| 1 | =encoding utf8 |
| 2 | |
| 3 | =for comment |
| 4 | Consistent formatting of this file is achieved with: |
| 5 | perl ./Porting/podtidy pod/perlsource.pod |
| 6 | |
| 7 | =head1 NAME |
| 8 | |
| 9 | perlsource - A guide to the Perl source tree |
| 10 | |
| 11 | =head1 DESCRIPTION |
| 12 | |
| 13 | This document describes the layout of the Perl source tree. If you're |
| 14 | hacking on the Perl core, this will help you find what you're looking |
| 15 | for. |
| 16 | |
| 17 | =head1 FINDING YOUR WAY AROUND |
| 18 | |
| 19 | The Perl source tree is big. Here's some of the thing you'll find in |
| 20 | it: |
| 21 | |
| 22 | =head2 C code |
| 23 | |
| 24 | The C source code and header files mostly live in the root of the |
| 25 | source tree. There are a few platform-specific directories which |
| 26 | contain C code. In addition, some of the modules shipped with Perl |
| 27 | include C or XS code. |
| 28 | |
| 29 | See L<perlinterp> for more details on the files that make up the Perl |
| 30 | interpreter, as well as details on how it works. |
| 31 | |
| 32 | =head2 Core modules |
| 33 | |
| 34 | Modules shipped as part of the Perl core live in four subdirectories. |
| 35 | Two of these directories contain modules that live in the core, and two |
| 36 | contain modules that can also be released separately on CPAN. Modules |
| 37 | which can be released on cpan are known as "dual-life" modules. |
| 38 | |
| 39 | =over 4 |
| 40 | |
| 41 | =item * F<lib/> |
| 42 | |
| 43 | This directory contains pure-Perl modules which are only released as |
| 44 | part of the core. This directory contains I<all> of the modules and |
| 45 | their tests, unlike other core modules. |
| 46 | |
| 47 | =item * F<ext/> |
| 48 | |
| 49 | Like F<lib/>, this directory contains modules which are only released |
| 50 | as part of the core. Unlike F<lib/>, however, a module under F<ext/> |
| 51 | generally has a CPAN-style directory- and file-layout and its own |
| 52 | F<Makefile.PL>. There is no expectation that a module under F<ext/> |
| 53 | will work with earlier versions of Perl 5. Hence, such a module may |
| 54 | take full advantage of syntactical and other improvements in Perl 5 |
| 55 | blead. |
| 56 | |
| 57 | =item * F<dist/> |
| 58 | |
| 59 | This directory is for dual-life modules where the blead source is |
| 60 | canonical. Note that some modules in this directory may not yet have |
| 61 | been released separately on CPAN. Modules under F<dist/> should make |
| 62 | an effort to work with earlier versions of Perl 5. |
| 63 | |
| 64 | =item * F<cpan/> |
| 65 | |
| 66 | This directory contains dual-life modules where the CPAN module is |
| 67 | canonical. Do not patch these modules directly! Changes to these |
| 68 | modules should be submitted to the maintainer of the CPAN module. Once |
| 69 | those changes are applied and released, the new version of the module |
| 70 | will be incorporated into the core. |
| 71 | |
| 72 | =back |
| 73 | |
| 74 | For some dual-life modules, it has not yet been determined if the CPAN |
| 75 | version or the blead source is canonical. Until that is done, those |
| 76 | modules should be in F<cpan/>. |
| 77 | |
| 78 | =head2 Tests |
| 79 | |
| 80 | The Perl core has an extensive test suite. If you add new tests (or new |
| 81 | modules with tests), you may need to update the F<t/TEST> file so that |
| 82 | the tests are run. |
| 83 | |
| 84 | =over 4 |
| 85 | |
| 86 | =item * Module tests |
| 87 | |
| 88 | Tests for core modules in the F<lib/> directory are right next to the |
| 89 | module itself. For example, we have F<lib/strict.pm> and |
| 90 | F<lib/strict.t>. |
| 91 | |
| 92 | Tests for modules in F<ext/> and the dual-life modules are in F<t/> |
| 93 | subdirectories for each module, like a standard CPAN distribution. |
| 94 | |
| 95 | =item * F<t/base/> |
| 96 | |
| 97 | Tests for the absolute basic functionality of Perl. This includes |
| 98 | C<if>, basic file reads and writes, simple regexes, etc. These are run |
| 99 | first in the test suite and if any of them fail, something is I<really> |
| 100 | broken. |
| 101 | |
| 102 | =item * F<t/cmd/> |
| 103 | |
| 104 | Tests for basic control structures, C<if/else>, C<while>, subroutines, |
| 105 | etc. |
| 106 | |
| 107 | =item * F<t/comp/> |
| 108 | |
| 109 | Tests for basic issues of how Perl parses and compiles itself. |
| 110 | |
| 111 | =item * F<t/io/> |
| 112 | |
| 113 | Tests for built-in IO functions, including command line arguments. |
| 114 | |
| 115 | =item * F<t/mro/> |
