Starting rewriting scope parsing

lib/FauxReadOnly.php

@@ -8,11 +8,13 @@ namespace dW\Lit;
 
 trait FauxReadOnly {
     public function __get(string $name) {
-        if ($name[0] === '_') {
-            return;
+        $prop = "_$name";
+        if (!property_exists($this, $prop)) {
+            $trace = debug_backtrace();
+            trigger_error("Cannot get undefined property $name in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+            return null;
         }
 
-        $prop = "_$name";
-        return $this->$prop;
+        return (!is_array($this->$prop)) ? $this->$prop : clone $this->prop;
     }
 }

lib/Scope/Composite.php

@@ -0,0 +1,28 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Composite extends Node {
+    protected array $expressions = [];
+    protected bool $frozen = false;
+
+
+    public function __construct(Selector $parent) {
+        $this->_parent = \WeakReference::create($parent);
+    }
+
+
+    public function add(Expression ...$expressions): bool {
+        if ($this->frozen) {
+            return false;
+        }
+
+        $this->expressions = $expressions;
+        $this->frozen = true;
+        return true;
+    }
+}

lib/Scope/Data.php

@@ -17,7 +17,7 @@ class Data {
     protected int $endPosition;
 
     public function __construct(string $data) {
-        preg_match_all('/[BLR]:|[A-Za-z0-9-+_\*\.]+|[\,\|\-\(\)&]/', $data, $matches, PREG_OFFSET_CAPTURE);
+        preg_match_all('/[BLR]:|\.|[A-Za-z0-9-+_\*]+|[\,\|\(\)&\^\$\>]/', $data, $matches, PREG_OFFSET_CAPTURE);
         $this->data = $matches[0] ?? [];
         $this->endPosition = count($this->data) - 1;
     }
@@ -37,7 +37,7 @@ class Data {
             return false;
         }
 
-        return $this->data[$this->_position][1];
+        return $this->data[$this->_position + 1][1];
     }
 
     /** Returns the next token without moving the pointer */

lib/Scope/Exception.php

@@ -16,7 +16,7 @@ class Exception extends \Exception {
                 $expected = ($expected[0] !== false) ? $expected[0] : 'end of input';
             } else {
                 $temp = [];
-                for ($i = 0; $i < $strlen; $i++) {
+                for ($i = 0; $i < $expectedLen; $i++) {
                     $temp[] = ($expected[$i] !== false) ? "{$expected[$i]}" : 'end of input';
                 }
                 $expected = $temp;

lib/Scope/Expression.php

@@ -0,0 +1,41 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Expression extends Node {
+    protected Filter|Group|Path $_child;
+    protected bool $frozen = false;
+    protected bool $_negate = false;
+    protected ?string $_operator;
+
+
+    public function __construct(Composite $parent, ?string $operator = null) {
+        $this->_operator = $operator;
+        $this->_parent = \WeakReference::create($parent);
+
+        if ($operator === '-') {
+            $this->negate = true;
+        }
+    }
+
+
+    public function __set(string $name, $value) {
+        if ($name !== 'child') {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set undefined property $name in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+        }
+
+        if ($this->frozen) {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set readonly $name property in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+            return;
+        }
+
+        $this->frozen = true;
+        $this->_child = $value;
+    }
+}

lib/Scope/Filter.php

@@ -0,0 +1,37 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Filter extends Node {
+    protected Group|Path $_child;
+    protected bool $frozen = false;
+    protected string $_operator;
+    protected string $_side;
+
+
+    public function __construct(Selector $parent, string $side) {
+        $this->_parent = \WeakReference::create($parent);
+        $this->_side = $side;
+    }
+
+
+    public function __set(string $name, $value) {
+        if ($name !== 'child') {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set undefined property $name in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+        }
+
+        if ($this->frozen) {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set readonly $name property in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+            return;
+        }
+
+        $this->frozen = true;
+        $this->_child = $value;
+    }
+}

lib/Scope/Group.php

@@ -0,0 +1,34 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Group extends Node {
+    protected Selector $_child;
+    protected bool $frozen = false;
+
+
+    public function __construct(Expression $parent) {
+        $this->_parent = \WeakReference::create($parent);
+    }
+
+
+    public function __set(string $name, $value) {
+        if ($name !== 'child') {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set undefined property $name in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+        }
+
+        if ($this->frozen) {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set readonly $name property in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+            return;
+        }
+
+        $this->frozen = true;
+        $this->_child = $value;
+    }
+}

