From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 24 Nov 2019 00:50:18 +0000 (+0000)
Subject: catacomb/__init__.py, mp.c: Use implicit-conversion rules for rationals.
X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb-python/commitdiff_plain/1e8aaf8b7069139bdbd802e1d419cd10141bebd5

catacomb/__init__.py, mp.c: Use implicit-conversion rules for rationals.

Export the implicit conversions for `MP' and `GF' to Python, and use
them in the `BaseRat' constructor.
---

diff --git a/catacomb/__init__.py b/catacomb/__init__.py
index dc5ecbb..725f6d2 100644
--- a/catacomb/__init__.py
+++ b/catacomb/__init__.py
@@ -275,7 +275,7 @@ def secret_unbox(k, n, c):
 class BaseRat (object):
   """Base class implementing fields of fractions over Euclidean domains."""
   def __new__(cls, a, b):
-    a, b = cls.RING(a), cls.RING(b)
+    a, b = cls.RING._implicit(a), cls.RING._implicit(b)
     q, r = divmod(a, b)
     if r == cls.ZERO: return q
     g = b.gcd(r)
diff --git a/mp.c b/mp.c
index ce04819..3abbcd5 100644
--- a/mp.c
+++ b/mp.c
@@ -603,6 +603,22 @@ end:
   return ((PyObject *)zz);
 }
 
+#define IMPLICIT(pre)							\
+  static PyObject *pre##meth__implicit(PyObject *me, PyObject *arg)	\
+  {									\
+    PyObject *x, *rc = 0;						\
+    mp *y = MP_NEW;							\
+    if (!PyArg_ParseTuple(arg, "O:_implicit", &x)) goto end;		\
+    y = implicit##pre(x);						\
+    if (!y) TYERR("can't convert implicitly to " #pre);			\
+    rc = pre##_pywrap(y);						\
+  end:									\
+    return (rc);							\
+  }
+IMPLICIT(mp)
+IMPLICIT(gf)
+#undef IMPLICIT
+
 Py_hash_t mphash(mp *x)
 {
   PyObject *l = mp_topylong(x);
@@ -931,6 +947,7 @@ static const PyMethodDef mp_pymethods[] = {
     "  Parse STR as a large integer, according to RADIX.  If RADIX is\n"
     "  zero, read a prefix from STR to decide radix: allow `0b' for binary,\n"
     "  `0' or `0o' for octal, `0x' for hex, or `R_' for other radix R.")
+  SMTH	(_implicit,	0)
   SMTH	(factorial,	"factorial(I) -> I!: compute factorial")
   SMTH	(fibonacci,	"fibonacci(I) -> F(I): compute Fibonacci number")
   SMTH	(loadl,		"loadl(STR) -> X: read little-endian bytes")
@@ -2123,6 +2140,7 @@ static const PyMethodDef gf_pymethods[] = {
     "  Parse STR as a binary polynomial, according to RADIX.  If RADIX is\n"
     "  zero, read a prefix from STR to decide radix: allow `0b' for binary,\n"
     "  `0' or `0o' for octal, `0x' for hex, or `R_' for other radix R.")
+  SMTH	(_implicit,	0)
   SMTH	(loadl,		"loadl(STR) -> X: read little-endian bytes")
   SMTH	(loadb,		"loadb(STR) -> X: read big-endian bytes")
   SMTH	(frombuf,	"frombuf(STR) -> (X, REST): read buffer format")
diff --git a/t/t-mp.py b/t/t-mp.py
index 24e80cd..2cba8ec 100644
--- a/t/t-mp.py
+++ b/t/t-mp.py
@@ -156,7 +156,7 @@ class TestMP (U.TestCase):
 
   def test_strconv(me):
     x, y = C.MP(169), "24"
-    for fn in [T.add, T.sub]:
+    for fn in [T.add, T.sub, T.div]:
       me.assertRaises(TypeError, fn, x, y)
       me.assertRaises(TypeError, fn, y, x)
     me.assertEqual(x*y, 169*"24")
diff --git a/t/t-rat.py b/t/t-rat.py
index 9fd15d4..a2198bd 100644
--- a/t/t-rat.py
+++ b/t/t-rat.py
@@ -68,11 +68,20 @@ class TestRat (U.TestCase):
     me.assertFalse(b/a > c/a)
     me.assertTrue(c/a > b/a)
 
+    ## Conversions from string.
+    me.assertRaises(TypeError, T.add, f, "3")
+
   def test_intrat(me):
     me.check_rat(C.IntRat)
 
-    ## Check string conversions.
+    ## Check interaction with floating point.
     u = C.MP(5)/C.MP(4)
+    me.assertEqual(type(u + 0.0), float)
+    me.assertEqual(u, 1.25)
+    me.assertTrue(u < 1.26)
+    me.assertTrue(u > 1.24)
+
+    ## Check string conversions.
     me.assertEqual(str(u), "5/4")
     me.assertEqual(repr(u), "IntRat(5, 4)")
 
@@ -81,6 +90,7 @@ class TestRat (U.TestCase):
 
     ## Check string conversions.
     u = C.GF(5)/C.GF(4)
+    me.assertRaises(TypeError, T.add, u, 0.0)
     me.assertEqual(str(u), "0x5/0x4")
     me.assertEqual(repr(u), "GFRat(0x5, 0x4)")