nim.cfg but for Nelua?

[stefanos82]

With Nim we can use custom settings with the help of nim.cfg in a project's directory.

I would like to use ccache gcc at a global usage; I know it works with nelua --cc="ccache gcc" which helps reducing the compilation time exponentially, so I would like it to be my default setting.

Does Nelua support custom config settings somehow?

[edubart]

Yes, sorry as this is not in the documentation yet, but this is supported, you can create neluacfg.lua files in the following directories:

• $HOME/.config/nelua/neluacfg.lua for global configurations across the system
• .neluacfg.lua in the current directory nelua is running from for per project configuration

The compiler will give priority for command line flags, then .neluacfg.lua in the current directory and finally fallback to $HOME/.config/nelua/neluacfg.lua for global configuration in the system.

The following is an example of its contents:

return {
  cc="ccache gcc",
  cflags="-Wall -Wextra",
  add_path={
    '/home/bart/projects/nelua/nelua-decl/libs/?/?.nelua',
  }
}

The file can have most options from nelua --help, but you need to use the full option name and replace any - with _.

[stefanos82]

An interesting behavior takes place. With

return {
  cc="ccache gcc",
  cflags="-Wall -Wextra",
}

it generates the following code: /* Compile command: ccache gcc "nelua_cache/auto.c" -o "nelua_cache/auto" -Wall -fwrapv -g -Wall -Wextra -lm */

[edubart]

This is expected, the compile command is always saved as a comment in the source file, thus the generated C file will have a different hash when changing the cflags or C compiler, thus Nelua won't use any cached compilation whenchanging the cflags or C compile. Nelua compiler need to save the compile command somewhere for this, and it's saved in the source, also saving there hints any user reading the C source what compiler and flags where used to compile the source in question.

[stefanos82]

That's not what I meant. -Wall is found twice and the weird thing to me is that it places my own flags right before the end of -Wall -fwrapv -g -lm, between -g and -lm to be more precise.

[edubart]

Oh, it's because -Wall is enabled by default at the moment and adding it in the neluacfg.lua was not really needed, just added as an example, so you can remove it.

[stefanos82]

Ah OK. I've just tested it; works as expected 🥳