Moves MPT static methods to a separate helper class (Path)

readme.md

@@ -109,8 +109,10 @@ The following tree will be used in the examples below:
 ```
 
 Simple example of a fixed-length MPT:
+
 ```php
 use Any\Item;
+use Dakujem\Oliva\MaterializedPath\Path;
 use Dakujem\Oliva\MaterializedPath\TreeBuilder;
 use Dakujem\Oliva\Node;
 
@@ -128,7 +130,7 @@ $collection = [
 
 $builder = new TreeBuilder(
     node: fn(Item $item) => new Node($item),      // How to create a node.
-    vector: TreeBuilder::fixed(                   // How to extract path vector.
+    vector: Path::fixed(                          // How to extract path vector.
         levelWidth: 3,
         accessor: fn(Item $item) => $item->path,
     ),
@@ -140,8 +142,10 @@ $root = $builder->build(
 ```
 
 Same example with an equivalent delimited MPT:
+
 ```php
 use Any\Item;
+use Dakujem\Oliva\MaterializedPath\Path;
 use Dakujem\Oliva\MaterializedPath\TreeBuilder;
 use Dakujem\Oliva\Node;
 
@@ -158,7 +162,7 @@ $collection = [
 
 $builder = new TreeBuilder(
     node: fn(Item $item) => new Node($item),      // How to create a node.
-    vector: TreeBuilder::delimited(               // How to extract path vector.
+    vector: Path::delimited(                      // How to extract path vector.
         delimiter: '.',
         accessor: fn(Item $item) => $item->path,
     ),

src/MaterializedPath/Path.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dakujem\Oliva\MaterializedPath;
+
+use LogicException;
+
+/**
+ * @author Andrej Rypak <xrypak@gmail.com>
+ */
+final class Path
+{
+    /**
+     * Creates an extractor callable for tree builders that extracts vectors from materialized paths with delimiters.
+     * These paths contain hierarchy information with variable-width levels delimited by a selected character.
+     * The vectors are extracted by exploding the path string.
+     *
+     * @param string $delimiter The delimiter character.
+     * @param callable $accessor An accessor callable that returns the raw path, signature `fn(mixed $data, mixed $inputIndex, TreeNodeContract $node): string`.
+     * @return callable Vector extractor for the MPT builder.
+     */
+    public static function delimited(string $delimiter, callable $accessor): callable
+    {
+        if (strlen($delimiter) !== 1) {
+            throw new LogicException('The delimiter must be a single character.');
+        }
+        return function (mixed $data) use ($delimiter, $accessor): array {
+            $path = $accessor($data);
+            if (null === $path) {
+                return [];
+            }
+            if (!is_string($path)) {
+                // TODO improve exceptions (index/path etc)
+                throw new InvalidTreePath('Invalid tree path returned by the accessor. A string is required.');
+            }
+            $path = trim($path, $delimiter);
+            if ('' === $path) {
+                return [];
+            }
+            return explode($delimiter, $path);
+        };
+    }
+
+    /**
+     * Creates an extractor callable for tree builders that extracts vectors from materialized paths without delimiters.
+     * These paths contain hierarchy information with constant character count per level of depth.
+     * The vectors are extracted by splitting the path string by the given number.
+     *
+     * @param int $levelWidth The number of characters per level.
+     * @param callable $accessor An accessor callable that returns the raw path, signature `fn(mixed $data, mixed $inputIndex, TreeNodeContract $node): string`.
+     * @return callable Vector extractor for the MPT builder.
+     */
+    public static function fixed(int $levelWidth, callable $accessor): callable
+    {
+        return function (mixed $data) use ($levelWidth, $accessor): array {
+            $path = $accessor($data);
+            if (null === $path || $path === '') {
+                return [];
+            }
+            if (!is_string($path)) {
+                // TODO improve exceptions (index/path etc)
+                throw new InvalidTreePath('Invalid tree path returned by the accessor. A string is required.');
+            }
+            return str_split($path, $levelWidth);
+        };
+    }
+}

src/MaterializedPath/TreeBuilder.php

@@ -67,43 +67,6 @@ public function __construct(
         $this->vector = $vector;
     }
 
-    public static function fixed(int $levelWidth, callable $accessor): callable
-    {
-        return function (mixed $data) use ($levelWidth, $accessor): array {
-            $path = $accessor($data);
-            if (null === $path || $path === '') {
-                return [];
-            }
-            if (!is_string($path)) {
-                // TODO improve exceptions (index/path etc)
-                throw new InvalidTreePath('Invalid tree path returned by the accessor. A string is required.');
-            }
-            return str_split($path, $levelWidth);
-        };
-    }
-
-    public static function delimited(string $delimiter, callable $accessor): callable
-    {
-        if (strlen($delimiter) !== 1) {
-            throw new LogicException('The delimiter must be a single character.');
-        }
-        return function (mixed $data) use ($delimiter, $accessor): array {
-            $path = $accessor($data);
-            if (null === $path) {
-                return [];
-            }
-            if (!is_string($path)) {
-                // TODO improve exceptions (index/path etc)
-                throw new InvalidTreePath('Invalid tree path returned by the accessor. A string is required.');
-            }
-            $path = trim($path, $delimiter);
-            if ('' === $path) {
-                return [];
-            }
-            return explode($delimiter, $path);
-        };
-    }
-
     public function build(iterable $input): TreeNodeContract
     {
         $root = $this->processInput($input)->root();

tests/mptree.phpt

@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Dakujem\Oliva\Iterator\PreOrderTraversal;
+use Dakujem\Oliva\MaterializedPath\Path;
 use Dakujem\Oliva\MaterializedPath\Support\AlmostThere;
 use Dakujem\Oliva\MaterializedPath\TreeBuilder;
 use Dakujem\Oliva\Node;
@@ -53,7 +54,7 @@ class Item
 
     $builder = new TreeBuilder(
         node: fn(?Item $item) => new Node($item),
-        vector: TreeBuilder::fixed(
+        vector: Path::fixed(
             3,
             fn(?Item $item) => $item?->path,
         ),
@@ -80,7 +81,7 @@ class Item
     ], $toArray($almost->root()));
 
 
-    $vectorExtractor = TreeBuilder::fixed(
+    $vectorExtractor = Path::fixed(
         3,
         fn(mixed $path) => $path,
     );
@@ -139,7 +140,7 @@ class Item
 
     $builder = new TreeBuilder(
         node: fn(Item $item) => new Node($item),
-        vector: TreeBuilder::delimited(
+        vector: Path::delimited(
             delimiter: '.',
             accessor: fn(Item $item) => $item->path,
         ),