ARM assembly syntax file using .s file extension conflicts with asm.yaml

[phpeterson-usf]

Description of the problem or steps to reproduce

I would like to use micro for a project in ARM assembly language, and could contribute a syntax file for that instruction set. However, our source files use the extension .s, which is already used by the built-in syntax file for x86 assembly language. I looked at the detect/header syntax in YAML, but the Go code in ftdetect.go prefers the file extension to the firstLine header. I can see two cumbersome ways to make this work:

1. Make up a bogus file extension like .as for ARM assembly language
2. Type set filetype armasm every time I open a file this doesn't work

Is there a better way? If not, can we make something up, like maybe allowing the firstLine header to take priority over the file extension?

Specifications

Version: 2.0.2
Commit hash: c51f849
Compiled on February 26, 2020

[sparques]

If you take a look at the ftoptions plugin, you can use that as a template to write your own plugin that detects your filetype and changes the filetype option.

I think something like, if ft == "asm" then if {custom detect code} {filetype = armasm}

[sparques]

Okay, I went ahead and wrote this for you.

function onBufferOpen(b)
    local ft = b:FileType()

    if ft == "asm" then
    	if string.find(b:Line(0), "armasm") then
    		b:SetOption("filetype","armasm")
    	end
    end
end

Not sure what your arm asm file looks like. If you add a comment to to the top of your file, containing the string "armasm" this will detect it. Or you can figure out something else.

You need a separate syntax file defining armasm syntax, of course.

To use this, mkdir -p ~/.config/micro/plug/armhelper
Store the function in ~/.config/micro/plug/armhelper/armhelp.lua

[phpeterson-usf]

Thanks. I thought I would make it more readable by making the filetype arm-asm, and naming the plugin to match. However, my plugin never got called. It appears that this line of code does not permit dashes in the filenames of runtime files :-)

Now the filetype switch (to arm_asm) works, but that seems to break syntax highlighting. I will file a separate issue on that.

[phpeterson-usf]

I would really like to see something like this in a comment in the source file:
/* micro:set filetype arm_asm */
as vim does
Want to repurpose this issue? Or close and open a new one?

FWIW, I wonder if micro already has contention for file extensions with C++. runtime/syntax/ contains two syntax files for C++ (cpp.yaml and c++.yaml), both claiming .cpp files. Is there a way to apply one or the other? Or first one encountered wins?

[zyedidia]

By the way, it should be possible to achieve a similar effect to the plugin by adding the following to your settings.json:

{
...
    "*.s": {
        "filetype": "arm_asm"
    }
...
}

[phpeterson-usf]

Does that approach lock users into a one-to-one relationship between file extensions and syntax files? I'm looking for an approach which allows file extensions to have a one-to-many relationship with syntax files. That's certainly the real-world scenario for .s files files representing completely different architectures.

I also imagine one-to-many would be useful for other languages as they evolve, gaining new syntax or deprecating old syntax. For example, one-to-many would allow Micro to edit python3 files with a .py extension, which might be nice too.