Fix #75: Support __attribute__ within struct declarations

[retif]

This commit fixes issue #75 where attribute specifiers within struct declarations were not parsed correctly, leading to a ParseError.

Example code that now parses correctly:

    typedef struct {
        __attribute__((__deprecated__)) int test1;
    } test2;

Changes:

• Extended specifier_qualifier_list rule in GnuCParser to handle function_specifier nodes, allowing attribute within structs
• Added _p_specifier_qualifier_list_left_recursion method to correctly handle AttributeSpecifier nodes in the funcspec list
• Modified _generate_decl in GnuCGenerator to handle funcspec list with AttributeSpecifier nodes
• Improved AttributeSpecifier.eq to use structural comparison of AST nodes instead of object identity
• Added round-trip test to verify the fix

[inducer]

Thanks!

[inducer]

@retif Want to be co-maintainer? (Sent you an invite)

[retif]

@retif Want to be co-maintainer? (Sent you an invite)

Sure, thanks, accepted the invite

[simonlindholm]

DeclExt seems to be unused?

Edit: also confused about why AttributeSpecifier should have a __eq__ when all other AST nodes are compared by object identity.

[retif]

@simonlindholm thank you, removed the unused function.

Answering your question, its because:

from pycparserext.ext_c_parser import GnuCParser

parser = GnuCParser()
src = '__attribute__((unused)) int foo;'

decl_1 = parser.parse(src).ext[0]
decl_2 = parser.parse(src).ext[0]

print(decl_1.funcspec)             # [AttributeSpecifier(...)]
print(decl_1.funcspec[0] == decl_2.funcspec[0])  # False without the custom __eq__