[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Several comments

This page is part of the web mail archives of SRFI 22 from before July 7th, 2015. The new archives for SRFI 22 contain all messages, not just those from before July 7th, 2015.

> Marc> and "scheme-script" would always invoke "script-main" after loading a
> Marc> script.
> I can imagine going with that.  Opinions, anyone else?

Can you explain your position on the other alternatives.  In
particular the second one which is my preference:

  #! /bin/sh
  "exec" "scheme-script" "$0" "$@"
  (define (main arg1 arg2)
    (write (+ (string->number arg1) (string->number arg2))))
  (apply main (script-arguments))

I forgot to mention that it allows scripts to be compiled to an
executable program (i.e. a.out), as well as to a "fasl" file.  For
this to work, "script-arguments" behaves as follows depending on the

1) In the dynamic extent of a "load": (script-arguments) signals the
   error "Attempt to load a script in an inappropriate context".  This
   happens whether the file loaded is a source code file or a "fasl"

2) In all other contexts, and in particular during loading as a script
   by scheme-script and during the execution of a compiled program:
   (script-arguments) returns the command line arguments as a list of

For example, the above script could be compiled with Gambit to an
"a.out" simply with:

   % gsc S.scm
   % gcc S.c S_.c -lgambc
   % a.out 100 200

There is no need for the compiler to know that it is compiling a

My third alternative, based on the implicit call of a "script-main"
procedure, requires the compiler to know it is compiling a script so
it has to be given a special compilation option, or detect that the
file being compiled starts with "#!" (actually it is a bit more
complicated because it is the linker that has to know it is generating
an executable and one of the source files was a script).