XIR converter (#643)

* add converters

* update io

* add and refactor io tests

* add xir to requirements

* use quantum-xir

* run format

* add tdm converters

* minor updates

* refactor io

* fix tdm

* fix other workaround

* fix tests

* make format

* switch to use constants

* install correct xir branch for tests to pass

* make format

* test updating setup

* revert to released xir

* update tests

* Apply suggestions from code review

Co-authored-by: Mikhail Andrenkov <Mandrenkov@users.noreply.github.com>
Co-authored-by: Tom Bromley <49409390+trbromley@users.noreply.github.com>

* suggestions from code review

* Apply suggestions from code review

Co-authored-by: Mikhail Andrenkov <Mandrenkov@users.noreply.github.com>

* fixes to tests

* move generate_code to utils

* fixes from code review

* Update setup.py

Co-authored-by: Tom Bromley <49409390+trbromley@users.noreply.github.com>

* update name to _name_

* Apply suggestions from code review

Co-authored-by: Mikhail Andrenkov <Mandrenkov@users.noreply.github.com>

* add aubergine

* make format

* fix typing for docs

* fix listr

* add test

* remove type hint to test

* add changelog

* Apply suggestions from code review

Co-authored-by: Mikhail Andrenkov <Mandrenkov@users.noreply.github.com>

* update test

* add default eng in generate_code

* fix tests

* add to tests

Co-authored-by: Mikhail Andrenkov <Mandrenkov@users.noreply.github.com>
Co-authored-by: Tom Bromley <49409390+trbromley@users.noreply.github.com>

.github/CHANGELOG.md

@@ -9,6 +9,34 @@
   has not previously been set.
   [(#663)](https://github.com/XanaduAI/strawberryfields/pull/663)
 
+* Functions are now available to convert between XIR and Strawberry Fields programs.
+  [(#643)](https://github.com/XanaduAI/strawberryfields/pull/643)
+
+  For example,
+
+  ```python
+  prog = sf.Program(3)
+  eng = sf.Engine("gaussian")
+
+  with prog.context as q:
+      ops.Sgate(0, 0) | q[0]
+      ops.Sgate(1, 0) | q[1]
+      ops.BSgate(0.45, 0.0) | (q[0], q[2])
+      ops.MeasureFock() | q[0]
+
+  xir_prog = sf.io.to_xir(prog)
+  ```
+
+  resulting in the following XIR script
+
+  ```pycon
+  >>> print(xir_prog.serialize())
+  Sgate(0, 0) | [0];
+  Sgate(1, 0) | [1];
+  BSgate(0.45, 0.0) | [0, 2];
+  MeasureFock | [0];
+  ```
+
 <h3>Breaking Changes</h3>
 
 <h3>Bug fixes</h3>

requirements.txt

@@ -14,4 +14,5 @@ thewalrus==0.17.0
 toml==0.10.2
 typing-extensions==3.7.4
 urllib3==1.25.8
+quantum-xir==0.1.1
 xanadu-cloud-client==0.1.1

setup.py

@@ -31,6 +31,7 @@
     "thewalrus>=0.17.0",
     "toml",
     "urllib3>=1.25.3",
+    "quantum-xir>=0.1.1",
     "xanadu-cloud-client>=0.1.1",
 ]