3 # This module doesn't do much of anything itself, it inherits from the
4 # modules that do the real work. The only real thing it has to do is
5 # figure out which OS-specific module to pull in. Many of the
6 # OS-specific modules don't do anything either - most of the work is
7 # done in Module::Build::Base.
12 use File::Basename ();
14 use Module::Build::Base;
16 use vars qw($VERSION @ISA);
17 @ISA = qw(Module::Build::Base);
19 $VERSION = eval $VERSION;
21 # Okay, this is the brute-force method of finding out what kind of
22 # platform we're on. I don't know of a systematic way. These values
23 # came from the latest (bleadperl) perlport.pod.
66 # Inserts the given module into the @ISA hierarchy between
67 # Module::Build and its immediate parent
68 sub _interpose_module {
69 my ($self, $mod) = @_;
75 while (@{"${top_class}::ISA"}) {
76 last if ${"${top_class}::ISA"}[0] eq $ISA[0];
77 $top_class = ${"${top_class}::ISA"}[0];
80 @{"${top_class}::ISA"} = @ISA;
84 if (grep {-e File::Spec->catfile($_, qw(Module Build Platform), $^O) . '.pm'} @INC) {
85 __PACKAGE__->_interpose_module("Module::Build::Platform::$^O");
87 } elsif (exists $OSTYPES{$^O}) {
88 __PACKAGE__->_interpose_module("Module::Build::Platform::$OSTYPES{$^O}");
91 warn "Unknown OS type '$^O' - using default settings\n";
94 sub os_type { $OSTYPES{$^O} }
103 Module::Build - Build and install Perl modules
108 Standard process for building & installing modules:
115 Or, if you're on a platform (like DOS or Windows) that doesn't require
116 the "./" notation, you can do this:
126 C<Module::Build> is a system for building, testing, and installing
127 Perl modules. It is meant to be an alternative to
128 C<ExtUtils::MakeMaker>. Developers may alter the behavior of the
129 module through subclassing in a much more straightforward way than
130 with C<MakeMaker>. It also does not require a C<make> on your system
131 - most of the C<Module::Build> code is pure-perl and written in a very
132 cross-platform way. In fact, you don't even need a shell, so even
133 platforms like MacOS (traditional) can use it fairly easily. Its only
134 prerequisites are modules that are included with perl 5.6.0, and it
135 works fine on perl 5.005 if you can install a few additional modules.
137 See L<"MOTIVATIONS"> for more comparisons between C<ExtUtils::MakeMaker>
138 and C<Module::Build>.
140 To install C<Module::Build>, and any other module that uses
141 C<Module::Build> for its installation process, do the following:
143 perl Build.PL # 'Build.PL' script creates the 'Build' script
144 ./Build # Need ./ to ensure we're using this "Build" script
145 ./Build test # and not another one that happens to be in the PATH
148 This illustrates initial configuration and the running of three
149 'actions'. In this case the actions run are 'build' (the default
150 action), 'test', and 'install'. Other actions defined so far include:
158 distcheck pure_install
165 fakeinstall testpodcoverage
170 You can run the 'help' action for a complete list of actions.
173 =head1 GUIDE TO DOCUMENTATION
175 The documentation for C<Module::Build> is broken up into three sections:
179 =item General Usage (L<Module::Build>)
181 This is the document you are currently reading. It describes basic
182 usage and background information. Its main purpose is to assist the
183 user who wants to learn how to invoke and control C<Module::Build>
184 scripts at the command line.
186 =item Authoring Reference (L<Module::Build::Authoring>)
188 This document describes the C<Module::Build> API for authors who are
189 writing F<Build.PL> scripts for a distribution or controlling
190 C<Module::Build> processes programmatically. It describes the
191 methods available as well as providing general information on
192 subclassing C<Module::Build> to alter and extend its behavior. Also,
193 there is a section on controlling the Build process from other
194 scripts, including how to construct an object and how to invoke
195 actions through it from an external script.
197 =item Cookbook (L<Module::Build::Cookbook>)
199 This document demonstrates how to accomplish many common tasks. It
200 covers general command line usage and authoring of F<Build.PL>
201 scripts. Includes working examples.