| 116 | |
| 117 | Tests for perl's method resolution order implementations (see L<mro>). |
| 118 | |
| 119 | =item * F<t/op/> |
| 120 | |
| 121 | Tests for perl's built in functions that don't fit into any of the |
| 122 | other directories. |
| 123 | |
| 124 | =item * F<t/opbasic/> |
| 125 | |
| 126 | Tests for perl's built in functions which, like those in F<t/op/>, do |
| 127 | not fit into any of the other directories, but which, in addition, |
| 128 | cannot use F<t/test.pl>,as that program depends on functionality which |
| 129 | the test file itself is testing. |
| 130 | |
| 131 | =item * F<t/re/> |
| 132 | |
| 133 | Tests for regex related functions or behaviour. (These used to live in |
| 134 | t/op). |
| 135 | |
| 136 | =item * F<t/run/> |
| 137 | |
| 138 | Tests for features of how perl actually runs, including exit codes and |
| 139 | handling of PERL* environment variables. |
| 140 | |
| 141 | =item * F<t/uni/> |
| 142 | |
| 143 | Tests for the core support of Unicode. |
| 144 | |
| 145 | =item * F<t/win32/> |
| 146 | |
| 147 | Windows-specific tests. |
| 148 | |
| 149 | =item * F<t/porting/> |
| 150 | |
| 151 | Tests the state of the source tree for various common errors. For |
| 152 | example, it tests that everyone who is listed in the git log has a |
| 153 | corresponding entry in the F<AUTHORS> file. |
| 154 | |
| 155 | =item * F<t/lib/> |
| 156 | |
| 157 | The old home for the module tests, you shouldn't put anything new in |
| 158 | here. There are still some bits and pieces hanging around in here that |
| 159 | need to be moved. Perhaps you could move them? Thanks! |
| 160 | |
| 161 | =item * F<t/x2p> |
| 162 | |
| 163 | A test suite for the s2p converter. |
| 164 | |
| 165 | =back |
| 166 | |
| 167 | =head2 Documentation |
| 168 | |
| 169 | All of the core documentation intended for end users lives in F<pod/>. |
| 170 | Individual modules in F<lib/>, F<ext/>, F<dist/>, and F<cpan/> usually |
| 171 | have their own documentation, either in the F<Module.pm> file or an |
| 172 | accompanying F<Module.pod> file. |
| 173 | |
| 174 | Finally, documentation intended for core Perl developers lives in the |
| 175 | F<Porting/> directory. |
| 176 | |
| 177 | =head2 Hacking tools and documentation |
| 178 | |
| 179 | The F<Porting> directory contains a grab bag of code and documentation |
| 180 | intended to help porters work on Perl. Some of the highlights include: |
| 181 | |
| 182 | =over 4 |
| 183 | |
| 184 | =item * F<check*> |
| 185 | |
| 186 | These are scripts which will check the source things like ANSI C |
| 187 | violations, POD encoding issues, etc. |
| 188 | |
| 189 | =item * F<Maintainers>, F<Maintainers.pl>, and F<Maintainers.pm> |
| 190 | |
| 191 | These files contain information on who maintains which modules. Run |
| 192 | C<perl Porting/Maintainers -M Module::Name> to find out more |
| 193 | information about a dual-life module. |
| 194 | |
| 195 | =item * F<podtidy> |
| 196 | |
| 197 | Tidies a pod file. It's a good idea to run this on a pod file you've |
| 198 | patched. |
| 199 | |
| 200 | =back |
| 201 | |
| 202 | =head2 Build system |
| 203 | |
| 204 | The Perl build system starts with the F<Configure> script in the root |
| 205 | directory. |
| 206 | |
| 207 | Platform-specific pieces of the build system also live in |
| 208 | platform-specific directories like F<win32/>, F<vms/>, etc. |
| 209 | |
| 210 | The F<Configure> script is ultimately responsible for generating a |
| 211 | F<Makefile>. |
| 212 | |
| 213 | The build system that Perl uses is called metaconfig. This system is |
| 214 | maintained separately from the Perl core. |
| 215 | |
| 216 | The metaconfig system has its own git repository. Please see its README |
| 217 | file in L<http://perl5.git.perl.org/metaconfig.git/> for more details. |
| 218 | |
| 219 | The F<Cross> directory contains various files related to |
| 220 | cross-compiling Perl. See F<Cross/README> for more details. |
| 221 | |
| 222 | =head2 F<AUTHORS> |
| 223 | |
| 224 | This file lists everyone who's contributed to Perl. If you submit a |
| 225 | patch, you should add your name to this file as part of the patch. |
| 226 | |
| 227 | =head2 F<MANIFEST> |
| 228 | |
| 229 | The F<MANIFEST> file in the root of the source tree contains a list of |
| 230 | every file in the Perl core, as well as a brief description of each |
| 231 | file. |
| 232 | |
| 233 | You can get an overview of all the files with this command: |
| 234 | |
| 235 | % perl -lne 'print if /^[^\/]+\.[ch]\s+/' MANIFEST |