Re: Alternative to hash-bang

[Alan Barrett <apb%cequrux.com@localhost>]

On Fri, 18 Jul 2014, D'Arcy J.M. Cain wrote:
> Greg Troxel <gdt%ir.bbn.com@localhost> wrote:
> > Once --!! happens, then there will be requests to add all sorts of
> > things, and this seems like a mess.  Surely it's easy enough to teach
>
> As I said, '#', ';' and '--' seem to cover most situations.  Maybe '%'
> to a much smaller extent.  Can you think of many other possibilities?

Are you proposing to make the kernel recognise several new
#!-equivalents?

It would be easy, and flexible, and not especially ugly, to make 
the kernel scan for "#!" at some non-zero offset in the file.  Say 
at all offsets from 0 to 4, inclusive.  Then you could write up 
to 4 bytes to make the other interpreter think it's a comment, 
followed by the traditional #! stuff.  If you need %%-- to make 
the other interpreter think the line is a comment, then write 
%%--#!/usr/local/bin/interpreter.

--apb (Alan Barrett)