PHP

PHP was released in 1995 by Rasmus Lerdorf as “Personal Home Page Tools,” a set of scripts for tracking visits to his online résumé. It grew into a language for building web pages on the server, and it now runs WordPress, Wikipedia’s MediaWiki, and a large share of the web. The name now stands for “PHP: Hypertext Preprocessor.”

A PHP file starts with <?php, and every variable name starts with $. PHP’s main collection type is the array, which is an ordered map: with keys 0, 1, 2, and so on it acts as a list, and with string keys it acts as a dictionary. The standard library is large and built in, from array_sum and usort to str_getcsv. Packages from Composer, PHP’s package manager, aren’t installed here. Every program here starts with declare(strict_types=1), and the run script fails the run on any warning or deprecation notice.

Quirks

• / gives a whole number only when the division is exact: 10 / 2 is the integer 5, while 10 / 3 is 3.3333333333333335. intdiv(-7, 2) is −3, and -7 % 3 is −1.
• sort compares numeric strings as numbers, so "10", "9", and "1" sort to 1, 9, 10. Add a string such as "abc" and it goes last.
• == converts numeric strings: "1" == "01" and "10" == "1e1" are both true. === compares without converting.
• The strings "0" and "" are false, but "0.0", "00", and " " are true.
• Array keys are converted: $h["1"] and $h[1] are the same entry, and a float key such as 1.5 is cut to 1, with a deprecation notice.
• sort throws away the keys and numbers the values from 0 again.
• "5 apples" + 2 is 7, with a warning.
• max([]) stops the program with a ValueError, while array_sum([]) is 0.
• An integer that overflows becomes a float: PHP_INT_MAX + 1 is 9.223372036854776E+18.
• round(2.5) is 3 and round(-2.5) is −3: halves round away from zero.
• str_getcsv raises a deprecation notice in PHP 8.4 unless you pass its escape argument, because its default is going to change.

git clone https://github.com/qnixon/dswithx.git
cd dswithx
python3 harness/run_tests.py --language php