The generated PHP

sphp build aims for PHP you would be happy to read and debug. Every file starts with declare(strict_types=1); (unless strictTypes is off), keeps its namespace, uses, doc comments and attributes, and gets PHPDoc that PHPStan understands where native types can't say enough.

StirPHP	PHP
val x = 1, var $x = 1	$x = 1
"${a} and ${b}"	"{$a} and {$b}"
x?->name, x ?: y	$x?->name, $x ?? $y
x!!	$x ?? throw new \TypeError(...)
a == b (StirPHP types)	$a === $b
a / b	$a / $b
a->div(b)	\Stir\Int_div($a, $b)
when (as a value)	match
x is Point	$x instanceof Point, or \is_array(...) checks for records
{ x: Int -> x * 2 }	fn (int $x): int => $x * 2
record Point { ... }	an array; array{x: int, y: int} in PHPDoc
data class	final readonly class with promoted properties
class (not open)	final class
listOf(1, 2), mapOf("a" to 1)	[1, 2], ['a' => 1]
T?, generics, function types	native types plus @param/@return/@template
unknown	mixed
resource	no native type; @param resource in PHPDoc

Extension functions and the runtime

function String.shout() in namespace App becomes the function \App\String_shout($this), and "a"->shout() a call to it. The standard library is emitted the same way into stir-runtime.php in the output directory, in the Stir namespace; generated files that use it require_once it.

With --inline-extensions, calls to expression-bodied extension functions are replaced by their bodies:

val s = "hi"->uppercase()

// without inlining
$s = \Stir\String_uppercase('hi');
// with --inline-extensions
$s = \mb_strtoupper('hi');

Source maps

Next to every .php file, sphp build writes a .php.map (source map v3) pointing back at the .sphp source. Pass --no-source-maps to skip them.