Move default rewriter to packaged data

pyrs/pyrs/passes.py

@@ -1,34 +1,33 @@
 from pathlib import Path
+from typing import Optional
+import pkg_resources
 
 from pytket import Circuit
 from pytket.passes import CustomPass
 from pyrs.pyrs import passes, optimiser
 
 
 def taso_pass(
-    rewriter_dir=None,
-    rewriter_file=None,
-    max_threads=None,
-    timeout=None,
-    log_dir=None,
-    rebase=None,
+    rewriter: Optional[Path] = None,
+    max_threads: Optional[int] = None,
+    timeout: Optional[int] = None,
+    log_dir: Optional[Path] = None,
+    rebase: Optional[bool] = None,
 ) -> CustomPass:
     """Construct a TASO pass.
 
-    A Taso optimiser may be specified using either `rewriter_dir` or `rewriter_file`.
-    If `rewriter_dir` is specified, the optimiser will be loaded from the file
-    `rewriter_dir/nam_6_3.rwr`. By default, will search for a rewritier in
-    the current directory. The rewriter must be precompiled.
+    The Taso optimiser requires a pre-compiled rewriter produced by the
+    `compile-rewriter <https://github.com/CQCL/tket2/tree/main/taso-optimiser>`_
+    utility. If `rewriter` is not specified, a default one will be used.
 
     The arguments `max_threads`, `timeout`, `log_dir` and `rebase` are optional
     and will be passed on to the TASO optimiser if provided."""
-    if rewriter_dir is None:
-        rewriter_dir = "."
-    if rewriter_file is None:
-        rewriter_file = Path(rewriter_dir) / "nam_6_3.rwr"
-    opt = optimiser.TasoOptimiser.load_precompiled(rewriter_file)
+    if rewriter is None:
+        rewriter = pkg_resources.resource_filename("pyrs", "data/nam_6_3.rwr")
+        print("Using default rewriter", rewriter)
+    opt = optimiser.TasoOptimiser.load_precompiled(rewriter)
 
-    def apply(circuit: Circuit):
+    def apply(circuit: Circuit) -> Circuit:
         """Apply TASO optimisation to the circuit."""
         return passes.taso_optimise(
             circuit,