def is_entry(self) -> bool:
+        return bool(self.entry_table)
+
+    @property
+    def single_field_entries(self) -> dict[str, list[dict]]:
+        ret = {}
+        if self.is_entry:
+            ret[self.entry_table] = []
         for f in self.fields:
             if f.is_single:
                 ret.setdefault(f.table_name, []).append(f)

misc/codegen/templates/rust_classes.mustache

@@ -5,7 +5,7 @@
 use crate::trap;
 {{#classes}}
 
-{{#table_name}}
+{{#is_entry}}
 #[derive(Debug)]
 pub struct {{name}} {
     pub id: trap::TrapId<{{name}}>,
@@ -15,15 +15,13 @@ pub struct {{name}} {
 }
 
 impl trap::TrapEntry for {{name}} {
-    fn class_name() -> &'static str { "{{name}}" }
-
     fn extract_id(&mut self) -> trap::TrapId<Self> {
         std::mem::replace(&mut self.id, trap::TrapId::Star)
     }
 
     fn emit(self, id: trap::Label<Self>, out: &mut trap::Writer) {
         {{#single_field_entries}}
-        out.add_tuple("{{table_name}}", vec![id.into(){{#fields}}, self.{{field_name}}.into(){{/fields}}]);
+        out.add_tuple("{{entry_table}}", vec![id.into(){{#fields}}, self.{{field_name}}.into(){{/fields}}]);
         {{/single_field_entries}}
         {{#fields}}
         {{#is_predicate}}
@@ -53,13 +51,18 @@ impl trap::TrapEntry for {{name}} {
         {{/fields}}
     }
 }
-{{/table_name}}
-{{^table_name}}
+{{/is_entry}}
+{{^is_entry}}
 {{! virtual class, make it unbuildable }}
+#[derive(Debug)]
 pub struct {{name}} {
-    unused: ()
+    _unused: ()
+}
+{{/is_entry}}
+
+impl trap::TrapClass for {{name}} {
+    fn class_name() -> &'static str { "{{name}}" }
 }
-{{/table_name}}
 {{#ancestors}}
 
 impl From<trap::Label<{{name}}>> for trap::Label<{{.}}> {