Documention for: bin-save.r
Created by: btiffin
 on: 25-Apr-2007
Last updated by: btiffin on: 25-Apr-2007
Format: text/editable
Downloaded on: 18-Apr-2024

Using %bin-save.r

  Source code originally by Unknown
  Usage document written by Brian Tiffin, Library Team apprentice
  24-Apr-2007

===Introduction to %bin-save.r

Another script that is more for reading and learning than running.

This example highlights REBOL's power of datatyping.  In this case
the binary! data type, or more specifically a <b>MOLD</b>ed binary!,

Unlike other programming enironments, you can "see" a
binary! as a editable string, once molded, and REBOL can load
and save data in this form.

REBOL lets you include data, right in the source, that would
be near impossible to use an editor with in other environments.

This script needs to be scanned, and then executed for full
appreciation.

===Using %bin-save.r

Another simple one, Just <b>DO</b> it.  Well, not quite, there is 
a little setup for this one.

Place the script in a directory that you permissions to write files
to, and includes an image file, named <b>%rebol-banner.gif</b>
If you don't have %rebol-banner.gif, run the sister script to
this one, <b>%bin-data.r</b> to create %banner.gif and then

  >>rename %banner.gif %rebol-banner.gif

Start up REBOL with the <b>-s</b> option, or answer Yes or All to the
security dialog.

From a console session,

  >>do %bin-save.r

or

  >>do http://www.rebol.org/cgi-bin/cgiwrap/rebol/download-a-script.r?script-name=bin-save.r

and REBOL will save a molded string from the image file, <b>%rebol-banner.gif</b>
to disk as readable REBOL code, in <b>%banner.r</b>.  This file can then be
cut and pasted into a script, or left as a simple datafile.

===Filenames in REBOL

Note:  REBOL uses % (percent) before a filename, as this is a
builtin datatype.  The REBOL scanner uses the %rebol-banner.gif syntax
to "know", deep down "know", that you mean the <b>file</b> rebol-banner.gif.

This may seem a little strange at first, but you'll be slinging
filenames around using the percent syntax, before you know it.

===system/options/binary-base

The REBOL system object an internal control variable that controls the
numeric base for binary! molding and conversion.

<b>%bin-save.r</b> holds the %banner.r file as a base 64 
molded binary! or %rebol-banner.gif. By default, REBOL uses a
<b>system/options/binary-base</b> value of 16.  The binary! would
then mold to a hexadecimal string.

Base 64, packs more binary! into the string version as it can use more
symbols to represent values.

Common values for  <b>system/options/binary-base</b> are
64, <b>16</b>, and 2.  The default of 16 is usually fine, unless you
really want to shrink down included string forms of binary data.

The sister script to this one, <b>%bin-data.r</b> shows an example
of a binary-base 64 molded binary string.