generate C code before build

[Freed-Wu]

There are some tools to generate C code such as:

• cython: convert python to C
• lua-native-object: convert lua to C

-- luacheck: ignore 113
---@diagnostic disable: undefined-global
add_rules("mode.debug", "mode.release")

rule("lua-native-object")
do
    set_extensions(".nobj.lua")
    before_build_file(function(target, sourcefile)
        import("core.project.config")
        os.run("native_objects.lua -outpath %s -gen lua %s", get_config("buildir"), sourcefile)
        target:add("files", get_config("buildir") .. "/" .. path.basename(sourcefile) .. ".c")
    end)
end

target("tellenc")
do
    add_rules("luarocks.module", "lua-native-object")
    add_files("*.cpp", "*.nobj.lua")
    add_links("stdc++")
end

However,

error: /nix/store/va7kw1i822h95im4jacci19v0cqajfyf-binutils-2.43.1/bin/ld: cannot find build/.objs/tellenc/linux/x86_64/release/build/module.nobj.c.o: No such file or directory

It looks like when we convert lua to C code then add it to sources, it will miss compiling, so *.c.o is not found.

[waruqi]

see https://github.com/xmake-io/xmake/blob/dev/xmake/rules/lex_yacc/lex/xmake.lua

[Freed-Wu]

I found a empty.c is needed for link. e.g.

    add_files("*.nobj.lua")

/nix/store/3ix5h74n7ar9950vwzp4dxmil70pmx0k-gcc-wrapper-13.3.0/bin/gcc -o build/linux/x86_64/release/rime.so build/.objs/rime/linux/x86_64/release/gens/rules/lua-native-object/rime.nobj.c.o -shared -m64 -fPIC

After add a empty.c:

    add_files("*.nobj.lua", "*.c")

/nix/store/3ix5h74n7ar9950vwzp4dxmil70pmx0k-gcc-wrapper-13.3.0/bin/gcc -o build/linux/x86_64/release/rime.so build/.objs/rime/linux/x86_64/release/rime.c.o build/.objs/rime/linux/x86_64/release/gens/rules/lua-native-object/rime.nobj.c.o -shared -m64 -fPIC -L/nix/store/r4d1aphfpvpfj9g2lw6qsnxz42adfc61-librime-1.12.0/lib -s -lrime

How to force link?

[waruqi]

add_rules("c")