[r6rs-discuss] [Formal] "#! /usr/bin/env" is not "portable." It's Unix-specific. (fwd)

[Arthur A. Gleckler]

On Nov 16, 2006, at 8:38 AM, Per Bothner wrote:

> I think it is useful that it be possible to write a conforming R6RS
> program that is at the same time a valid Unix/Posix script.  That
> requires some minimal standardization in R6RS.  Non-Unix  
> implementations
> need to not get confused by a Unix script header.

It doesn't require standardization in R6RS.  An SRFI is a perfect  
place for this sort of operating system-specific thing.  RnRS has  
always been very careful not to introduce this sort of non-portable,  
operating system-specific behavior.

And why should Unix implementations own the top line of every script  
file?  What happens when another operating system wants control over  
the top line?

> It is also useful to have a standard header so a Scheme file can be
> identified by content, rather than just file extension, which is
> unreliable.  But that requires a standard header for libraries as  
> well,
> though it need not and probably should not be the same header.

Identification of file type by content is no more reliable than by  
extension, and almost certainly less so.