Initial commit: Pi calculation benchmark with 34 languages

- Added implementations for: bash, brainfuck, c, cpp, crystal, csharp, d, dart, elixir, erlang, fortran, go, haskell, java, javascript, julia, kotlin, objective-c, scala, typescript, lua, nim, odin, perl, php, python, r, ruby, rust, swift, zig, assembly, vimscript, wolfram
- All implementations use Machin's formula: π/4 = 4*arctan(1/5) - arctan(1/239)
- Build system with ./build.sh, test system with ./test.sh
- Performance testing with ./run_all.sh
- Comprehensive README.md explaining performance differences
- Test framework verifies correctness against known π values

php/src/PiTest.php

@@ -0,0 +1,63 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+class PiTest extends TestCase
+{
+    private const SCRIPT_PATH = '/Users/einand/Code/test/php/print_hej.php';
+    
+    private function runScript(?string $decimals = null): string
+    {
+        $cmd = ['php', self::SCRIPT_PATH];
+        if ($decimals !== null) {
+            $cmd[] = $decimals;
+        }
+        
+        $output = [];
+        exec(implode(' ', $cmd), $output);
+        return trim(implode("\n", $output));
+    }
+    
+    public function test10Decimals(): void
+    {
+        $result = $this->runScript('10');
+        $expected = '3.1415926535';
+        $this->assertEquals($expected, $result);
+    }
+    
+    public function test5Decimals(): void
+    {
+        $result = $this->runScript('5');
+        $expected = '3.14159';
+        $this->assertEquals($expected, $result);
+    }
+    
+    public function test1Decimal(): void
+    {
+        $result = $this->runScript('1');
+        $expected = '3.1';
+        $this->assertEquals($expected, $result);
+    }
+    
+    public function test100Decimals(): void
+    {
+        $result = $this->runScript('100');
+        $expected = '3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679';
+        $this->assertEquals($expected, $result);
+    }
+    
+    public function testDefault100Decimals(): void
+    {
+        $result = $this->runScript();
+        $expected = '3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679';
+        $this->assertEquals($expected, $result);
+    }
+    
+    public function test10000Decimals(): void
+    {
+        $result = $this->runScript('10000');
+        // Check length: "3." + 10000 digits = 10002 characters
+        $this->assertEquals(10002, strlen($result));
+        $this->assertTrue(strpos($result, '3.14159') === 0);
+    }
+}

php/src/print_hej.php

@@ -0,0 +1,54 @@
+<?php
+
+// Calculate arctan(1/x) using Taylor series
+function arctan($x, $decimals) {
+    $scale = bcpow('10', $decimals + 10);
+    $xSquared = bcmul($x, $x);
+    
+    $result = '0';
+    $term = bcdiv($scale, $x);
+    
+    $n = 0;
+    while (bccomp($term, '0') != 0 && $n < $decimals * 3) {
+        $divisor = (string)(2 * $n + 1);
+        $contrib = bcdiv($term, $divisor);
+        
+        if ($n % 2 == 0) {
+            $result = bcadd($result, $contrib);
+        } else {
+            $result = bcsub($result, $contrib);
+        }
+        
+        $term = bcdiv($term, $xSquared);
+        $n++;
+        
+        if ($n > $decimals * 2) break;
+    }
+    
+    return $result;
+}
+
+// Calculate pi using Machin's formula
+function calculate_pi($decimals) {
+    $atan1_5 = arctan(5, $decimals);
+    $atan1_239 = arctan(239, $decimals);
+    
+    return bcsub(bcmul($atan1_5, '16'), bcmul($atan1_239, '4'));
+}
+
+// Format pi with decimal point
+function format_pi($pi, $decimals) {
+    $piStr = $pi;
+    while (strlen($piStr) < $decimals + 10) {
+        $piStr = '0' . $piStr;
+    }
+    return '3.' . substr($piStr, 1, $decimals);
+}
+
+// Main
+$decimals = isset($argv[1]) ? (int)$argv[1] : 100;
+if ($decimals <= 0) $decimals = 100;
+
+$pi = calculate_pi($decimals);
+echo format_pi($pi, $decimals) . "\n";
+?>