The -od (output directory) and -op (perserve source paths) work great when you're compiling multiple modules in a single invocation.  For example, say we have the following:

/foolib/src/foo/bar.d
/myapp/src/main.d

Current Directory: /myapp

```
dmd -I=../foolib/src -I=src -od=obj -op -c src/main.d ../foolib/src/foo/bar.d
```

This example shows a weird unexpected result.  Because I've specified "../foolib/src/foo/bar.d" on the command line, the compiler will put the object file here:

obj/../foolib/src/foo/bar.o

which means it will go here:

/myapp/foolib/src/foo/bar.o

This is very strange.  Because it has a ".." in the name, it doesn't even get put in the "obj" folder specified by "-od".  What makes it worse is if you ad used "-i" instead of giving it on the command line:

```
dmd -I=../foolib/src -I=src -od=obj -op -c src/main.d -i
```

then it would be in:

obj/foo/bar.o

I thought about this for a bit an realized that maybe there's a better way.  Instead of telling the compiler to append the "relative path" of the source file from CWD to the output directory like this:

  `<relative_path>/<basename>.d` -> `<output-dir>/<relative_path>/<basename>.o`
  `../foolib/src/foo/bar.d` -> `obj/../foolib/src/foo/bar.o`

we could tell the compiler to use the path relative of the source file from the package root.  Let's call it the "package path":

  `<some_path>/<package_path>/<basename>.d` -> `<output-dir>/<package_path>/<basename>.o`
  `../foolib/src/foo/bar.d` -> `obj/foo/bar.o`

This would mean modules would go to the same place whether they were explicitly given on the command line or whether they were a "compiled import" via "-i".  It also handles conflicts because each fully-qualified module name (and by extension each "package path" / "module name" combo) must be unique in a compiler invocation.

Note that we would want this to be a new option so as not to break anyone depending on "-op" semantics. Maybe "-om" for "output path based on 'Module' name"?

On Saturday, 1 September 2018 at 14:48:55 UTC, Jonathan Marler wrote:
> Note that we would want this to be a new option so as not to break anyone depending on "-op" semantics. Maybe "-om" for "output path based on 'Module' name"?

LDC has this already as -oq, FWIW.

On Saturday, 1 September 2018 at 23:29:01 UTC, Nicholas Wilson wrote:
> On Saturday, 1 September 2018 at 14:48:55 UTC, Jonathan Marler wrote:
>> Note that we would want this to be a new option so as not to break anyone depending on "-op" semantics. Maybe "-om" for "output path based on 'Module' name"?
>
> LDC has this already as -oq, FWIW.

I knew those LDC folks were smart :) Has there been any attempt to add -oq to dmd?