Merge pull request #183 from xp-framework/feature/asymmetric-visibility

Add emitting support for asymmetric visibility

composer.json

@@ -8,7 +8,7 @@
   "require" : {
     "xp-framework/core": "^12.0 | ^11.6 | ^10.16",
     "xp-framework/reflection": "^3.2 | ^2.15",
-    "xp-framework/ast": "^11.1",
+    "xp-framework/ast": "^11.3",
     "php" : ">=7.4.0"
   },
   "require-dev" : {

src/main/php/lang/ast/emit/AsymmetricVisibility.class.php

@@ -0,0 +1,81 @@
+<?php namespace lang\ast\emit;
+
+use lang\ast\nodes\{
+  Assignment,
+  Block,
+  InstanceExpression,
+  Literal,
+  OffsetExpression,
+  ReturnStatement,
+  Variable
+};
+
+/**
+ * Asymmetric Visibility
+ *
+ * @see  https://wiki.php.net/rfc/asymmetric-visibility-v2
+ * @test lang.ast.unittest.emit.AsymmetricVisibilityTest
+ */
+trait AsymmetricVisibility {
+  use VisibilityChecks;
+
+  protected function emitProperty($result, $property) {
+    static $lookup= [
+      'public'         => MODIFIER_PUBLIC,
+      'protected'      => MODIFIER_PROTECTED,
+      'private'        => MODIFIER_PRIVATE,
+      'static'         => MODIFIER_STATIC,
+      'final'          => MODIFIER_FINAL,
+      'abstract'       => MODIFIER_ABSTRACT,
+      'readonly'       => MODIFIER_READONLY,
+      'public(set)'    => 0x1000000,
+      'protected(set)' => 0x0000800,
+      'private(set)'   => 0x0001000,
+    ];
+
+    $scope= $result->codegen->scope[0];
+    $modifiers= 0;
+    foreach ($property->modifiers as $name) {
+      $modifiers|= $lookup[$name];
+    }
+
+    // Declare checks for private(set) and protected(set), folding declarations
+    // like `[visibility] [visibility](set)` to just the visibility itself.
+    if ($modifiers & 0x1000000) {
+      $checks= [];
+      $modifiers&= ~0x1000000;
+    } else if ($modifiers & 0x0000800) {
+      $checks= [$this->protected($property->name, 'modify protected(set)')];
+      $modifiers & MODIFIER_PROTECTED && $modifiers&= ~0x0000800;
+    } else if ($modifiers & 0x0001000) {
+      $checks= [$this->private($property->name, 'modify private(set)')];
+      $modifiers & MODIFIER_PRIVATE && $modifiers&= ~0x0001000;
+    }
+
+    // Emit XP meta information for the reflection API
+    $scope->meta[self::PROPERTY][$property->name]= [
+      DETAIL_RETURNS     => $property->type ? $property->type->name() : 'var',
+      DETAIL_ANNOTATIONS => $property->annotations,
+      DETAIL_COMMENT     => $property->comment,
+      DETAIL_TARGET_ANNO => [],
+      DETAIL_ARGUMENTS   => [$modifiers]
+    ];
+
+    // The readonly flag is really two flags in one: write-once and restricted(set)
+    if (in_array('readonly', $property->modifiers)) {
+      $checks[]= $this->initonce($property->name);
+    }
+
+    $virtual= new InstanceExpression(new Variable('this'), new OffsetExpression(
+      new Literal('__virtual'),
+      new Literal("'{$property->name}'"))
+    );
+    $scope->virtual[$property->name]= [
+      new ReturnStatement($virtual),
+      new Block([...$checks, new Assignment($virtual, '=', new Variable('value'))]),
+    ];
+    if (isset($property->expression)) {
+      $scope->init[sprintf('$this->__virtual["%s"]', $property->name)]= $property->expression;
+    }
+  }
+}

src/main/php/lang/ast/emit/PHP74.class.php

@@ -28,6 +28,8 @@ class PHP74 extends PHP {
     RewriteThrowableExpressions
   ;
 
+  public $targetVersion= 70400;
+
   /** Sets up type => literal mappings */
   public function __construct() {
     $this->literals= [

src/main/php/lang/ast/emit/PHP80.class.php

@@ -31,6 +31,8 @@ class PHP80 extends PHP {
     RewriteStaticVariableInitializations
   ;
 
