I have some Perl code that uses require instead of use to load a specific module, and I have just discovered that my code requires a minimum version on that module. However, unlike use, require does not seem to have a version argument when loading a module. So what is the proper way to do this?
You can call for VERSION method, it's inherited from the UNIVERSAL class. It checks for $Module::VERSION variable:
require Any::Module;
Any::Module->VERSION('2.3');
Related
I have a class module and I'm forced to use PowerShell 4. It doesn't recognize the "using" keyword as it was introduced in PS5.
Is there a way around this?
Is there a way around this?
No!
Classes (and the using ... directives) were introduced in Windows PowerShell 5.0 - the parser in previous versions wouldn't know what to do with either keyword.
If you want to retain backwards compatibility with 4.0 you need to remove all type definitions and using statements from the module code and leverage either pre-compiled binaries or define your custom types with Add-Type at runtime instead.
I am using this software called Simple Agent Pro, and it primarily uses TCL code. I was wondering anybody familiar with TCL or Sapro would be kind enough to tell me how to import the modules into the .tel file for Sapro.
When I try this:
package require tclOO.h
The program stops working.
Any help would be appreciated.
I don't know Simple Agent Pro at all, but if you're doing a “guerilla install” of TclOO then you need a few things:
Make sure you're using Tcl 8.5 (see what package require Tcl returns).
If you're using 8.4 (note: 8.4 EOLed this month), TclOO will not work at all (and it cannot be backported).
If you're using 8.6, it already provides the TclOO package and you shouldn't need to fuss around with all this.
Do a build of TclOO and install it to a location you prefer.
This will require Tcl's internal source files; TclOO explicitly pokes its nose into places where most code shouldn't.
You probably don't need to have a custom build of 8.5; just the configured sources somewhere will do. (You might need to hack the configure scripts a little bit.)
Add the location that you installed TclOO to to the search path inside your Tcl 8.5 program.
lappend auto_path /the_dir/you_put/it_in
If you're using Windows, it's probably easiest to use forward slashes for this path anyway (this is a directory name that is always highly protected before it hits the OS, so that's OK).
Now you should be able to require/use the package.
package require TclOO
oo::class create Foo {
# etc.
}
Note that the case and exactly how you write it matters. The version you get ought to be at least 1.0 (earlier versions were for development only) which corresponds exactly with the API as supported in Tcl 8.6 (modulo a few things that require 8.6 for other reasons, such as being able to yield inside a method which only works in 8.6 because that's where yield was first defined).
You probably mean
package require TclOO
Case and other stuff is important there.
Next time you should also include the stack trace. If the program stops working, it should display that either as dialog or on stdout.
I have a lot perl code that does different things in test and production, and I want to lock my code to specific versions of CPAN modules in case there are some changes to some of them in the future which may possibly break my code.
So I want to use specific versions of all the modules I use. By use I mean
use XML::Smart
To use specific module refer only
use only MyModule => 0.30;
Also to print error if module version you want is above to currently installed one
You can say
use XML::Smart v1.6.9;
or
use XML::Smart 1.6.9;
or
for backward compatibility
use XML::Smart 1.006_009;
With reference from perldoc :
use Module VERSION LIST
use Module VERSION
use Module LIST
use Module
use VERSION
If the VERSION argument is present between Module and LIST, then the
use will call the VERSION method in class Module with the given
version as an argument. The default VERSION method, inherited from the
UNIVERSAL class, croaks if the given version is larger than the value
of the variable $Module::VERSION .
You can do the low tech thing:
BEGIN {
use XML::Simple;
die "..." unless XML::Simple->VERSION eq '1.23';
}
There is a headache knowing how a particular module reports its version. The version module is supposed to do version math, but I haven't found it reliable since there are too many ways to specify a version.
How can I perform a "shallow" syntax check on perl files. The standard perl -c is useful but it checks the syntax of imports. This is sometimes nice but not great when you work in a code repository and push to a running environment and you have a function defined in the repository but not yet pushed to the running environment. It fails checking a function because the imports reference system paths (ie. use Custom::Project::Lib qw(foo bar baz)).