lib/Scope/Matchers/AndMatcher.php

@@ -1,37 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class AndMatcher extends Matcher {
-    protected array $matchers = [];
-
-    public function __construct(Matcher ...$matchers) {
-        $this->matchers = $matchers;
-    }
-
-    public function add(Matcher $matcher) {
-        $this->matchers[] = $matcher;
-    }
-
-    public function matches(string ...$scopes): bool {
-        foreach ($this->matchers as $m) {
-            if (!$m->matches(...$scopes)) {
-                return false;
-            }
-        }
-
-        return true;
-    }
-
-    public function getPrefix(string ...$scopes): string|null|false {
-        if ($this->matches(...$scopes)) {
-            return $this->matches[0]->getPrefix(...$scopes);
-        }
-
-        return null;
-    }
-}

lib/Scope/Matchers/GroupMatcher.php

@@ -1,27 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class GroupMatcher extends Matcher {
-    protected ?string $prefix;
-    protected Matcher $selector;
-
-    public function __construct(?string $prefix, Matcher $selector) {
-        $this->prefix = ($prefix !== null) ? $prefix[0] : null;
-        $this->selector = $selector;
-    }
-
-    public function matches(string ...$scopes): bool {
-        return $this->selector->matches(...$scopes);
-    }
-
-    public function getPrefix(string ...$scopes): string|null|false {
-        if ($this->selector->matches(...$scopes)) {
-            return $this->prefix;
-        }
-    }
-}

lib/Scope/Matchers/NegateMatcher.php

@@ -1,23 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class NegateMatcher extends Matcher {
-    protected Matcher $matcher;
-
-    public function __construct(Matcher $matcher) {
-        $this->matcher = $matcher;
-    }
-
-    public function matches(string ...$scopes): bool {
-        return !($this->matcher->matches(...$scopes));
-    }
-
-    public function getPrefix(string ...$scopes) {
-        return null;
-    }
-}

lib/Scope/Matchers/OrMatcher.php

@@ -1,40 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class OrMatcher extends Matcher {
-    protected array $matchers = [];
-
-    public function __construct(Matcher ...$matchers) {
-        $this->matchers = $matchers;
-    }
-
-    public function add(Matcher $matcher) {
-        $this->matchers[] = $matcher;
-    }
-
-    public function matches(string ...$scopes): bool {
-        foreach ($this->matchers as $m) {
-            if ($m->matches(...$scopes)) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    public function getPrefix(string ...$scopes): string|null|false {
-        foreach ($this->matchers as $m) {
-            $prefix = $m->getPrefix(...$scopes);
-            if ($prefix !== null) {
-                return $prefix;
-            }
-        }
-
-        return null;
-    }
-}

lib/Scope/Matchers/PathMatcher.php

@@ -1,37 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class PathMatcher extends Matcher {
-    protected ?string $prefix;
-    protected array $matchers;
-
-    public function __construct(?string $prefix, ScopeMatcher ...$matchers) {
-        $this->prefix = ($prefix !== null) ? $prefix[0] : null;
-        $this->matchers = $matchers;
-    }
-
-    public function matches(string ...$scopes): bool {
-        $count = 0;
-        $matcher = $this->matchers[$count];
-        foreach ($scopes as $scope) {
-            if ($matcher->matches($scope)) {
-                 $matcher = $this->matchers[++$count] ?? null;
-            }
-            if ($matcher === null) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    public function getPrefix(string ...$scopes): string|null|false {
-        if ($this->matches($scopes)) {
-            return $this->prefix;
-        }
-    }
-}

lib/Scope/Matchers/ScopeMatcher.php

@@ -1,39 +0,0 @@
-<?php
-/** @license MIT
- * Copyright 2021 Dustin Wilson et al.
- * See LICENSE file for details */
-
-declare(strict_types=1);
-namespace dW\Lit\Scope;
-
-class ScopeMatcher extends Matcher {
-    protected array $segments;
-
-    public function __construct(string ...$segments) {
-        $this->segments = $segments;
-    }
-
-    public function matches(string $scope): bool {
-        $scopeSegments = explode('.', $scope);
-
-        if (count($this->segments) !== count($scopeSegments)) {
-            return false;
-        }
-
-        foreach ($this->segments as $index => $segment) {
-            if ($segment === '*') {
-                continue;
-            }
-
-            if ($segment !== $scopeSegments[$index]) {
-                return false;
-            }
-        }
-
-        return true;
-    }
-
-    public function getPrefix(string $scope) {
-        return null;
-    }
-}

lib/Scope/Matcher.php → lib/Scope/Node.php

@@ -5,5 +5,10 @@
 
 declare(strict_types=1);
 namespace dW\Lit\Scope;
+use dW\Lit\FauxReadOnly;
 