208 There are some general principles at work here. First, each task when
209 building a module is called an "action". These actions are listed
210 above; they correspond to the building, testing, installing,
211 packaging, etc., tasks.
213 Second, arguments are processed in a very systematic way. Arguments
214 are always key=value pairs. They may be specified at C<perl Build.PL>
215 time (i.e. C<perl Build.PL destdir=/my/secret/place>), in which case
216 their values last for the lifetime of the C<Build> script. They may
217 also be specified when executing a particular action (i.e.
218 C<Build test verbose=1>), in which case their values last only for the
219 lifetime of that command. Per-action command line parameters take
220 precedence over parameters specified at C<perl Build.PL> time.
222 The build process also relies heavily on the C<Config.pm> module, and
223 all the key=value pairs in C<Config.pm> are available in
225 C<< $self->{config} >>. If the user wishes to override any of the
226 values in C<Config.pm>, she may specify them like so:
228 perl Build.PL --config cc=gcc --config ld=gcc
230 The following build actions are provided by default.
236 If you run the C<Build> script without any arguments, it runs the
237 C<build> action, which in turn runs the C<code> and C<docs> actions.
239 This is analogous to the MakeMaker 'make all' target.
241 =item testpodcoverage
243 This checks the pod coverage of the distribution and
244 produces C<Test::Harness>-style output. If you are a module author,
245 this is useful to run before creating a new release.
249 This action will clean up any files that the build process may have
250 created, including the C<blib/> directory (but not including the
251 C<_build/> directory and the C<Build> script itself).
255 This action builds your codebase.
257 By default it just creates a C<blib/> directory and copies any C<.pm>
258 and C<.pod> files from your C<lib/> directory into the C<blib/>
259 directory. It also compiles any C<.xs> files from C<lib/> and places
260 them in C<blib/>. Of course, you need a working C compiler (probably
261 the same one that built perl itself) for the compilation to work
264 The C<code> action also runs any C<.PL> files in your F<lib/>
265 directory. Typically these create other files, named the same but
266 without the C<.PL> ending. For example, a file F<lib/Foo/Bar.pm.PL>
267 could create the file F<lib/Foo/Bar.pm>. The C<.PL> files are
268 processed first, so any C<.pm> files (or other kinds that we deal
269 with) will get copied correctly.
277 This action will compare the files about to be installed with their
278 installed counterparts. For .pm and .pod files, a diff will be shown
279 (this currently requires a 'diff' program to be in your PATH). For
280 other files like compiled binary files, we simply report whether they
283 A C<flags> parameter may be passed to the action, which will be passed
284 to the 'diff' program. Consult your 'diff' documentation for the
285 parameters it will accept - a good one is C<-u>:
287 ./Build diff flags=-u
291 This action is helpful for module authors who want to package up their
292 module for source distribution through a medium like CPAN. It will create a
293 tarball of the files listed in F<MANIFEST> and compress the tarball using
296 By default, this action will use the external C<tar> and C<gzip>
297 executables on Unix-like platforms, and the C<Archive::Tar> module
298 elsewhere. However, you can force it to use whatever executable you
299 want by supplying an explicit C<tar> (and optional C<gzip>) parameter:
301 ./Build dist --tar C:\path\to\tar.exe --gzip C:\path\to\zip.exe
305 Reports which files are in the build directory but not in the
306 F<MANIFEST> file, and vice versa. (See L<manifest> for details.)
310 Performs the 'realclean' action and then the 'distcheck' action.
314 Creates a "distribution directory" named C<$dist_name-$dist_version>
315 (if that directory already exists, it will be removed first), then
316 copies all the files listed in the F<MANIFEST> file to that directory.
317 This directory is what the distribution tarball is created from.
321 Creates the F<META.yml> file that describes the distribution.
323 F<META.yml> is a file containing various bits of "metadata" about the
324 distribution. The metadata includes the distribution name, version,
325 abstract, prerequisites, license, and various other data about the
326 distribution. This file is created as F<META.yml> in YAML format, so
327 the C<YAML> module must be installed in order to create it. The
328 F<META.yml> file must also be listed in F<MANIFEST> - if it's not, a
329 warning will be issued.
