From 517c43fef22cd4ce22507b1e8da88997e40157ca Mon Sep 17 00:00:00 2001
From: Mark Yeatman <myeatman@theaiinstitute.com>
Date: Wed, 21 Feb 2024 13:15:06 -0500
Subject: [PATCH 1/2] Add code+test to make sure using 4x1 vector with v
 keyword argument works.

---
 spatialmath/quaternion.py | 5 +++++
 tests/test_quaternion.py  | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/spatialmath/quaternion.py b/spatialmath/quaternion.py
index be0ea2f0..fde1ab9d 100644
--- a/spatialmath/quaternion.py
+++ b/spatialmath/quaternion.py
@@ -979,6 +979,11 @@ def __init__(
         """
         super().__init__()
 
+        # handle: UnitQuaternion(v)`` constructs a unit quaternion with specified elements 
+        # from ``v`` which is a 4-vector given as a list, tuple, or ndarray(4)
+        if s is None and smb.isvector(v, 4):
+            v,s = (s,v)
+
         if v is None:
             # single argument
             if super().arghandler(s, check=check):
diff --git a/tests/test_quaternion.py b/tests/test_quaternion.py
index 0f2ac871..3c992512 100644
--- a/tests/test_quaternion.py
+++ b/tests/test_quaternion.py
@@ -70,6 +70,9 @@ def test_constructor(self):
         qcompare(UnitQuaternion(2, [0, 0, 0]), np.r_[1, 0, 0, 0])
         qcompare(UnitQuaternion(-2, [0, 0, 0]), np.r_[1, 0, 0, 0])
 
+        qcompare(UnitQuaternion([1, 2, 3, 4]), UnitQuaternion(v = [1, 2, 3, 4]))
+        qcompare(UnitQuaternion(s = 1, v = [2, 3, 4]), UnitQuaternion(v = [1, 2, 3, 4]))
+
         # from R
 
         qcompare(UnitQuaternion(np.eye(3)), [1, 0, 0, 0])

From 11564a92193dd771e41108007de65d065821a51d Mon Sep 17 00:00:00 2001
From: Mark Yeatman <myeatman@theaiinstitute.com>
Date: Wed, 21 Feb 2024 13:19:15 -0500
Subject: [PATCH 2/2] Propogate changes to "basic" quaternion as well

---
 spatialmath/quaternion.py | 3 +++
 tests/test_quaternion.py  | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/spatialmath/quaternion.py b/spatialmath/quaternion.py
index fde1ab9d..26d8093a 100644
--- a/spatialmath/quaternion.py
+++ b/spatialmath/quaternion.py
@@ -77,6 +77,9 @@ def __init__(self, s: Any = None, v=None, check: Optional[bool] = True):
         """
         super().__init__()
 
+        if s is None and smb.isvector(v, 4):
+            v,s = (s,v)
+
         if v is None:
             # single argument
             if super().arghandler(s, check=False):
diff --git a/tests/test_quaternion.py b/tests/test_quaternion.py
index 3c992512..791e27bf 100644
--- a/tests/test_quaternion.py
+++ b/tests/test_quaternion.py
@@ -756,6 +756,9 @@ def test_constructor(self):
         nt.assert_array_almost_equal(Quaternion(2, [0, 0, 0]).vec, [2, 0, 0, 0])
         nt.assert_array_almost_equal(Quaternion(-2, [0, 0, 0]).vec, [-2, 0, 0, 0])
 
+        qcompare(Quaternion([1, 2, 3, 4]), Quaternion(v = [1, 2, 3, 4]))
+        qcompare(Quaternion(s = 1, v = [2, 3, 4]), Quaternion(v = [1, 2, 3, 4]))
+
         # pure
         v = [5, 6, 7]
         nt.assert_array_almost_equal(