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Welcome

Welcome to the documentation of the THP programming languague.

THP is a new programming language that compiles to PHP.

This page discusses some of the design decitions of the language, if you want to install THP go to the installation guide

If you want to learn the language, go to the learn section.

Goals

Bring static typing to PHP: Not just type hints, not just mixed for everything that isn't a primitive type.
Generics & ADTs
Avoid implicit type conversion.
Remove the inconsistencies in the language.
Organize the stdlib into modules.
Differentiate between Arrays, Tuples, Maps and Sets.
Create a consistent language.
Have typings for popular libraries (like TS's .d.ts).
Have a simple instalation and configuration (requiring just Composer).
Ship a fast, native binary (written in Rust) (why use PHP when we can go blazingly fast?).
Support in-place compilation.
(Try to) emit readable PHP.
Implement an LSP server.
Implement a formatter.

Not goals

These are not aspects that THP looks to solve or implement.

Be what TypeScript is for JavaScript (PHP with types).
Use PHP syntax/conventions.
Be familiar for PHP developers.

Philosophy

Consistency over familiarity
Change over conventions
Explicit over implicit

Some differences with PHP

// PHP
$has_key = str_contains($haystack, 'needle');

// THP
val has_key = haystack.contains("needle")

Explicit variable declaration
No $ for variable names (and thus no $$variable)
No semicolons
Use methods on common datatypes
Strings use only double quotes

// PHP
[
    'names' => ['Toni', 'Stark'],
    'age' => 33,
    'numbers' => [32, 64, 128]
]

// THP
.{
    names: #("Toni", "Stark"), // Tuple
    age: 33,
    numbers: [32, 64, 128]
}

Tuples, Arrays, Sets, Maps are clearly different
JSON-like object syntax

// PHP
$cat = new Cat("Michifu", 7);
$cat->meow();

// THP
val cat = Cat("Michifu", 7)
cat.meow();

No new for classes
Use dot . instead of arrow -> syntax

// PHP
use \Some\Deeply\Nested\Class
use \Some\Deeply\Nested\Interface

// THP
use Some::Deeply::Nested::{Class, Interface}

Different module syntax
Explicit module declaration
PSR-4 required
No include, include_once, require or require_once

Other things:

Pattern matching
ADTs

Runtime changes

Where possible THP will compile to available PHP functions/classes/methods/etc.

For example:

// This expression
val greeting = 
    match get_person()
    | Some(person) if person.age > 18
    { 
        "Welcome, {person.name}"
    }
    | Some(person)
    {
        "I'm sorry {person.name}, you need to be 18 or older"
    }
    | None
    {
        "Nobody is here"
    }


// Would compile to:
$greeting = null;
$_person = get_person();
if ($_person !== null) {
    if ($_person["age"] > 18) {
        $greeting = "Welcome, " . $_person["name"];
    }
    else {
        $greeting = "I'm sorry " . $_person["name"] . ", you need to be 18 or older";
    }
}
else {
    $greeting = "Nobody is here";
}

However, more advanced datatypes & helper functions will require a sort of runtime (new classes/functions/etc) or abuse the language's syntax/semantics.

// TBD: Enum compilation
enum IpAddress {
    V4(String),
    V6(String),
}

val ip_1 = IpAddress::V4("255.255.0.0")


// Would possibly compile to:
enum IpAddress {
    V4,
    V6,
}

$ip_1 = [IpAddress::V4, "255.255.0.0"]

Such changes will be documented

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