331 The current version of the F<META.yml> specification can be found at
332 L<http://module-build.sourceforge.net/META-spec-v1.2.html>
336 Uses C<Module::Signature> to create a SIGNATURE file for your
337 distribution, and adds the SIGNATURE file to the distribution's
342 Performs the 'distdir' action, then switches into that directory and
343 runs a C<perl Build.PL>, followed by the 'build' and 'test' actions in
348 This will generate documentation (e.g. Unix man pages and html
349 documents) for any installable items under B<blib/> that
350 contain POD. If there are no C<bindoc> or C<libdoc> installation
351 targets defined (as will be the case on systems that don't support
352 Unix manpages) no action is taken for manpages. If there are no
353 C<binhtml> or C<libhtml> installation targets defined no action is
354 taken for html documents.
358 This is just like the C<install> action, but it won't actually do
359 anything, it will just report what it I<would> have done if you had
360 actually run the C<install> action.
364 This action will simply print out a message that is meant to help you
365 use the build process. It will show you a list of available build
368 With an optional argument specifying an action name (e.g. C<Build help
369 test>), the 'help' action will show you any POD documentation it can
370 find for that action.
374 This will generate HTML documentation for any binary or library files
375 under B<blib/> that contain POD. The HTML documentation will only be
376 installed if the install paths can be determined from values in
377 C<Config.pm>. You can also supply or override install paths on the
378 command line by specifying C<install_path> values for the C<binhtml>
379 and/or C<libhtml> installation targets.
383 This action will use C<ExtUtils::Install> to install the files from
384 C<blib/> into the system. See L<INSTALL PATHS>
385 for details about how Module::Build determines where to install
386 things, and how to influence this process.
388 If you want the installation process to look around in C<@INC> for
389 other versions of the stuff you're installing and try to delete it,
390 you can use the C<uninst> parameter, which tells C<ExtUtils::Install> to
393 ./Build install uninst=1
395 This can be a good idea, as it helps prevent multiple versions of a
396 module from being present on your system, which can be a confusing
401 This is an action intended for use by module authors, not people
402 installing modules. It will bring the F<MANIFEST> up to date with the
403 files currently present in the distribution. You may use a
404 F<MANIFEST.SKIP> file to exclude certain files or directories from
405 inclusion in the F<MANIFEST>. F<MANIFEST.SKIP> should contain a bunch
406 of regular expressions, one per line. If a file in the distribution
407 directory matches any of the regular expressions, it won't be included
410 The following is a reasonable F<MANIFEST.SKIP> starting point, you can
411 add your own stuff to it:
421 See the L<distcheck> and L<skipcheck> actions if you want to find out
422 what the C<manifest> action would do, without actually doing anything.
426 This will generate man pages for any binary or library files under
427 B<blib/> that contain POD. The man pages will only be installed if the
428 install paths can be determined from values in C<Config.pm>. You can
429 also supply or override install paths by specifying there values on
430 the command line with the C<bindoc> and C<libdoc> installation
435 Build a PPD file for your distribution.
437 This action takes an optional argument C<codebase> which is used in
438 the generated ppd file to specify the (usually relative) URL of the
439 distribution. By default, this value is the distribution name without
440 any path information.
444 ./Build ppd --codebase "MSWin32-x86-multi-thread/Module-Build-0.21.tar.gz"
448 Generates a PPM binary distribution and a PPD description file. This
449 action also invokes the 'ppd' action, so it can accept the same
450 C<codebase> argument described under that action.
452 This uses the same mechanism as the C<dist> action to tar & zip its
453 output, so you can supply C<tar> and/or C<gzip> parameters to affect
458 This action prints out a list of all prerequisites, the versions required, and
459 the versions actually installed. This can be useful for reviewing the
460 configuration of your system prior to a build, or when compiling data to send
465 This action is identical to the C<install> action. In the future,
466 though, if C<install> starts writing to the file file
467 F<$(INSTALLARCHLIB)/perllocal.pod>, C<pure_install> won't, and that
468 will be the only difference between them.
472 This action is just like the C<clean> action, but also removes the
473 C<_build> directory and the C<Build> script. If you run the
474 C<realclean> action, you are essentially starting over, so you will
475 have to re-create the C<Build> script again.