It can't practically be done, because imports have the ability to influence the parsing of the code that follows. For example use strict makes it so that barewords aren't parsed as strings (and changes the rules for how variable names can be used), use constant causes constant subs to be defined, and use Try::Tiny changes the parse of expressions involving try, catch, or finally (by giving them & prototypes). More generally, any module that exports anything into the caller's namespace can influence parsing because the perl parser resolves ambiguity in different ways when a name refers to an existing subroutine than when it doesn't.
There are two problems with this:
How to not fail -c if the required modules are missing?
There are two solutions:
A. Add a fake/stub module in production
B. In all your modules, use a special catch-all #INC subroutine entry (using subs in #INC is explained here). This obviously has a problem of having the module NOT fail in real production runtime if the libraries are missing - DoublePlusNotGood in my book.
Even if you could somehow skip failing on missing modules, you would STILL fail on any use of the identifiers imported from the missing module or used explicitly from that module's namespace.
The only realistic solution to this is to go back to #1a and use a fake stub module, but this time one that has a declared and (as needed) exported identifier for every public interface. E.g. do-nothing subs or dummy variables.
However, even that will fail for some advanced modules that dynamically determine what to create in their own namespace and what to export in runtime (and the caller code could dynamically determine which subs to call - heck, sometimes which modules to import).
But this approach would work just fine for normal "Java/C-like" OO or procedural code that only calls statically named predefined public subs, methods and accesses exported variables.
I would suggest that it's better to include your code repository in your syntax check. perl -I/path/to/working/code/repo/local_perl/ -c or set PERL5LIB=/path/to/working/code/repo/local_perl/ prior to running perl -c. Either option should allow you to check against your working code, assuming you have it in a directory structure similar to your live code.
I guess you could make stubs for the missing libraries in your home folder.
Have you looked into PPI? I think it does follow imports, however it could perhaps be more easily modified to guess what looks like a function name.
I'm getting ready to try to deploy some code to multiple machines. As far as I know, using a Makefile.pm to track dependencies is the best way to ensure they are installed everywhere. The problem I have is I'm not sure our Makefile.pm has been updated as this application has passed through a few different developers.
Is there any way to automatically parse through either my source or a few full runs of my program to determine exactly what versions of what modules my application is depending on? On top of that, is there any way to filter it based on CPAN packages? (So that I only depend on Moose instead of every single module that comes with Moose.)
A third related question is, if you depend on a version of a module that is not the latest, what is the best way to have someone else install it? Should I start including entire localized Perl installations with my application?
Just to be clear - you can not generically get a list of modules that the app depends on by code analysis alone. E.g. if your apps does eval { require $module; $module->import() }, where $module is passed via command line, then this can ONLY be detected by actually running the specific command line version with ALL the module values.
If you do wish to do this, you can figure out every module used by a combination of runs via:
Devel::Cover. Coverage reports would list 100% of modules used. But you don't get version #s.
Print %INC at every single possible exit point in the code as slu's answer said. This should probably be done in END{} block as well as __DIE__ handler to cover all possible exit points, and even then may be not fully 100% covering in generic case if somewhere within the program your __DIE__ handler gets overwritten.
Devel::Modlist (also mentioned by slu's answer) - the downside compared to Devel::Cover is that it does NOT seem to be able to aggregate a database across multiple sample runs like Devel::Cover does. On the plus side, it's purpose-built, so has a lot of very useful options (CPAN paths, versions).
Please note that the other module (Module::ScanDeps) does NOT seem to allow you to do runtime analysis based on arbitrary command line arguments (e.g. it seems at first glance to only allow you to execute the program with no arguments) and if that's true, is inferior to all the above 3 methods for any code that may possibly load modules dynamically.
Module::ScanDeps - Recursively scan Perl code for dependencies
Does both static and runtime scanning. Just modules, I don't know of any exact way of verifying what versions from what distributions. You could get old packages from BackPan, or just package your entire chain of local dependencies up with PAR.
You could look at %INC, see http://www.perlmonks.org/?node_id=681911 which also mentions Devel::Modlist
I would definitely use Devel::TraceUse, which also shows a tree of the modules, so it's easy to guess where they are being loaded.