AutoLoader(3) User Contributed Perl Documentation AutoLoader(3)NAMEPDL::AutoLoader - MatLab style AutoLoader for PDL
SYNOPSIS
use PDL::AutoLoader;
$a = func1(...); # Load file func1.pdl
$b = func2(...); # Load file func2.pdl
$PDL::AutoLoader::Rescan = 1; # Enable re-scanning
DESCRIPTION
This module implements a MatLab style AutoLoader for PDL. If an unknown
function "func()" is called, PDL looks for a file called "func.pdl".
If it finds one, it compiles the file and calls the function "func".
The list of directories to search in is given by the shell environment
variable "PDLLIB". This is a colon-separated list of directories. On
MSWindows systems, is it a semicolon -separated list of directories.
For example, in csh:
setenv PDLLIB "/home/joe/pdllib:/local/pdllib"
Note: This variable is unrelated to Perl's "PERL5LIB".
If you add a leading '+' on a directory name, PDL will search the
entire directory tree below that point. Internally, PDL stores the
dirctory list in the variable @PDLLIB, which can be modified at run
time.
For example, in csh:
setenv PDLLIB "+/home/joe/PDL"
will search /home/joe/PDL and all its subdirectories for .pdl files.
AUTO-SCANNING
The variable $PDL::AutoLoader::Rescan controls whether files are
automatically re-scanned for changes at the "perldl" or "pdl2" command
line.
If "$PDL::AutoLoader::Rescan == 1" and the file is changed then the new
definition is reloaded auto-matically before executing the "perldl" or
"pdl2" command line. Which means in practice you can edit files, save
changes and have "perldl" or "pdl2" see the changes automatically.
The default is '0' - i.e. to have this feature disabled.
As this feature is only pertinent to the PDL 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. :-)
Sample file:
sub foo { # file 'foo.pdl' - define the 'foo' function
my $x=shift;
return sqrt($x**2 + $x**3 + 2);
}
1; # File returns true (i.e. loaded successfully)
AUTHORCopyright(C) 1997 Karl Glazebrook (kgb@aaoepp.aao.gov.au); several
extensions by Craig DeForest (deforest@boulder.swri.edu) All rights
reserved. There is no warranty. You are allowed to redistribute this
software / documentation under certain conditions. For details, see the
file COPYING in the PDL distribution. If this file is separated from
the PDL distribution, the copyright notice should be included in the
file.
BUGS
No doubt this interface could be improved upon some more. :-)
Will probably be quite slow if "$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!
SEE ALSO
For an alternative approach to managing a personal collaction of
modules and functions, see local::lib.
PDL::AutoLoader::expand_path
Expand a compactified path into a dir list
You supply a pathlist and leading '+' and '~' characters get expanded
into full directories. Normally you don't want to use this -- it's
internal to the autoloader -- but some utilities, like the online
documentation searcher, need to be able to use it.
perl v5.18.1 2013-05-12 AutoLoader(3)
