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

[Alan Watson]

Anton van Straaten wrote:
> It may be worth noting that one difference between the case for C and 
> for Scheme is that all the Scheme compilers which currently aim for R5RS 
> compliance (and some that don't) also include "interpreters" that are 
> capable of executing a source file without requiring a separate compile 
> step.  So the degree of applicability of the notion of scripts is far 
> greater across all relevant Schemes, than it is for most C implementations.

Yes, but in my opinion at least, one of the most interesting 
implementations in the last decade or so is stalin, which is most 
certainly not an interpreter. It doesn't aim for R5RS compliance, though.

One can take almost any compiler and convert it into a "script engine" 
by simply compiling the script into a temporary executable, executing 
the executable, and deleting the executable. However, a number of 
current compilers also include interpreters (e.g., Chicken, Guile, and 
Bigloo, last time I looked). For fairly obvious reasons, these 
interpreters often are slower or more limited than the compiler. I think 
most people would consider these interpreters to be more suitable for 
running scripts.

Now, I think in most cases those interpreters are there more to provide 
a REPL than to provide an interpreted script engine. There seems to be a 
trend away from a REPL in the draft R6RS. Therefore, one might also 
expect a trend away from providing interpreters, at least in some 
implementations.

Regardless, my point is not to assert that "no Scheme programs are 
scripts". Some are, and some are not, and forcing all of them to look 
like scripts is unnatural.

Regards,

Alan