479 Reports which files are skipped due to the entries in the
480 F<MANIFEST.SKIP> file (See L<manifest> for details)
484 This will use C<Test::Harness> to run any regression tests and report
485 their results. Tests can be defined in the standard places: a file
486 called C<test.pl> in the top-level directory, or several files ending
487 with C<.t> in a C<t/> directory.
489 If you want tests to be 'verbose', i.e. show details of test execution
490 rather than just summary information, pass the argument C<verbose=1>.
492 If you want to run tests under the perl debugger, pass the argument
495 In addition, if a file called C<visual.pl> exists in the top-level
496 directory, this file will be executed as a Perl script and its output
497 will be shown to the user. This is a good place to put speed tests or
498 other tests that don't use the C<Test::Harness> format for output.
500 To override the choice of tests to run, you may pass a C<test_files>
501 argument whose value is a whitespace-separated list of test scripts to
502 run. This is especially useful in development, when you only want to
503 run a single test to see whether you've squashed a certain bug yet:
505 ./Build test --test_files t/something_failing.t
507 You may also pass several C<test_files> arguments separately:
509 ./Build test --test_files t/one.t --test_files t/two.t
511 or use a C<glob()>-style pattern:
513 ./Build test --test_files 't/01-*.t'
517 Runs the C<test> action using C<Devel::Cover>, generating a
518 code-coverage report showing which parts of the code were actually
519 exercised during the tests.
521 To pass options to C<Devel::Cover>, set the C<$DEVEL_COVER_OPTIONS>
522 environment variable:
524 DEVEL_COVER_OPTIONS=-ignore,Build ./Build testcover
528 This is a synonym for the 'test' action with the C<debugger=1>
533 This checks all the files described in the C<docs> action and
534 produces C<Test::Harness>-style output. If you are a module author,
535 this is useful to run before creating a new release.
539 ** Note: since C<only.pm> is so new, and since we just recently added
540 support for it here too, this feature is to be considered
543 If you have the C<only.pm> module installed on your system, you can
544 use this action to install a module into the version-specific library
545 trees. This means that you can have several versions of the same
546 module installed and C<use> a specific one like this:
548 use only MyModule => 0.55;
550 To override the default installation libraries in C<only::config>,
551 specify the C<versionlib> parameter when you run the C<Build.PL> script:
553 perl Build.PL --versionlib /my/version/place/
555 To override which version the module is installed as, specify the
556 C<versionlib> parameter when you run the C<Build.PL> script:
558 perl Build.PL --version 0.50
560 See the C<only.pm> documentation for more information on
561 version-specific installs.
568 =head2 Command Line Options
570 The following options can be used during any invocation of C<Build.PL>
571 or the Build script, during any action. For information on other
572 options specific to an action, see the documentation for the
575 NOTE: There is some preliminary support for options to use the more
576 familiar long option style. Most options can be preceded with the
577 C<--> long option prefix, and the underscores changed to dashes
578 (e.g. --use-rcfile). Additionally, the argument to boolean options is
579 optional, and boolean options can be negated by prefixing them with
580 'no' or 'no-' (e.g. --noverbose or --no-verbose).
586 Suppress informative messages on output.
590 Load the F<~/.modulebuildrc> option file. This option can be set to
591 false to prevent the custom resource file from being loaded.
595 Display extra information about the Build on output.
600 =head2 Default Options File (F<.modulebuildrc>)
602 When Module::Build starts up, it will look for a file,
603 F<$ENV{HOME}/.modulebuildrc>. If the file exists, the options
604 specified there will be used as defaults, as if they were typed on the
605 command line. The defaults can be overridden by specifying new values
608 The action name must come at the beginning of the line, followed by any
609 amount of whitespace and then the options. Options are given the same
610 as they would be on the command line. They can be separated by any
611 amount of whitespace, including newlines, as long there is whitespace at
612 the beginning of each continued line. Anything following a hash mark (C<#>)
613 is considered a comment, and is stripped before parsing. If more than
614 one line begins with the same action name, those lines are merged into
617 Besides the regular actions, there are two special pseudo-actions: the
618 key C<*> (asterisk) denotes any global options that should be applied
619 to all actions, and the key 'Build_PL' specifies options to be applied
620 when you invoke C<perl Build.PL>.
