39b46a5398
The capital Greek letter sigma (Σ) should be lowercased as σ except when it appears at the end of a word; in that case, it should be lowercased as the special form ς. This rule is included in the Unicode data file SpecialCasing.txt. The condition for applying the rule is called "Final_Sigma" and is defined in Unicode technical report 21. The rule is: • For the special casing form to apply, the capital letter sigma must be preceded by 0 or more "case-ignorable" characters, preceded by at least 1 "cased" character. • Further, capital sigma must NOT be followed by 0 or more case-ignorable characters and then at least 1 cased character. "Case-ignorable" characters include certain punctuation marks, like the apostrophe, as well as various accent marks. There are actually close to 500 different case-ignorable characters, including accent marks from Cyrillic, Hebrew, Armenian, Arabic, Syriac, Bengali, Gujarati, Telugu, Tibetan, and many other alphabets. This category also includes zero-width spaces, codepoints which indicate RTL/LTR text direction, certain musical symbols, etc. Since the rule involves scanning over "0 or more" of such case-ignorable characters, it may be necessary to scan arbitrarily far to the left and right of capital sigma to determine whether the special lowercase form should be used or not. However, since we are trying to be both memory-efficient and CPU-efficient, this implementation limits how far to the left we will scan. Generally, we scan up to 63 characters to the left looking for a "cased" character, but not more. When scanning to the right, we go up to the end of the string if necessary, even if it means scanning over thousands of characters. Anyways, it is almost impossible to imagine that natural text will include "words" with more than 63 successive apostrophes (for example) followed by a capital sigma. Closes GH-8096.
The PHP Interpreter
PHP is a popular general-purpose scripting language that is especially suited to web development. Fast, flexible and pragmatic, PHP powers everything from your blog to the most popular websites in the world. PHP is distributed under the PHP License v3.01.
Documentation
The PHP manual is available at php.net/docs.
Installation
Prebuilt packages and binaries
Prebuilt packages and binaries can be used to get up and running fast with PHP.
For Windows, the PHP binaries can be obtained from
windows.php.net. After extracting the archive the
*.exe files are ready to use.
For other systems, see the installation chapter.
Building PHP source code
For Windows, see Build your own PHP on Windows.
For a minimal PHP build from Git, you will need autoconf, bison, and re2c. For a default build, you will additionally need libxml2 and libsqlite3.
On Ubuntu, you can install these using:
sudo apt install -y pkg-config build-essential autoconf bison re2c \
libxml2-dev libsqlite3-dev
On Fedora, you can install these using:
sudo dnf install re2c bison autoconf make libtool ccache libxml2-devel sqlite-devel
Generate configure:
./buildconf
Configure your build. --enable-debug is recommended for development, see
./configure --help for a full list of options.
# For development
./configure --enable-debug
# For production
./configure
Build PHP. To speed up the build, specify the maximum number of jobs using -j:
make -j4
The number of jobs should usually match the number of available cores, which
can be determined using nproc.
Testing PHP source code
PHP ships with an extensive test suite, the command make test is used after
successful compilation of the sources to run this test suite.
It is possible to run tests using multiple cores by setting -jN in
TEST_PHP_ARGS:
make TEST_PHP_ARGS=-j4 test
Shall run make test with a maximum of 4 concurrent jobs: Generally the maximum
number of jobs should not exceed the number of cores available.
The qa.php.net site provides more detailed info about testing and quality assurance.
Installing PHP built from source
After a successful build (and test), PHP may be installed with:
make install
Depending on your permissions and prefix, make install may need super user
permissions.
PHP extensions
Extensions provide additional functionality on top of PHP. PHP consists of many essential bundled extensions. Additional extensions can be found in the PHP Extension Community Library - PECL.
Contributing
The PHP source code is located in the Git repository at github.com/php/php-src. Contributions are most welcome by forking the repository and sending a pull request.
Discussions are done on GitHub, but depending on the topic can also be relayed to the official PHP developer mailing list internals@lists.php.net.
New features require an RFC and must be accepted by the developers. See Request for comments - RFC and Voting on PHP features for more information on the process.
Bug fixes don't require an RFC. If the bug has a GitHub issue, reference it in
the commit message using GH-NNNNNN. Use #NNNNNN for tickets in the old
bugs.php.net bug tracker.
Fix GH-7815: php_uname doesn't recognise latest Windows versions
Fix #55371: get_magic_quotes_gpc() throws deprecation warning
See Git workflow for details on how pull requests are merged.
Guidelines for contributors
See further documents in the repository for more information on how to contribute:
Credits
For the list of people who've put work into PHP, please see the PHP credits page.