gh-122943: Add the varpos parameter in _PyArg_UnpackKeywords

[serhiy-storchaka]

Remove _PyArg_UnpackKeywordsWithVararg.
Add comments for integer arguments of _PyArg_UnpackKeywords.

This is a follow up of #122945. It was not included in #122945 to minimize the diff.

• Issue: Re-work support of var-positional parameters in Argument Clinic #122943

[erlend-aasland]

Neat. Consider this style amendment for IMO slightly more readable generated code:

diff

diff --git a/Tools/clinic/libclinic/parse_args.py b/Tools/clinic/libclinic/parse_args.py
index 8b7afbcf3e4..8d1714b1ebe 100644
--- a/Tools/clinic/libclinic/parse_args.py
+++ b/Tools/clinic/libclinic/parse_args.py
@@ -695,13 +695,21 @@ def parse_general(self, clang: CLanguage) -> None:
                 if has_optional_kw:
                     self.declarations += "\nPy_ssize_t noptargs = %s + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - %d;" % (nargs, self.min_pos + self.min_kw_only)
                 unpack_args = '_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL'
-            parser_code = [libclinic.normalize_snippet(f"""
-                {argsname} = _PyArg_UnpackKeywords({unpack_args}, &_parser,
-                        /*minpos*/ {self.min_pos}, /*maxpos*/ {self.max_pos}, /*minkw*/ {self.min_kw_only}, /*varpos*/ {1 if self.varpos else 0}, argsbuf);
+            snippet = f"""
+                {argsname} = _PyArg_UnpackKeywords(
+                    {unpack_args}, &_parser,
+                    /*minpos*/ {self.min_pos},
+                    /*maxpos*/ {self.max_pos},
+                    /*minkw*/ {self.min_kw_only},
+                    /*varpos*/ {1 if self.varpos else 0},
+                    argsbuf
+                );
                 if (!{argsname}) {{{{
                     goto exit;
                 }}}}
-                """, indent=4)]
+            """
+            snippet = libclinic.normalize_snippet(snippet, indent=4)
+            parser_code = [snippet]
 
         if self.requires_defining_class:
             self.flags = 'METH_METHOD|' + self.flags

[skirpichev]

Consider this style amendment for IMO slightly more readable generated code:

(This is why auto-formatting for clinic output (with indent-like tool) might be not a bad idea.)

But if we are going for multi-line code snippet, lets add also spaces to comments: /*minpos*/ -> /* minpos */.

[erlend-aasland]

(This is why auto-formatting for clinic output (with indent-like tool) might be not a bad idea.)

We already do auto-formatting of clinic output¹; see Tools/clinic/libclinic/formatting.py. But I don't think coercing Argument Clinic to produce "100% correct PEP-7 code" is good use of anyones time. Time is better spent on resolving real Argument Clinic issues.

Footnotes

1. its just that some parts of the generator is not producing very readable code (yet) ↩

[serhiy-storchaka]

Consider this style amendment for IMO slightly more readable generated code:

It would be less readable to me. I have vision problems so I get lost in very scattered code.

But if we are going for multi-line code snippet, lets add also spaces to comments: /*minpos*/ -> /* minpos */.

I initially wrote it as /* min_pos */, but it was too noisy. It was more difficult to find the code between comments.