622 * verbose=1 # global options
624 install --install_base /home/ken
625 --install_path html=/home/ken/docs/html
627 If you wish to locate your resource file in a different location, you
628 can set the environment variable 'MODULEBUILDRC' to the complete
629 absolute path of the file containing your options.
634 When you invoke Module::Build's C<build> action, it needs to figure
635 out where to install things. The nutshell version of how this works
636 is that default installation locations are determined from
637 F<Config.pm>, and they may be overridden by using the C<install_path>
638 parameter. An C<install_base> parameter lets you specify an
639 alternative installation root like F</home/foo>, and a C<destdir> lets
640 you specify a temporary installation directory like F</tmp/install> in
641 case you want to create bundled-up installable packages.
643 Natively, Module::Build provides default installation locations for
644 the following types of installable items:
650 Usually pure-Perl module files ending in F<.pm>.
654 "Architecture-dependent" module files, usually produced by compiling
655 XS, Inline, or similar code.
659 Programs written in pure Perl. In order to improve reuse, try to make
660 these as small as possible - put the code into modules whenever
665 "Architecture-dependent" executable programs, i.e. compiled C code or
666 something. Pretty rare to see this in a perl distribution, but it
671 Documentation for the stuff in C<script> and C<bin>. Usually
672 generated from the POD in those files. Under Unix, these are manual
673 pages belonging to the 'man1' category.
677 Documentation for the stuff in C<lib> and C<arch>. This is usually
678 generated from the POD in F<.pm> files. Under Unix, these are manual
679 pages belonging to the 'man3' category.
683 This is the same as C<bindoc> above, but applies to html documents.
687 This is the same as C<bindoc> above, but applies to html documents.
691 Four other parameters let you control various aspects of how
692 installation paths are determined:
698 The default destinations for these installable things come from
699 entries in your system's C<Config.pm>. You can select from three
700 different sets of default locations by setting the C<installdirs>
701 parameter as follows:
703 'installdirs' set to:
706 uses the following defaults from Config.pm:
708 lib => installprivlib installsitelib installvendorlib
709 arch => installarchlib installsitearch installvendorarch
710 script => installscript installsitebin installvendorbin
711 bin => installbin installsitebin installvendorbin
712 bindoc => installman1dir installsiteman1dir installvendorman1dir
713 libdoc => installman3dir installsiteman3dir installvendorman3dir
714 binhtml => installhtml1dir installsitehtml1dir installvendorhtml1dir [*]
715 libhtml => installhtml3dir installsitehtml3dir installvendorhtml3dir [*]
717 * Under some OS (eg. MSWin32) the destination for html documents is
718 determined by the C<Config.pm> entry C<installhtmldir>.
720 The default value of C<installdirs> is "site". If you're creating
721 vendor distributions of module packages, you may want to do something
724 perl Build.PL --installdirs vendor
728 ./Build install --installdirs vendor
730 If you're installing an updated version of a module that was included
731 with perl itself (i.e. a "core module"), then you may set
732 C<installdirs> to "core" to overwrite the module in its present
735 (Note that the 'script' line is different from MakeMaker -
736 unfortunately there's no such thing as "installsitescript" or
737 "installvendorscript" entry in C<Config.pm>, so we use the
738 "installsitebin" and "installvendorbin" entries to at least get the
739 general location right. In the future, if C<Config.pm> adds some more
740 appropriate entries, we'll start using those.)