+  public $targetVersion= 80000;
+
   /** Sets up type => literal mappings */
   public function __construct() {
     $this->literals= [

src/main/php/lang/ast/emit/PHP81.class.php

@@ -23,11 +23,13 @@ class PHP81 extends PHP {
     RewriteBlockLambdaExpressions,
     RewriteDynamicClassConstants,
     RewriteStaticVariableInitializations,
+    RewriteProperties,
     ReadonlyClasses,
-    OmitConstantTypes,
-    PropertyHooks
+    OmitConstantTypes
   ;
 
+  public $targetVersion= 80100;
+
   /** Sets up type => literal mappings */
   public function __construct() {
     $this->literals= [

src/main/php/lang/ast/emit/PHP82.class.php

@@ -23,11 +23,13 @@ class PHP82 extends PHP {
     RewriteBlockLambdaExpressions,
     RewriteDynamicClassConstants,
     RewriteStaticVariableInitializations,
+    RewriteProperties,
     ReadonlyClasses,
-    OmitConstantTypes,
-    PropertyHooks
+    OmitConstantTypes
   ;
 
+  public $targetVersion= 80200;
+
   /** Sets up type => literal mappings */
   public function __construct() {
     $this->literals= [

src/main/php/lang/ast/emit/PHP83.class.php

@@ -18,7 +18,9 @@
  * @see  https://wiki.php.net/rfc#php_83
  */
 class PHP83 extends PHP {
-  use RewriteBlockLambdaExpressions, ReadonlyClasses, PropertyHooks;
+  use RewriteBlockLambdaExpressions, RewriteProperties, ReadonlyClasses;
+
+  public $targetVersion= 80300;
 
   /** Sets up type => literal mappings */
   public function __construct() {

src/main/php/lang/ast/emit/PropertyHooks.class.php

@@ -1,7 +1,6 @@
 <?php namespace lang\ast\emit;
 
 use ReflectionProperty;
-use lang\ast\Code;
 use lang\ast\nodes\{
   Assignment,
   Block,
@@ -24,6 +23,7 @@
  * @test lang.ast.unittest.emit.PropertyHooksTest
  */
 trait PropertyHooks {
+  use VisibilityChecks;
 
   protected function rewriteHook($node, $name, $virtual, $literal) {
 
@@ -61,24 +61,14 @@ protected function rewriteHook($node, $name, $virtual, $literal) {
 
   protected function withScopeCheck($modifiers, $nodes) {
     if ($modifiers & MODIFIER_PRIVATE) {
-      $check= (
-        '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
-        'if (__CLASS__ !== $scope && \\lang\\VirtualProperty::class !== $scope)'.
-        'throw new \\Error("Cannot access private property ".__CLASS__."::".$name);'
-      );
+      return new Block([$this->private('$name', 'access private'), ...$nodes]);
     } else if ($modifiers & MODIFIER_PROTECTED) {
-      $check= (
-        '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
-        'if (__CLASS__ !== $scope && !is_subclass_of($scope, __CLASS__) && \\lang\\VirtualProperty::class !== $scope)'.
-        'throw new \\Error("Cannot access protected property ".__CLASS__."::".$name);'
-      );
+      return new Block([$this->protected('$name', 'access protected'), ...$nodes]);
     } else if (1 === sizeof($nodes)) {
       return $nodes[0];
     } else {
       return new Block($nodes);
     }
-
-    return new Block([new Code($check), ...$nodes]);
   }
 
   protected function emitEmulatedHooks($result, $property) {

src/main/php/lang/ast/emit/ReadonlyProperties.class.php

@@ -1,5 +1,15 @@
 <?php namespace lang\ast\emit;
 
+use lang\ast\nodes\{
+  Assignment,
+  Block,
+  InstanceExpression,
+  InvokeExpression,
+  Literal,
+  OffsetExpression,
+  ReturnStatement,
+  Variable
+};
 use lang\ast\{Code, Error, Errors};
 
 /**
@@ -9,6 +19,7 @@
  * @see  https://wiki.php.net/rfc/readonly_properties_v2
  */
 trait ReadonlyProperties {
+  use VisibilityChecks;
 
   protected function emitProperty($result, $property) {
     static $lookup= [
@@ -37,33 +48,33 @@ protected function emitProperty($result, $property) {
     ];
 
     // Add visibility check for accessing private and protected properties
-    if (in_array('private', $property->modifiers)) {
-      $check= (
-        '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
-        'if (__CLASS__ !== $scope && \\lang\\VirtualProperty::class !== $scope)'.
-        'throw new \\Error("Cannot access private property ".__CLASS__."::\\$%1$s");'
-      );
-    } else if (in_array('protected', $property->modifiers)) {
-      $check= (
-        '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
-        'if (__CLASS__ !== $scope && !is_subclass_of($scope, __CLASS__) && \\lang\\VirtualProperty::class !== $scope)'.
-        'throw new \\Error("Cannot access protected property ".__CLASS__."::\\$%1$s");'
-      );
+    if ($modifiers & MODIFIER_PRIVATE) {
+      $check= $this->private($property->name, 'access private');
+    } else if ($modifiers & MODIFIER_PROTECTED) {
+      $check= $this->protected($property->name, 'access protected');
     } else {
-      $check= '';
+      $check= null;
     }
 
