document files

Ian Piumarta Ian.Piumarta at
Wed Sep 6 18:12:44 UTC 2000


> perhaps if you make a hello world example I'll get it.

RTFM. ;-)

Oops, the FM isn't in releases prior to 2.8.3 -- scratch that last
piece of advice.  Here are the relevant bits of the FM:

       squeak [ option... ] [ image ] [ script [ argument... ] ]
       The image argument can be followed by a script name.  This
       is the name of a `document' that should contain  Smalltalk
       code  to  be  executed  on  startup.   The document can be
       either the name of a file or a URL starting with  `http:'.

       Any  arguments  that  appear  after  the  script  name are
       ignored, but are made available to the script from  within
       Squeak  via the method getSystemAttribute:.  (See the sec-
       tion SCRIPTS below.)

       If image is given as `--' then squeak bahaves as if  image
       was  not  specified.   This is useful to  specify a script
       without specifying an explicit image.
       Squeak can load and execute  a  `script'  file  containing
       Smalltalk code at startup.  The name of the file should be
       given as the script  argument  to  squeak.   For  example,
       assuming that the image `foo.image' contains an open Tran-
       script window, then the following  represents  the  `hello
       world' program for Squeak:

              Transcript cr; show: 'Hello, world'.

       If  this  script  is  in a file called `hello.sq', then it
       could be run like this:

              squeak foo.image hello.sq

       It is also possible to make `self interpreting' scripts by
       adding  an  `interpreter line' to the start of the script.
       The `hello.sq' file could be changed to

              #!/usr/local/bin/squeak --
              Transcript cr; show: 'Hello, world'.

       and then made executable with

              chmod +x hello.sq

       and then invoked by running the script file directly:

              export SQUEAK_IMAGE

       If any arguments are present after the  script  name  then
       they  can  be  retrieved  from within the script using the

              Smalltalk getSystemAttribute: n

       where n is the index of the argument, starting  at  3  for
       the first argument.  (See the method comment for


       in  the  image  for  an explanation of the meanings of the

       As an example of this, here is the `echo' program  written
       as a Squeak script:

              #!/usr/local/bin/squeak --
              "Echo arguments to the Transcript."
              | i a |
              i := 2.
              [(a := Smalltalk getSystemAttribute: (i := i + 1))
                whileTrue: [Transcript space; show: a].

       When run as

              ./echo.sq one two three

       this would print `one two three' in the Transcript window.

Needless to say, the above will break horribly without the UnixDocFile
changes that I posted an hour ago.

> And I'll also appreciate if you spell out the details of how to make an
> image with the #! in the beginning, is there a handy way to get it into
> the image from inside Squeak?

This isn't as straightforward as it sounds, since there are (or at
least there were) two kinds of images floating around: those that have
a 512-byte remnant (left over from their days as HFS files) before the
real data, and those that potentially don't.  If you've got an image
that doesn't then I don't recommend trying to add an interpreter line
to the front of it.

You could pretty easily write some Squeak to find out if the header is
there or not by looking in the image loading code (which skips over
the header, if it finds one).

For images that have the header, it's pretty easy to add the
interpreter line in Squeak.  After saving the image: open it as an old
binary file, dump

	#!<full-path-to-vm> <any-`-<option>'s-you-like> <Character cr>

in the beginning, then close it.  You can get at <full-path-to-vm>
through one of the system attributes.[1]



[1] Which answers Bert's question from last week regarding whether we
shouldn't stop insisting on absolute paths (and use whatever paths
[including relative] were given on the command line) to the various
files (to avoid problems with broken implementations of realpath(),
like the one in GNU/Linux [heh, heh ;-]).

More information about the Squeak-dev mailing list