744 Once the defaults have been set, you can override them.
746 On the command line, that would look like this:
748 perl Build.PL --install_path lib=/foo/lib --install_path arch=/foo/lib/arch
752 ./Build install --install_path lib=/foo/lib --install_path arch=/foo/lib/arch
756 You can also set the whole bunch of installation paths by supplying the
757 C<install_base> parameter to point to a directory on your system. For
758 instance, if you set C<install_base> to "/home/ken" on a Linux
759 system, you'll install as follows:
761 lib => /home/ken/lib/perl5
762 arch => /home/ken/lib/perl5/i386-linux
763 script => /home/ken/bin
765 bindoc => /home/ken/man/man1
766 libdoc => /home/ken/man/man3
767 binhtml => /home/ken/html
768 libhtml => /home/ken/html
770 Note that this is I<different> from how MakeMaker's C<PREFIX>
771 parameter works. See L</"Why PREFIX is not recommended"> for more
772 details. C<install_base> just gives you a default layout under the
773 directory you specify, which may have little to do with the
774 C<installdirs=site> layout.
776 The exact layout under the directory you specify may vary by system -
777 we try to do the "sensible" thing on each platform.
781 If you want to install everything into a temporary directory first
782 (for instance, if you want to create a directory tree that a package
783 manager like C<rpm> or C<dpkg> could create a package from), you can
784 use the C<destdir> parameter:
786 perl Build.PL --destdir /tmp/foo
790 ./Build install --destdir /tmp/foo
792 This will effectively install to "/tmp/foo/$sitelib",
793 "/tmp/foo/$sitearch", and the like, except that it will use
794 C<File::Spec> to make the pathnames work correctly on whatever
795 platform you're installing on.
799 =head2 About PREFIX Support
801 First, it is necessary to understand the original idea behind
802 C<PREFIX>. If, for example, the default installation locations for
803 your machine are F</usr/local/lib/perl5/5.8.5> for modules,
804 F</usr/local/bin> for executables, F</usr/local/man/man1> and
805 F</usr/local/man/man3> for manual pages, etc., then they all share the
806 same "prefix" F</usr/local>. MakeMaker's C<PREFIX> mechanism was
807 intended as a way to change an existing prefix that happened to occur
808 in all those paths - essentially a C<< s{/usr/local}{/foo/bar} >> for
811 However, the real world is more complicated than that. The C<PREFIX>
812 idea is fundamentally broken when your machine doesn't jibe with
813 C<PREFIX>'s worldview.
818 =item Why PREFIX is not recommended
824 Many systems have Perl configs that make little sense with PREFIX.
825 For example, OS X, where core modules go in
826 F</System/Library/Perl/...>, user-installed modules go in
827 F</Library/Perl/...>, and man pages go in F</usr/share/man/...>. The
828 PREFIX is thus set to F</>. Install L<Foo::Bar> on OS X with
829 C<PREFIX=/home/spurkis> and you get things like
830 F</home/spurkis/Library/Perl/5.8.1/Foo/Bar.pm> and
831 F</home/spurkis/usr/share/man/man3/Foo::Bar.3pm>. Not too pretty.
833 The problem is not limited to Unix-like platforms, either - on Windows
834 builds (e.g. ActiveState perl 5.8.0), we have user-installed modules
835 going in F<C:\Perl\site\lib>, user-installed executables going in
836 F<C:\Perl\bin>, and PREFIX=F<C:\Perl\site>. The prefix just doesn't
837 apply neatly to the executables.
841 The PREFIX logic is too complicated and hard to predict for the user.
842 It's hard to document what exactly is going to happen. You can't give
843 a user simple instructions like "run perl Makefile.PL PREFIX=~ and
844 then set PERL5LIB=~/lib/perl5".
848 The results from PREFIX will change if your configuration of Perl
849 changes (for example, if you upgrade Perl). This means your modules
850 will end up in different places.
854 The results from PREFIX can change with different releases of
855 MakeMaker. The logic of PREFIX is subtle and it has been altered in
856 the past (mostly to limit damage in the many "edge cases" when its
857 behavior was undesirable).
861 PREFIX imposes decisions made by the person who configured Perl onto
862 the person installing a module. The person who configured Perl could
863 have been you or it could have been some guy at Redhat.
868 =item Alternatives to PREFIX
870 Module::Build offers L</install_base> as a simple, predictable, and
871 user-configurable alternative to ExtUtils::MakeMaker's C<PREFIX>.
872 What's more, MakeMaker will soon accept C<INSTALL_BASE> -- we strongly
873 urge you to make the switch.
