Initial approach outline

pytket/phir/api.py

@@ -0,0 +1,22 @@
+from pytket.circuit import Circuit
+
+from .sharding.sharder import Sharder
+
+
+def pytket_to_phir(
+    circuit: Circuit,
+) -> str:
+    """Converts a pytket circuit into its PHIR representation
+
+    :param circuit: Circuit object to be converted
+    """
+
+    # TODO: Process circuit according to desired machine architecture
+
+    sharder = Sharder(circuit)
+    shards = sharder.shard()  # noqa: F841
+
+    # TODO: Pass shards[] into placement, routing, etc
+    # TODO: Convert to PHIR JSON spec and return
+
+    return "{ phir json, someday }"