Merge pull request #3 from ericvsmith/pprint

Initial version of !p with f-strings.

Author: warsaw

Include/ceval.h

@@ -125,13 +125,14 @@ PyAPI_FUNC(void) PyEval_ReleaseThread(PyThreadState *tstate);
                  }
 
 /* Masks and values used by FORMAT_VALUE opcode. */
-#define FVC_MASK      0x3
+#define FVC_MASK      0x7
 #define FVC_NONE      0x0
 #define FVC_STR       0x1
 #define FVC_REPR      0x2
 #define FVC_ASCII     0x3
-#define FVS_MASK      0x4
-#define FVS_HAVE_SPEC 0x4
+#define FVC_PRETTY    0x4
+#define FVS_MASK      0x8
+#define FVS_HAVE_SPEC 0x8
 
 #ifndef Py_LIMITED_API
 #  define Py_CPYTHON_CEVAL_H

Include/object.h

@@ -466,6 +466,7 @@ PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
 PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *);
+PyAPI_FUNC(PyObject *) PyObject_Pretty(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *);
 PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);
 PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);

Lib/test/test_fstring.py

@@ -1369,7 +1369,7 @@ def test_conversions(self):
         for conv_identifier in 'g', 'A', 'G', 'ä', 'ɐ':
             self.assertAllRaise(SyntaxError,
                                 "f-string: invalid conversion character %r: "
-                                "expected 's', 'r', or 'a'" % conv_identifier,
+                                "expected 's', 'r', 'a', or 'p'" % conv_identifier,
                                 ["f'{3!" + conv_identifier + "}'"])
 
         for conv_non_identifier in '3', '!':
@@ -1385,7 +1385,7 @@ def test_conversions(self):
 
         self.assertAllRaise(SyntaxError,
                             "f-string: invalid conversion character 'ss': "
-                            "expected 's', 'r', or 'a'",
+                            "expected 's', 'r', 'a', or 'p'",
                             ["f'{3!ss}'",
                              "f'{3!ss:}'",
                              "f'{3!ss:s}'",

Lib/test/test_print.py

@@ -239,6 +239,9 @@ def test_bad_pprinter(self):
         with self.assertRaises(AttributeError):
             print('one', PPrintable(), 2, file=self.file, pretty=object())
 
+    def test_fstring(self):
+        self.assertEqual(f'{PPrintable()!p}', "PPrintable('I feel pretty')")
+
 
 if __name__ == "__main__":
     unittest.main()

Lib/test/test_tstring.py

@@ -216,7 +216,7 @@ def test_syntax_errors(self):
             ("t'{x!}'", "t-string: missing conversion character"),
             ("t'{x=!}'", "t-string: missing conversion character"),
             ("t'{x!z}'", "t-string: invalid conversion character 'z': "
-                         "expected 's', 'r', or 'a'"),
+                         "expected 's', 'r', 'a', or 'p'"),
             ("t'{lambda:1}'", "t-string: lambda expressions are not allowed "
                               "without parentheses"),
             ("t'{x:{;}}'", "t-string: expecting a valid expression after '{'"),

Objects/object.c

@@ -862,6 +862,25 @@ PyObject_ASCII(PyObject *v)
     return res;
 }
 
+PyObject *
+PyObject_Pretty(PyObject *v)
+{
+    /* Call `pprint.pformat` */
+    PyObject *printer = PyImport_ImportModuleAttrString("pprint", "pformat");
+    if (!printer) {
+        return NULL;
+    }
+
+    PyObject *prettified = PyObject_CallOneArg(printer, v);
+    Py_DECREF(printer);
+
+    if (!prettified) {
+        return NULL;
+    }
+
+    return prettified;
+}
+
 PyObject *
 PyObject_Bytes(PyObject *v)
 {

Objects/stringlib/unicode_format.h

@@ -760,7 +760,7 @@ MarkupIterator_next(MarkupIterator *self, SubString *literal,
 }
 
 
-/* do the !r or !s conversion on obj */
+/* do the !r, !s, !a, or !p conversion on obj */
 static PyObject *
 do_conversion(PyObject *obj, Py_UCS4 conversion)
 {
@@ -773,6 +773,8 @@ do_conversion(PyObject *obj, Py_UCS4 conversion)
         return PyObject_Str(obj);
     case 'a':
         return PyObject_ASCII(obj);
+    case 'p':
+        return PyObject_Pretty(obj);
     default:
         if (conversion > 32 && conversion < 127) {
                 /* It's the ASCII subrange; casting to char is safe

PC/python3dll.c

@@ -1001,9 +1001,9 @@ _PyPegen_check_fstring_conversion(Parser *p, Token* conv_token, expr_ty conv)
 
     Py_UCS4 first = PyUnicode_READ_CHAR(conv->v.Name.id, 0);
     if (PyUnicode_GET_LENGTH(conv->v.Name.id) > 1 ||
-            !(first == 's' || first == 'r' || first == 'a')) {
+            !(first == 's' || first == 'r' || first == 'a' || first == 'p')) {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(conv,
-                                            "%c-string: invalid conversion character %R: expected 's', 'r', or 'a'",
+                                            "%c-string: invalid conversion character %R: expected 's', 'r', 'a', or 'p'",
                                             TOK_GET_STRING_PREFIX(p->tok),
                                             conv->v.Name.id);
         return NULL;

Parser/action_helpers.c

@@ -5135,7 +5135,7 @@ dummy_func(
 
         inst(CONVERT_VALUE, (value -- result)) {
             conversion_func conv_fn;
-            assert(oparg >= FVC_STR && oparg <= FVC_ASCII);
+            assert(oparg >= FVC_STR && oparg <= FVC_PRETTY);
             conv_fn = _PyEval_ConversionFuncs[oparg];
             PyObject *result_o = conv_fn(PyStackRef_AsPyObjectBorrow(value));
             PyStackRef_CLOSE(value);