875 Here's a quick comparison of the two when installing modules to your
876 home directory on a unix box:
880 % perl Makefile.PL PREFIX=/home/spurkis
881 PERL5LIB=/home/spurkis/lib/perl5/5.8.5:/home/spurkis/lib/perl5/site_perl/5.8.5
882 PATH=/home/spurkis/bin
883 MANPATH=/home/spurkis/man
887 % perl Build.PL install_base=/home/spurkis
888 PERL5LIB=/home/spurkis/lib/perl5
889 PATH=/home/spurkis/bin
890 MANPATH=/home/spurkis/man
892 [*] Note that MakeMaker's behaviour cannot be guaranteed in even this
893 common scenario, and differs among different versions of MakeMaker.
895 In short, using C<install_base> is similar to the following MakeMaker usage:
897 perl Makefile.PL PREFIX=/home/spurkis LIB=/home/spurkis/lib/perl5
899 See L</INSTALL PATHS> for details on other
900 installation options available and how to configure them.
907 There are several reasons I wanted to start over, and not just fix
908 what I didn't like about MakeMaker:
914 I don't like the core idea of MakeMaker, namely that C<make> should be
915 involved in the build process. Here are my reasons:
921 When a person is installing a Perl module, what can you assume about
922 their environment? Can you assume they have C<make>? No, but you can
923 assume they have some version of Perl.
927 When a person is writing a Perl module for intended distribution, can
928 you assume that they know how to build a Makefile, so they can
929 customize their build process? No, but you can assume they know Perl,
930 and could customize that way.
934 For years, these things have been a barrier to people getting the
935 build/install process to do what they want.
939 There are several architectural decisions in MakeMaker that make it
940 very difficult to customize its behavior. For instance, when using
941 MakeMaker you do C<use ExtUtils::MakeMaker>, but the object created in
942 C<WriteMakefile()> is actually blessed into a package name that's
943 created on the fly, so you can't simply subclass
944 C<ExtUtils::MakeMaker>. There is a workaround C<MY> package that lets
945 you override certain MakeMaker methods, but only certain explicitly
946 preselected (by MakeMaker) methods can be overridden. Also, the method
947 of customization is very crude: you have to modify a string containing
948 the Makefile text for the particular target. Since these strings
949 aren't documented, and I<can't> be documented (they take on different
950 values depending on the platform, version of perl, version of
951 MakeMaker, etc.), you have no guarantee that your modifications will
952 work on someone else's machine or after an upgrade of MakeMaker or
957 It is risky to make major changes to MakeMaker, since it does so many
958 things, is so important, and generally works. C<Module::Build> is an
959 entirely separate package so that I can work on it all I want, without
960 worrying about backward compatibility.
964 Finally, Perl is said to be a language for system administration.
965 Could it really be the case that Perl isn't up to the task of building
966 and installing software? Even if that software is a bunch of stupid
967 little C<.pm> files that just need to be copied from one place to
968 another? My sense was that we could design a system to accomplish
969 this in a flexible, extensible, and friendly manner. Or die trying.
976 The current method of relying on time stamps to determine whether a
977 derived file is out of date isn't likely to scale well, since it
978 requires tracing all dependencies backward, it runs into problems on
979 NFS, and it's just generally flimsy. It would be better to use an MD5
980 signature or the like, if available. See C<cons> for an example.
982 - append to perllocal.pod
983 - add a 'plugin' functionality
988 Ken Williams <kwilliams@cpan.org>
990 Development questions, bug reports, and patches should be sent to the
991 Module-Build mailing list at <module-build-general@lists.sourceforge.net>.
993 Bug reports are also welcome at
994 <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Module-Build>.
996 An anonymous CVS repository containing the latest development version
997 is available; see <http://sourceforge.net/cvs/?group_id=45731> for the
998 details of how to access it.
1003 Copyright (c) 2001-2005 Ken Williams. All rights reserved.
1005 This library is free software; you can redistribute it and/or
1006 modify it under the same terms as Perl itself.
1011 perl(1), Module::Build::Cookbook(3), Module::Build::Authoring(3),
1012 ExtUtils::MakeMaker(3), YAML(3)
1014 F<META.yml> Specification:
1015 L<http://module-build.sourceforge.net/META-spec-v1.2.html>
1017 L<http://www.dsmit.com/cons/>