Cython cppclass not recognized

[user202729]

---

The name of the parser:

Python, IPythonCell

The command line you used to run ctags:

$ ctags --options=NONE -o - /tmp/a.pyx

The content of input file: (extracted from SageMath source code)

cdef extern from "bliss/graph.hh" namespace "bliss":

    cdef cppclass Stats:
        pass

    cdef cppclass AbstractGraph:
        pass

    cdef cppclass Graph(AbstractGraph):
        Graph(const unsigned int)

The tags output you are not satisfied with:

Graph   /tmp/a.pyx      /^    cdef cppclass Graph(AbstractGraph):$/;"   f

The tags output you expect:

AbstractGraph   /tmp/a.pyx      /^    cdef cppclass AbstractGraph:$/;"        c
Graph   /tmp/a.pyx      /^    cdef cppclass Graph(AbstractGraph):$/;"   c
Stats   /tmp/a.pyx      /^    cdef cppclass Stats:$/;"        c

The version of ctags:

$ ctags --version
Universal Ctags 6.1.0(v6.1.0), Copyright (C) 2015-2023 Universal Ctags Team
Universal Ctags is derived from Exuberant Ctags.
Exuberant Ctags 5.8, Copyright (C) 1996-2009 Darren Hiebert
  Compiled: Mar 17 2024, 12:18:39
  URL: https://ctags.io/
  Output version: 0.0
  Optional compiled features: +wildcards, +regex, +iconv, +option-directory, +xpath, +json, +interactive, +sandbox, +yaml, +packcc, +optscript, +pcre2

How do you get ctags binary:

Arch Linux package

[masatake]

Thank you. Cython is yet another parser I would like to rewrite. Here is a quick solution.

diff --git a/parsers/python.c b/parsers/python.c
index 0403fcc43..f23ccdbdd 100644
--- a/parsers/python.c
+++ b/parsers/python.c
@@ -156,6 +156,7 @@ static const keywordTable PythonKeywordTable[] = {
 	{ "cimport",		KEYWORD_import			},
 	{ "class",			KEYWORD_class			},
 	{ "cpdef",			KEYWORD_cpdef			},
+	{ "cppclass",		KEYWORD_class			},
 	{ "def",			KEYWORD_def				},
 	{ "extern",			KEYWORD_extern			},
 	{ "from",			KEYWORD_from			},

[masatake]

I will make a pull request after solving the CI/CD related issues.

[masatake]

I read https://github.com/mkoeppe/bliss/blob/sage_package/graph.hh.

It is challenging (and interesting) to make a model for a language to glue languages together.

    cdef cppclass Stats:
        pass

The primary task of ctags is extracting the name defining something. e.g.

ctags extracts foo from the following Python script:

def foo(n):
    pass

However, ctags doesn't extract bar as a definition tag from the following Python script:

import bar;

because this code doesn't define bar. This code refers bar defined somewhere. Instead, ctags extracts bar as a reference tag.

    cdef cppclass Stats:
        pass

I wonder whether this code defines Stats. From a point of view, this code refers to a C++ class defined somewhere and declared in bliss/graph.hh. ctags can make a reference tag in this case.

From a point of view, this code defines a new Python class. Making two tag entries for Stats looks better.

I discussed a similar topic ago when enhancing Basic parser. https://github.com/universal-ctags/ctags/pull/3284

The modeling for solving this issue must be consistent with the discussion.