+    $virtual= new InstanceExpression(new Variable('this'), new OffsetExpression(
+      new Literal('__virtual'),
+      new Literal("'{$property->name}'"))
+    );
+
     // Create virtual property implementing the readonly semantics
     $scope->virtual[$property->name]= [
-      new Code(sprintf($check.'return $this->__virtual["%1$s"][0];', $property->name)),
-      new Code(sprintf(
-        ($check ?: '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;').
-        'if (isset($this->__virtual["%1$s"])) throw new \\Error("Cannot modify readonly property ".__CLASS__."::{$name}");'.
-        'if (__CLASS__ !== $scope && \\lang\\VirtualProperty::class !== $scope)'.
-        'throw new \\Error("Cannot initialize readonly property ".__CLASS__."::{$name} from ".($scope ? "scope {$scope}": "global scope"));'.
-        '$this->__virtual["%1$s"]= [$value];',
-        $property->name
-      )),
+      $check ? new Block([$check, new ReturnStatement($virtual)]) : new ReturnStatement($virtual),
+      new Block([
+        $check ?? new Code('$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'),
+        $this->initonce($property->name),
+        new Code(sprintf(
+          'if (__CLASS__ !== $scope && \\lang\\VirtualProperty::class !== $scope)'.
+          'throw new \\Error("Cannot initialize readonly property ".__CLASS__."::{$name} from ".($scope ? "scope {$scope}": "global scope"));'.
+          '$this->__virtual["%1$s"]= [$value];',
+          $property->name
+        )),
+        new Assignment($virtual, '=', new Variable('value'))
+      ]),
     ];
   }
 }

src/main/php/lang/ast/emit/RewriteProperties.class.php

@@ -1,15 +1,26 @@
 <?php namespace lang\ast\emit;
 
+use ReflectionProperty;
+
 trait RewriteProperties {
-  use PropertyHooks, ReadonlyProperties {
+  use PropertyHooks, ReadonlyProperties, AsymmetricVisibility {
     PropertyHooks::emitProperty as emitPropertyHooks;
     ReadonlyProperties::emitProperty as emitReadonlyProperties;
+    AsymmetricVisibility::emitProperty as emitAsymmetricVisibility;
   }
 
   protected function emitProperty($result, $property) {
     if ($property->hooks) {
       return $this->emitPropertyHooks($result, $property);
-    } else if (in_array('readonly', $property->modifiers)) {
+    } else if (
+      $this->targetVersion < 80400 &&
+      array_intersect($property->modifiers, ['private(set)', 'protected(set)', 'public(set)'])
+    ) {
+      return $this->emitAsymmetricVisibility($result, $property);
+    } else if (
+      $this->targetVersion < 80100 &&
+      in_array('readonly', $property->modifiers)
+    ) {
       return $this->emitReadonlyProperties($result, $property);
     }
     parent::emitProperty($result, $property);

src/main/php/lang/ast/emit/VisibilityChecks.class.php

@@ -0,0 +1,26 @@
+<?php namespace lang\ast\emit;
+
+use lang\ast\Code;
+
+trait VisibilityChecks {
+
+  private function initonce($name) {
+    return new Code('if (isset($this->__virtual["'.$name.'"])) throw new \\Error("Cannot modify readonly property ".__CLASS__."::\$'.$name.'");');
+  }
+
+  private function private($name, $access) {
+    return new Code(
+      '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
+      'if (__CLASS__ !== $scope && \\lang\\VirtualProperty::class !== $scope)'.
+      'throw new \\Error("Cannot '.$access.' property ".__CLASS__."::\$'.$name.' from ".($scope ? "scope ".$scope : "global scope"));'
+    );
+  }
+
+  private function protected($name, $access) {
+    return new Code(
+      '$scope= debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]["class"] ?? null;'.
+      'if (__CLASS__ !== $scope && !is_subclass_of($scope, __CLASS__) && \\lang\\VirtualProperty::class !== $scope)'.
+      'throw new \\Error("Cannot '.$access.' property ".__CLASS__."::\$'.$name.' from ".($scope ? "scope ".$scope : "global scope"));'
+    );
+  }
+}