-abstract class Matcher {}
+class Node {
+    use FauxReadOnly;
+
+    protected ?\WeakReference $_parent;
+}

lib/Scope/Parser.php

@@ -6,9 +6,9 @@
 declare(strict_types=1);
 namespace dW\Lit\Scope;
 
-/** Parses scope strings into a matcher tree */
+/** Parses strings into a scope selector */
 class Parser {
-    // Used to cache parsed scopes
+    // Used to cache parsed selectors
     protected static array $cache = [];
 
     // When true prints out detailed data about the construction of the matcher
@@ -25,56 +25,40 @@ class Parser {
     protected static Parser $instance;
 
     // strspn mask used to check whether a token could be a valid scope.
-    protected const SCOPE_MASK = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-+_.*';
+    protected const SCOPE_MASK = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-+_*';
 
 
     protected function __construct(string $selector) {
         $this->data = new Data($selector);
     }
 
-    /**
-     * Static method entry point for the class. Creates the instance and parses the
-     * string.
-     */
-    public static function parse(string $selector): Matcher|false {
-        if (isset(self::$cache[$selector])) {
-            return self::$cache[$selector];
+    /** Static method entry point for the class. Parses the string. */
+    public static function parse(string $string): Selector {
+        if (isset(self::$cache[$string])) {
+            return self::$cache[$string];
         }
 
-        self::$instance = new self($selector);
+        self::$instance = new self($string);
         $result = self::parseSelector();
-        self::$cache[$selector] = $result;
+        self::$cache[$string] = $result;
         return $result;
     }
 
 
-    protected static function parseComposite(): Matcher {
+    protected static function parseComposite(?Selector $parent = null): Matcher {
         if (self::$debug) {
             self::debug();
         }
 
-        $result = self::parseExpression();
+        $result = new Composite($parent);
+        $expressions = [ self::parseExpression($result) ];
 
-        $peek = self::$instance->data->peek();
-        while (in_array($peek, [ '|', '&', '-' ])) {
-            $token = self::$instance->data->consume();
-            $new = self::parseExpression();
-
-            switch ($token) {
-                case '|':
-                    $result = ($result instanceof OrMatcher) ? $result->add($new) : new OrMatcher($result, $new);
-                break;
-
-                case '-':
-                    $new = new NegateMatcher($new);
-                case '&':
-                    $result = ($result instanceof AndMatcher) ? $result->add($new) : new AndMatcher($result, $new);
-                break;
-            }
-
-            $peek = self::$instance->data->peek();
+        while ($peek = self::$instance->data->peek() && in_array($peek, [ '&', '|', '-' ])) {
+            $expressions[] = self::parseExpression($result, self::$instance->data->consume());
         }
 
+        $result->add(...$expressions);
+
         if (self::$debug) {
             self::debugResult($result);
         }
@@ -82,27 +66,40 @@ class Parser {
         return $result;
     }
 
-    protected static function parseExpression(): Matcher {
+    protected static function parseExpression(Composite $parent, ?string $operator = null): Expression {
         if (self::$debug) {
             self::debug();
         }
 
+        $result = new Expression($parent, $operator);
+
         $peek = self::$instance->data->peek();
-        $prefix = null;
-        if ($peek !== false && in_array($peek[0], [ 'B', 'L', 'R' ]) && $peek[1] === ':') {
-            $prefix = $peek[0];
-            self::$instance->data->consume();
-            $peek = self::$instance->data->peek();
+        if (in_array($peek[0], [ 'B', 'L', 'R' ])) {
+            $result->child = self::parseFilter($result, self::$instance->data->consume()[0]);
+        } elseif ($peek === '(') {
+            $result->child = self::parseGroup($result);
+        } else {
+            $result->child = self::parsePath($result);
         }
 
