The program
const mydir = embeddir("mydir");
Console.WriteLine(FS.ReadAllText(mydir,"/cross.json")); //prints the file contents of the embedded file from res/mydir/cross.json

The res dir files

res/mydir/cross.json
res/mydir/src/main.tcross
res/mydir/src/other.tcross
res/mydir/res/icon.png

the dictionary generated by the compiler

{
    .["cross.json"] = () => embedstrm("mydir/cross.json"),
    .["src"] = {
        .["main.tcross"] = () => embedstrm("mydir/src/main.tcross"),
        .["other.tcross"] = () => embedstrm("mydir/src/other.tcross")
    },
    .["res"] = {
        .["icon.png"] = ()=> embedstrm("mydir/res/icon.png")
    }
}

the instruction embeddir is right after the dictionary generated by compiler
this instruction pops the dictionary and returns a wrapper filesystem called EmbedDirectory