Add recursive nesting to HTML option table rendering

qiskit_ibm_runtime/options/options.py

@@ -13,8 +13,8 @@
 """Primitive options."""
 
 from abc import abstractmethod
-from typing import Optional, Union, ClassVar, Any
-from dataclasses import dataclass, fields, field, asdict
+from typing import Iterable, Optional, Tuple, Union, ClassVar, Any
+from dataclasses import dataclass, fields, field, asdict, is_dataclass
 import copy
 import warnings
 
@@ -39,6 +39,43 @@
 from ..runtime_options import RuntimeOptions
 
 
+def _make_data_row(indent: int, name: str, value: Any, is_section: bool) -> Iterable[str]:
+    """Yield HTML table rows to format an options entry."""
+    tag = "th" if is_section else "td"
+
+    weight = " font-weight: bold;" if is_section else ""
+    style = f"style='text-align: left; vertical-align: top;{weight}'"
+
+    marker = "▸" if is_section else ""
+    spacer_style = "display: inline-block; text-align: right; margin-right: 10px;"
+    spacer = f"<div style='width: {20*(1 + indent)}px; {spacer_style}'>{marker}</div>"
+
+    yield "  <tr>"
+    yield f"    <{tag} {style}>{spacer}{name}</{tag}>"
+    yield f"    <{tag} {style}>{type(value).__name__ if is_section else repr(value)}</{tag}>"
+    yield "  </tr>"
+
+
+def _iter_all_fields(
+    data_cls: Any, indent: int = 0, dict_form: Union[dict, None] = None
+) -> Iterable[Tuple[int, str, Any, bool]]:
+    """Recursively iterate over a dataclass, yielding (indent, name, value, is_dataclass) fields."""
+    # we pass dict_form through recursion simply to avoid calling asdict() more than once
+    dict_form = dict_form or asdict(data_cls)
+
+    suboptions = []
+    for name, val in dict_form.items():
+        if is_dataclass(subopt := getattr(data_cls, name)):
+            suboptions.append((name, subopt))
+        elif name != "_VERSION":
+            yield (indent, name, val, False)
+
+    # put all of the nested options at the bottom
+    for name, subopt in suboptions:
+        yield (indent, name, subopt, True)
+        yield from _iter_all_fields(subopt, indent + 1, dict_form[name])
+
+
 @dataclass
 class BaseOptions:
     """Base options class."""
@@ -74,18 +111,11 @@ def _get_runtime_options(options: dict) -> dict:
 
     def _repr_html_(self) -> str:
         """Return a string that formats this instance as an HTML table."""
-        html_str = "<table style='font-size: 14px; width: 300px;'>"
-        for key, value in asdict(self).items():
-            if isinstance(value, dict):
-                html_str += f"<tr><th style='text-align: left;'>{key}</th><td></td></tr>"
-                for subkey, subvalue in value.items():
-                    html_str += (
-                        f"<tr><td style='text-align: left; padding-left: 20px;'>{subkey}</td>"
-                        f"<td>{subvalue}</td></tr>"
-                    )
-            else:
-                html_str += f"<tr><th style='text-align: left;'>{key}</th><td>{value}</td></tr>"
-        return html_str + "</table>"
+        table_html = [f"<pre>{type(self).__name__}<{hex(id(self))}></pre>", "<table>"]
+        for row in _iter_all_fields(self):
+            table_html.extend(_make_data_row(*row))
+        table_html.append("</table>")
+        return "\n".join(table_html)
 
 
 @primitive_dataclass