+        if (self::$debug) {
+            self::debugResult($result);
+        }
+
+        return $result;
+    }
+
+    protected static function parseFilter(Expression $parent, string $side): Filter {
+        if (self::$debug) {
+            self::debug();
+        }
+
+        $result = new Filter($parent, $side);
+        $peek = self::$instance->data->peek();
         if ($peek === '(') {
-            self::$instance->data->consume();
-            $result = self::parseGroup($prefix);
-        } elseif (!in_array($peek, [ '-', false ]) && strspn($peek, self::SCOPE_MASK) === strlen($peek)) {
-            $result = self::parsePath($prefix);
+            $result->child = self::parseGroup($result);
         } else {
-            // TODO: Take the effort to make this more descriptive
-            self::throw([ 'Group', 'Path', 'Scope' ], $peek);
+            $result->child = self::parsePath($result);
         }
 
         if (self::$debug) {
@@ -112,19 +109,27 @@ class Parser {
         return $result;
     }
 
-    protected static function parseGroup(?string $prefix = null): Matcher {
+    protected static function parseGroup(Expression $parent): Group {
         if (self::$debug) {
             self::debug();
         }
 
-        $result = self::parseSelector();
+        $result = new Group($parent);
+
+        $token = self::$instance->data->consume();
+        if ($token !== '(') {
+            self::throw('"("', $token);
+        }
+
+        if (!$group->child = self::parseSelector($result)) {
+            return false;
+        }
+
         $token = self::$instance->data->consume();
         if ($token !== ')') {
             self::throw('")"', $token);
         }
 
-        $result = ($prefix === null) ? $result : new GroupMatcher($prefix, $result);
-
         if (self::$debug) {
             self::debugResult($result);
         }
@@ -132,21 +137,44 @@ class Parser {
         return $result;
     }
 
-    protected static function parsePath(?string $prefix = null): PathMatcher|ScopeMatcher {
+    protected static function parsePath(Expression $parent): Path {
         if (self::$debug) {
             self::debug();
         }
 
-        $result = [];
-        $result[] = self::parseScope();
+        $result = new Path($parent);
 
-        $peek = self::$instance->data->peek();
-        while (!in_array($peek, [ '-', false ]) && strspn($peek, self::SCOPE_MASK) === strlen($peek)) {
-            $result[] = self::parseScope();
-            $peek = self::$instance->data->peek();
+        $anchorStart = false;
+        if (self::$instance->data->peek() === '^') {
+            $anchorStart = true;
+            self::$instance->data->consume();
+        }
+
+        $first = self::parseScope($result);
+        if ($first->anchorToPrevious) {
+            self::throw('first scope', '>');
+        }
+
+        $scopes = [ $first ];
+        while ($peek = self::$instance->data->peek() && strspn($peek, self::SCOPE_MASK) === strlen($peek)) {
+            $scopes[] = self::parseScope($result);
         }
 
-        $result = ($prefix !== null || count($result) > 1) ? new PathMatcher($prefix, ...$result) : $result[0];
+        $result->add(...$scopes);
+
+        $anchorEnd = false;
+        if (self::$instance->data->peek() === '$') {
+            $anchorEnd = true;
+            self::$instance->data->consume();
+        }
+
+        if ($anchorStart && $anchorEnd) {
+            $result->anchor = Path::ANCHOR_BOTH;
+        } elseif ($anchorStart) {
+            $result->anchor = Path::ANCHOR_START;
+        } else {
+            $result->anchor = Path::ANCHOR_END;
+        }
 
         if (self::$debug) {
             self::debugResult($result);
@@ -155,22 +183,20 @@ class Parser {
         return $result;
     }
 
-    protected static function parseSelector(): Matcher {
+    protected static function parseSelector(?Group $parent = null): Matcher {
         if (self::$debug) {
             self::debug();
         }
 
-        $result = [];
-        $result[] = self::parseComposite();
+        $result = new Selector($parent);
 
-        $peek = self::$instance->data->peek();
-        while ($peek === ',') {
+        $composites = [ self::parseComposite($result) ];
+        while ($peek = self::$instance->data->peek() && $peek === ',') {
             self::$instance->data->consume();
-            $result[] = self::parseComposite();
-            $peek = self::$instance->data->peek();
+            $composites[] = self::parseComposite($result);
         }
 
