dimensioned export (gwy, HDF5)

backend/exporters/scalar.py

@@ -0,0 +1,28 @@
+"""
+Exporter for FLOAT scalars (also handles Python int and numpy scalar types).
+"""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from backend.exporters._base import FormatSpec
+
+accepted_types: tuple[str, ...] = ("FLOAT",)
+
+FORMATS: dict[str, FormatSpec] = {
+    "TXT":  FormatSpec(ext=".txt",  round_trip=True, label="Text"),
+    "JSON": FormatSpec(ext=".json", round_trip=True, label="JSON"),
+}
+
+
+def save(path: Path, value: float, format_name: str, **_opts) -> None:
+    numeric = float(value)
+    if format_name == "TXT":
+        path.write_text(f"{numeric}\n", encoding="utf-8")
+        return
+    if format_name == "JSON":
+        path.write_text(json.dumps({"value": numeric}, indent=2), encoding="utf-8")
+        return
+    raise ValueError(f"Format {format_name!r} is not supported for scalar values.")