How should I build a cpp project with yacc rules?

[Siudya]

Repo: https://github.com/Siudya/cppSaif
Branch: master

I ran xmake and it returned these:

error: In file included from src/saif/Saif.y:39:
In file included from include/SaifUtil.h:32:
In file included from include/SaifDB.h:32:
/usr/include/gmpxx.h:35:10: fatal error: 'iosfwd' file not found
   35 | #include <iosfwd>
      |          ^~~~~~~~
1 error generated.

I try to figure out why so I ran xmake -v and got these:

/usr/bin/bison -d -o build/.gens/saif/linux/x86_64/release/rules/yacc_yacc/Saif.tab.c src/saif/Saif.y
/usr/bin/clang -c -Qunused-arguments -m64 -fvisibility=hidden -O3 -std=c11 -Iinclude -Ibuild/.gens/saif/linux/x86_64/release/rules/yacc_yacc -DNDEBUG -o build/.objs/saif/linux/x86_64/release/gens/rules/yacc_yacc/Saif.tab.c.o build/.gens/saif/linux/x86_64/release/rules/yacc_yacc/Saif.tab.c
In file included from src/saif/Saif.y:39:
In file included from include/SaifUtil.h:32:
In file included from include/SaifDB.h:32:
/usr/include/gmpxx.h:35:10: fatal error: 'iosfwd' file not found
   35 | #include <iosfwd>
      |          ^~~~~~~~
1 error generated.

It seems xmake defaultly bison the yacc file to a C file, while it should be a C++ file. I manually ran

clang++ -c -Qunused-arguments -m64 -fvisibility=hidden -O3 -std=c++20 -Iinclude -Ibuild/.gens/saif/linux/x86_64/release/rules/yacc_yacc -DNDEBUG -o build/.objs/saif/linux/x86_64/release/gens/rules/yacc_yacc/Saif.tab.c.o build/.gens/saif/linux/x86_64/release/rules/yacc_yacc/Saif.tab.c

Forcefully treating c file as cpp file can workaround it.

Is there a technique to address this?

[star-hengxing]

xmake/xmake/rules/lex_yacc/yacc/xmake.lua

Lines 40 to 41 in f446bd8

	local extension = path.extension(sourcefile_yacc)
	local sourcefile_cx = path.join(target:autogendir(), "rules", "yacc_yacc", path.basename(sourcefile_yacc) .. ".tab" .. (extension == ".yy" and ".cpp" or ".c"))

Rename .y -> .yy