Merge pull request 'schemagen: keep null elements in arrays with nullable item types' (#8) from weaselbot/weaseljson:weaselbot/issue-5 into main

Reviewed-on: #8

contrib/schemagen/weaseljson_schemagen.py

@@ -718,6 +718,34 @@ namespace {ns} {{"""
             "  }"
         )
 
+    def _is_array_kind(self):
+        arrs = [n for n, _ in self.arr_types]
+        if not arrs:
+            return "  bool isArrayKind(Kind) const { return false; }"
+        cases = " ".join(f"case Kind::{n}:" for n in arrs)
+        return (
+            "  bool isArrayKind(Kind k) const {\n"
+            f"    switch (k) {{ {cases} return true; default: return false; }}\n"
+            "  }"
+        )
+
+    def _append_null(self):
+        lines = [
+            "  void appendNull(Frame &f) {",
+            "    switch (f.kind) {",
+        ]
+        for name, tarr in self.arr_types:
+            vectype = self.base_cpp(tarr)
+            lines.append(f"    case Kind::{name}: {{")
+            lines.append(f"      auto *v = ({vectype} *)f.dest;")
+            lines.append("      v->emplace_back();")
+            lines.append("      return;")
+            lines.append("    }")
+        lines.append("    default: return;")
+        lines.append("    }")
+        lines.append("  }")
+        return "\n".join(lines)
+
     def _is_strict(self):
         strict = [n for n, o in self.b.objects.items() if o.strict]
         if not strict:
@@ -992,6 +1020,10 @@ private:
     valueComplete();
   }}
 
+{self._is_array_kind()}
+
+{self._append_null()}
+
   void cbNull() {{
     if (error_) return;
     Frame &f = stack_.back();
@@ -999,6 +1031,7 @@ private:
     SlotInfo si = slotInfoG(f);
     if (si.cat == Cat::Skip) {{ valueComplete(); return; }}
     if (!si.nullable) {{ reject(); return; }}
+    if (isArrayKind(f.kind)) appendNull(f);  // keep null array elements
     valueComplete();  // leave optional empty / pointer null
   }}