See https://travis-ci.org/xp-framework/compiler/jobs/545844314

Uncaught exception: Exception lang.IllegalArgumentException (
  XP Compiler does not support PHP.8.0.0-dev yet
)

See https://wiki.php.net/rfc/context_sensitive_lexer:

class Collection extends \ArrayAccess, \Countable, \IteratorAggregate {
 
    public function forEach(callable $callback) {
        //...
    }
 
    public function list() {
        //...
    }
 
    public static function new(array $itens) {
        return new self($itens);
    }
}

https://wiki.php.net/rfc/typed_properties_v2 has been implemented. A PHP 7.4 emitter could now emit property types.

For easy access to testing whether a property, constant or method already exists.

Use #[...] instead of << >>, see https://wiki.php.net/rfc/shorter_attribute_syntax

• Support both in the first step in a patch level release
• Add an E_DEPRECATED warning to << >> syntax in order to make unittests fail but production code work in next minor release
• Remove support for << >> in next major release

Emit deprecation warnings for Hack language style arrow functions and compact methods using ==>, instead advocate the use of PHP 7.4 with the fn keyword.

By using warnings, production code will continue to work; while unit tests will fail as seen below:

lang.ast.Emitter::emit() [line 703 of Emitter.class.php] Invalid argument supplied for foreach()

// Works today
$f= ($req, $res) ==> $res->answer(202);

// New
$f= ($req, $res) ==> {
  // ...
  throw new Error(404, 'Not found');
};

Consistent with https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

# Code loaded through standard filesystem classloader
$ xp -w 'return array_pop(get_included_files())'
C:\...\src\main\php\xp\runtime\Modules.class.php

# Code compiled on demand
$ xp -w 'new Test(); return array_pop(get_included_files())'
Test.php

This breaks tools that expect the paths to be absolute.

I've started writing an longer overview including short examples @ https://github.com/xp-framework/compiler/wiki

/cc @mikey179

Only for PHP 5.6, see https://wiki.php.net/rfc/unicode_escape

$str= "\u{1F602}"; // 😂

$name= $user?->name();  // will be null if $user is null

https://docs.hhvm.com/hack/operators/null-safe
https://wiki.php.net/rfc/nullsafe_calls (Draft)

https://wiki.php.net/rfc/named_params - implemented in PHP 8.0:

// Using positional arguments:
array_fill(0, 100, 50);
 
// Using named arguments:
array_fill(start_key: 0, num: 100, val: 50)

• Syntactic support
• Emit argument names in PHP 8
• Argument names erasure for PHP 7 (initial support)
• Check feasibility of full support in PHP 7 (at compile time or at runtime?)

Dynamic traits cannot be resolved, resulting in Cannot instantiate incomplete type com\example\user\lang\partial\Value

In a nutshell

return $user ?? throw new IllegalStateException('No such user');

Would be allowed for the ternary operator, the null-coalesing operator and inside of compact functions.

See also

• https://blogs.msdn.microsoft.com/dotnet/2017/03/09/new-features-in-c-7-0/
• https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/throw
• https://github.com/tc39/proposal-throw-expressions

Inspired by https://www.infoq.com/articles/java-14-feature-spotlight/

records automatically acquire implicit implementations of the canonical constructor (the one whose signature matches the state description), read accessors for each state component (whose names are the same as the component), private final fields for each state component, and state-based implementations of the Object methods equals(), hashCode(), and toString().

Invalid argument supplied for foreach()" in lang\ast\Emitter::emit() (Emitter.class.php, line 774, occured 2 times)

See https://travis-ci.org/xp-framework/compiler/jobs/389491676

Running the test suite with PHP 8.0.0, RC1 yields the following: Compile error (Namespace declaration statement has to be the very first statement or after any declare call in the script)

This is caused by the emitter yielding a ; after the PHP open tag:

$ cat ns.php
<?php ;namespace test;

echo "Works\n";

$ XP_RT=7.4 xp ns.php
Works

$ XP_RT=8.0 xp ns.php
Uncaught error: Compile error (...)

Generate xp::$meta["f.q.c.N"]= ... beneath each type.

This occured when parsing a hack-style lambda:

$authenticate= newinstance(Filter::class, [], [
  'filter' => ($request, $response, $invocation) ==> {
    // ...
  }
]);

I'd expect this to yield a parse error!

https://wiki.php.net/rfc/list_reference_assignment - implemented in PHP 7.3

HHVM 3.24 added a new using statement as a step to deprecate destructors:

interface IDisposable {

  /** Called at the end of a using statement */
  public function __dispose(): void;
}

using ($f= new File()) {
  // ...
}  // $f->__dispose() is implicitly called here

See also https://hhvm.com/blog/2018/01/16/hhvm-3.24.html and https://docs.hhvm.com/hack/disposables/introduction

XP Framework has had a with core function for quite a while, which is similar, but builds ontop of lang.Closeable, see xp-framework/rfc#172. This comes with the overhead of a function call, though. If realized in the compiler, this runtime overhead could be omitted,

$number = 123; 
(int) $number => 123; 
(?int) $number => 123;

$string = '123'; 
(int) $string => 123; 
(?int) $string => 123;

$null = null; 
(int) $null => 0 
(?int) $null => null

See https://externals.io/message/102997

Call to undefined method lang\ast\emit\PHP71::emituse()

https://wiki.php.net/rfc/null_coalesce_equal_operator has been implemented in PHP 7.4

Currently, the compiler supports the Hack language variant, see https://docs.hhvm.com/hack/functions/anonymous-functions:

array_map((User $user) ==> $user->id, $users)

However, PHP 7.4 has decided to go a different way, introducing the fn keyword in https://wiki.php.net/rfc/arrow_functions_v2, which makes it:

array_map(fn(User $user) => $user->id, $users)

The XP Compiler should adopt the latter.

lang.ast.unittest.emit.VarargsTest::list_of

Parameter $args is variadic and has a type constraint (HH\string); variadic params with type constraints are not supported in non-Hack files

In PHP 5, a generator could not return a value: doing so would result in a compile error. An empty return statement was valid syntax within a generator and it would terminate the generator. Since PHP 7.0, a generator can return values, which can be retrieved using Generator::getReturn().

