Hi!

On Tue, Jun 19, 2012 at 7:53 AM, Heinrich Apfelmus <apfelmus@quantentunnel.de> wrote:

In addition, I don't know how to implement this function correctly.
For example, if you alias ghc to another name the heuristic in the
executable-path package fails:

Good point. For the use case mentioned above, any quick and dirty heuristic that works most of the time would be sufficient, though.

Ideally, Haskell interpreters would set an environment variable when they interpret a source file.

Since

* we can't implement this reliably,
* the distinction into these three groups doesn't necessarily work for all compilers, and

* the distinction (I assume) isn't useful in most use cases

Another problem with the executable-path like distinction is that it's no longer possible to find out which executable (i.e. ghc) is running the script. At a minimum the Script and Interactive constructors would have to expose that.

getExecutablePath :: IO FilePath

has a clear meaning: return the path to the executable that's currently executing. If we want a function that provides the script/interactive/executable guessing, we should provide both functions. The guessing one should have this warning:

-- N.B. This function might return Executable in the case of Script/Interactive and vice versa.

-- Johan