PDL::AutoLoader - MatLab style AutoLoader for PDL
use PDL::AutoLoader; $a = func1(...); # Load file func1.pdl $b = func2(...); # Load file func2.pdl
$PDL::AutoLoader::Rescan = 1; # Enable re-scanning
This module implements a MatLab style AutoLoader for PDL. If a unknown function 'func()' is called then a file 'func.pdl' is searched for and if found is read in to define 'func()' which is then executed.
Files are seached for using the directories in seach path @PDLLIB, which
is initialised from the shell environment variable PDLLIB which is a
colon seperated list of directories.
e.g. in csh
setenv PDLLIB "/home/kgb/pdllib:/local/pdllib"
Note this is kept seperate from PERL5LIB just in case.
As an added bonus, you can use a leading '+' on a directory name to search not just that directory but the entire directory tree under it (excluding symlinks). The subdirs are determined by explicit search, and searches occur at startup and again each time you change the number of elements in @PDLLIB.
For example, setenv PDLLIB ``+~kgb/PDL''
will search /home/kgb/PDL and all its subdirectories for .pdl files.
The variable $PDL::AutoLoader::Rescan controls whether files
are automatically re-scanned for changes at the perldl command
line.
If $PDL::AutoLoader::Rescan == 1 and the file is changed
then the new definition is reloaded auto-matically before
executing the perldl command line. Which means in practice
you can edit files, save changes and have perldl see the
changes automatically.
The default is '0' - i.e. to have this feature disabled.
As this feature is only pertinent to the perldl shell it imposes
no overhead on PDL scripts. Yes Bob you can have your cake and
eat it too!
Note: files are only re-evaled if they are determined to have been changed according to their date/time stamp.
No doubt this interface could be improved upon some more. :-)
sub foo { # file 'foo.pdl' - define the 'foo' function
my $x=shift;
return sqrt($x**2 + $x**3 + 2);
}
1; # File returns true (i.e. loaded successfully)
Copyright(C) 1997 Karl Glazebrook (kgb@aaoepp.aao.gov.au)
All rights reserved. There is no warranty. You are allowed
to redistribute this software / documentation under certain
conditions. For details, see the file COPYING in the PDL
distribution. If this file is separated from the PDL distribution,
the copyright notice should be included in the file.
No doubt this interface could be improved upon some more. :-)
Will probably be quite slow if $PDL::AutoLoader::Rescan == 1
and thousands of functions have been autoloaded.
There could be a race condition in which the file changes while the internal autoloader code is being executed but it should be harmless.
Probably has not been tested enough!