See also http://php.net/manual/en/generator.getreturn.php

Idea:

try {
  …
} catch (LDAPException $e) if (83 === $e->getCode()) {
  …
}

Inspired by C#'s catch … when form:

catch (ArgumentException e) when (e.ParamName == "…")  
{  
}  

(see https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/try-catch)

...and JavaScript's non-standard (and no longer supported) if:

try {
    … 
} catch (e if e instanceof TypeError) {
    // statements to handle TypeError exceptions
}

(see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch)

This breaks the usage for XPCLIs.

Example

" * ONE - the game
 *
 * Get points for posting, commenting and liking on ONE! You become a player
 * in this game by joining https://inside.example.org/one/#walls/453
"

Solution

Replace them as follows inside the Tokens class:

// Old
yield 'comment' => [substr($comment, 2, -3), $line];

// New
yield 'comment' => [trim(preg_replace('/\n\s+\* ?/', "\n", substr($comment, 1, -2))), $line];

...but they're used for example by XP commands:

$ xp cmd Punktestand -?
Uncaught exception: Exception lang.IndexOutOfBoundsException (Undefined offset: 4)
  at <main>::__error(8, (0x13)'Undefined offset: 4', (0x6a)..., 559, array[1]) [line 559 of XPClass.class.php]
  at lang.XPClass::getComment() [line 66 of CmdRunner.class.php]
  at xp.command.CmdRunner::commandUsage(lang.XPClass{}) [line 128 of AbstractRunner.class.php]
# ...

Line 559 reads:

return $details['class'][DETAIL_COMMENT];

Static intializers are not run when loading via CompilingClassLoader.

class Test {
  public function map($function) {
    // ...
  }
}

Causes the error Expected "(", have ")"

lang.ast.syntax.php.ThrowExpression can be integrated as throw expressions are now part of PHP 8, see https://wiki.php.net/rfc/throw_expression

$ XP_RT=8.0 xp -w 'return $args[1] ?? throw new \lang\IllegalArgumentException("Missing arg")'
Uncaught exception: Exception lang.IllegalArgumentException (Missing arg)
  at <main>::include() [line 154 of Code.class.php]
  at xp.runtime.Code::run(array[1]) [line 30 of Dump.class.php]
  at xp.runtime.Dump::main(array[1]) [line 381 of class-main.php]

Add syntactic support for enums

enum WeekDay {
  MON(1), TUE, WED, THU, FRI, SAT, SUN;
}

See:

• https://wiki.php.net/rfc/enum PHP RFC
• xp-framework/rfc#132 XP RFC (merged October 2011)
• https://docs.hhvm.com/hack/enums/introduction Hack Language
• http://captainkuro.com/php/enums-in-php/ Overview of different solutions

If a comment contains a single quote ', a syntax error occurs.

...emitting as var for XP reflection. Only useful for consistency purposes by itself, because you can just as well omit the typehint alltogether from a technical point of view, but important for arrays:

public function headers(): array<string, mixed> {
  // The equivalent of putting `@return [:var]` into the apidocs
}

See https://wiki.php.net/rfc/mixed-typehint and https://docs.hhvm.com/hack/types/type-system#mixed

#[@test]
public function instanceof_imported_type() {
  $r= $this->run('use util\Date; class <T> {
    public function run() {
      return new Date() instanceof Date;
    }
  }');

  $this->assertTrue($r);
}

Assertion fails.

$threshold = 1_000_000_000;  // a billion!
$testValue = ‪107_925_284.88; // scale is hundreds of millions
$discount = 135_00;          // $135, stored as Cents

See https://wiki.php.net/rfc/numeric_literal_separator

Example

// Declaration
class Vector<T> {
  public function add(T $t): self { ... }
  public function get(int $i): T { ... }
}

// Instantiation
$vector= new Vector<string>();

See also

xp-framework/rfc#106
xp-framework/rfc#193
https://wiki.php.net/rfc/generics
https://docs.hhvm.com/hack/generics/introduction

Skipped installation of bin bin/xp.xp-lang.compiler.compile for package xp-framework/compiler: file not found in package

$ xp compile src/main/php dist

The output files' names will be created from the input files' names stripped of the prefix src/main/php and replace the extension with .class.php.

If a class is loaded from a class path during class path setup, and CompilingClassLoader is already registered, it may not find all classes correctly.

FileSystemCL<./vendor/xp-framework/core/src/main/php>
FileSystemCL<./vendor/xp-framework/core/src/main/resources>
FileSystemCL<./vendor/xp-framework/compiler/src/main/php>
CompilingCL<lang.ast.emit.PHP71>
FileSystemCL<./vendor/xp-forge/web/src/main/php>
FileSystemCL<./src/main/php>

If a class is loaded from ./vendor/xp-forge/web/src/main/php during startup, this will initialize the loaders member. Classes requested from ./src/main/php will then no longer be found.

public function __construct(<<inject>> Database $repo) {
  // ...
}

See also xp-framework/rfc#218

....are still parsed from code, rather than being loaded from xp::$meta. Reason ist this is seeded wrongly for namespaces.