Re: guile bangline

[Michael Vanier <mvanier at bbb dot caltech dot edu>]

[James Dean Palmer]
> 
> 
> I noticed that python scripts use a bangline with /usr/bin/env to
> envoke python - this makes it extremely portable to systems where
> python is not installed in the same place.
> 
> I am using three different systems with guile installed in three
> different places - which is rather cumbersome.   I was wondering if
> there was a way to use env in conjunction with the guile #! ... !#
> notation?  And if this could be done, wouldn't it be a good general
> policy for script writers? 

I and other people have brought this up from time to time.  So far there
hasn't been a good solution proposed, but the problem isn't with the #!
... !# notation (which is potentially quite useful).  The problem seems to
be that:

1) /usr/bin/env can only reliably (e.g. portably) execute one argument in a
   #! line.  I believe this is a limitation of the #! mechanism, not of env.

2) Running guile on a script requires invoking "guile -s", not just
   "guile".

Experts, please correct me if I'm wrong on either of the above two issues.
I've got a quick hack fix: a shell script I call "guiles":

  #! /bin/sh
  /usr/bin/env guile -s ${1+"$@"}; exit $?

Then you can do this in your guile programs:

  #! /usr/bin/env guiles
  !#

  ;; your code here...

This works for me; YMMV.  I wish there was a standard way to do this,
though.  I don't know why the "-s" option couldn't be the default, for
instance.  IMO the current setup puts guile at a significant disadvantage
with respect to other scripting languages, which (again IMO) is more
important than maintaining strict scsh/scm compatibility if we really want
guile to take over the world :-)

Mike


--------------------------------------------------------------
Mike Vanier	mvanier@bbb.caltech.edu
Department of Computation and Neural Systems, Caltech 216-76
GNU/Linux: We can't lose; we're on a mission from God.