-        $result = (count($result) > 1) ? new OrMatcher(...$result) : $result[0];
+        $result->add(...$composites);
 
         if (self::$debug) {
             self::debugResult($result);
@@ -179,18 +205,35 @@ class Parser {
         return $result;
     }
 
-    protected static function parseScope(): ScopeMatcher {
+    protected static function parseScope(Path $parent): Scope {
         if (self::$debug) {
             self::debug();
         }
 
-        $token = self::$instance->data->consume();
-        if ($token === false || !preg_match('/^(?:[A-Za-z0-9-_]+|\*)(?:\.(?:[A-Za-z0-9-+_]+|\*))*$/S', $token)) {
-            // TODO: Take the effort to make this more descriptive
-            self::throw('valid scope syntax', $token);
+        $peek = self::$instance->data->peek();
+        if ($peek === '>') {
+            self::$instance->data->consume();
         }
 
-        $result = new ScopeMatcher(...explode('.', $token));
+        $result = new Scope($parent, ($peek === '>'));
+        $atoms = [];
+        $first = true;
+        do {
+            if (!$first) {
+                // Consume the period
+                self::$instance->data->consume();
+            }
+
+            $peek = self::$instance->data->peek();
+            if (strspn($peek, self::SCOPE_MASK) !== strlen($peek)) {
+                self::throw([ 'A-Z', 'a-z', '0-9', '-', '+', '_', '*' ], $peek);
+            }
+
+            $atoms[] = self::$instance->data->consume();
+            $first = false;
+        } while (self::$instance->data->peek() === '.');
+
+        $result->add(...$atoms);
 
         if (self::$debug) {
             self::debugResult($result);

lib/Scope/Path.php

@@ -0,0 +1,56 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Path extends Node {
+    protected int $_anchor;
+
+    protected array $frozen = [
+        'add' => false,
+        'anchor' => false
+    ];
+
+    protected array $scopes = [];
+
+    const ANCHOR_NONE = 0;
+    const ANCHOR_START = 1;
+    const ANCHOR_END = 2;
+    const ANCHOR_BOTH = 3;
+
+
+    public function __construct(Expression $parent) {
+        $this->_parent = \WeakReference::create($parent);
+    }
+
+
+    public function add(Scope ...$scopes): bool {
+        if ($this->frozen['add']) {
+            return false;
+        }
+
+        $this->scopes = $scopes;
+        $this->frozen['add'] = true;
+        return true;
+    }
+
+
+    public function __set(string $name, $value) {
+        if ($name !== 'anchor') {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set undefined property $name in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+        }
+
+        if ($this->frozen['anchor']) {
+            $trace = debug_backtrace();
+            trigger_error("Cannot set readonly $name property in {$trace[0]['file']} on line {$trace[0]['line']}", E_USER_NOTICE);
+            return;
+        }
+
+        $this->frozen['anchor'] = true;
+        $this->_anchor = $value;
+    }
+}

lib/Scope/Scope.php

@@ -0,0 +1,30 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Scope extends Node {
+    protected bool $_anchorToPrevious;
+    protected array $atoms = [];
+    protected bool $frozen = false;
+
+
+    public function __construct(Path $parent, bool $anchorToPrevious = false) {
+        $this->_anchorToPrevious = $anchorToPrevious;
+        $this->_parent = \WeakReference::create($parent);
+    }
+
+
+    public function add(string ...$atoms): bool {
+        if ($this->frozen) {
+            return false;
+        }
+
+        $this->atoms = $atoms;
+        $this->frozen = true;
+        return true;
+    }
+}

lib/Scope/Selector.php

@@ -0,0 +1,28 @@
+<?php
+/** @license MIT
+ * Copyright 2021 Dustin Wilson et al.
+ * See LICENSE file for details */
+
+declare(strict_types=1);
+namespace dW\Lit\Scope;
+
+class Selector extends Node {
+    protected array $composites = [];
+    protected bool $frozen = false;
+
+
+    public function __construct(?Group $parent = null) {
+        $this->_parent = ($parent === null) ? null : \WeakReference::create($parent);
+    }
+
+
+    public function add(Composite ...$composites): bool {
+        if ($this->frozen) {
+            return false;
+        }
+
+        $this->composites = $this->composites;
+        $this->frozen = true;
+        return true;
+    }
+}