History for Using Cmiss Perl

changed:
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<ul><li>
<b>Output.</b> If you want all your commands echoed when they actually happen then
you can get the interpreter (itp environment) to do this for you.
<br>'itp set echo on'
<br>By default the echoed commands are written verbatim.  You can choose to
		  add a string to the start of every echoed line using.....
<br>'itp set echo prompt :)'
</li><li>
<b>Debug.</b> If you really want to see the lexical analysis of the Perl
interpreter then you can get the interpreter to write this out.
<br>'itp set debug on'
</li><li>
<b>Comfiles.</b>If you are reading a comfile containing a mixture of Perl and Cmiss
commands then you must continue to read it in with read com;FILENAME or 
open comfile FILENAME exec so that the cmiss commands get mangled into
Perl.  If your script is pure perl then you can use require, do or use as
normal.
</li><li>
Each space separated expression is assumed to be a single token for
cmiss.
<br>i.e. gfx cre win "bob is a fish" creates a window called "bob is a
fish"
this means that
<br>	$fred = "win bob"
<br>	gfx cre $fred 
<br>does not create a window called bob.  To do something like this see the
next section.
</li><li><b>The cmiss command.</b> The Perl interpreter works by declaring a function Perl_cmiss::cmiss
or just cmiss, that is a valid Perl function.  If for some reason the
Perl interpreter won't interpret your cmiss command the way you think it
should then you can pass this function a string and that string will go
directly to cmiss.
<br>i.e.  $bob = "win 10"; cmiss("gfx cre $bob");
</li><li><b>The gfx * separator.</b> As an asterisk now denotes multiplication the
		  use of asterisks to separate directions in element and glyph sizes
		  must now be quoted.
<br>gfx mod g_e heart element_points size 2*1*0.4 is actually the same as
		  gfx mod g_e heart element_points size 0.8
<br>so instead quote the terms, gfx mod g_e heart element_points size "2*1*0.4"
</li><li><b>Comments.</b> The comment character is now a #.
</li><li><b>open.</b> As open is a valid function in Perl and a starting keyword in
		  CMISS you currently need to escape the CMISS to use the Perl one.  You
		  could enclose it in ()'s or explicitly use its module name CORE::open.
</li><li><b>Listing variables.</b> You can list all your defined variables by
		  looking at the hash of your package.  The hash is called cmiss::.
<br>print map { "$_\n" } keys %cmiss::;
<br>A more user friendly command for this may be put directly into cmiss.
		  There are some routines for simplifying this in the module
		  CMISS::Utils found in CMISS_ROOT/perl_lib, in particular pscalar,
		  parray and phash.
</li><li><b>ENV environment.</b> If you want to reference something in your
		  environment then you can just use the automatic Perl Hash ENV.  So to
		  reference the environment variable HOST use $ENV{HOST}.
<br>i.e.  print "Host from ENV is $ENV{HOST}\n";
</li><li><b>itp assert blocks closed.</b> The interpreter suspends execution of
		  commands until all control structures are complete, i.e. until the
		  closing bracket of all if, for and while statements is reached.
		  Sometimes you may be trapped inside some control loop, nothing will
		  execute and you are unsure how deep you are.  You can either keep
		  typing } brackets to try and escape any control statements you are in
		  or you can use the interpreter command, 'itp assert blocks closed'.
		  This command will generate an error if you are in any level of control
		  structure at that time, it will also reset the interpreter,
		  immediately terminating any control structures that may be started
		  without executing them.
</li><li><b>Command line arguments.</b> Cmiss commands can be passed directly to the
		  interpreter through command line arguments.  These are executed first,
		  before any startup comfiles or command line comfiles.  This is useful
		  for simple operations such as defining variables used by a comfile.
		  Valid Perl can be separated by semicolons to form multiple statements.
<br>i.e. cm -exec '$FRED="fredstring"; $BOB="bobstring"'
</li></ul>