Add map and iter to doc list

src/DocumentList.php

@@ -24,6 +24,9 @@ class DocumentList
     /** @var TDoc|null $first The first item from the results  */
     private mixed $first = null;
 
+    /** @var bool $isConsumed This is set to true once the generator has been exhausted */
+    private bool $isConsumed = false;
+
     /**
      * Constructor
      *
@@ -39,6 +42,75 @@ class DocumentList
         }
     }
 
+    /**
+     * Does this list have items remaining?
+     *
+     * @return bool True if there are items still to be retrieved from the list, false if not
+     */
+    public function hasItems(): bool
+    {
+        return !is_null($this->result);
+    }
+
+    /**
+     * The items from the query result
+     *
+     * @return Generator<TDoc> The items from the document list
+     * @throws DocumentException If this is called once the generator has been consumed
+     */
+    public function items(): Generator
+    {
+        if (!$this->result) {
+            if ($this->isConsumed) {
+                throw new DocumentException('Cannot call items() multiple times');
+            }
+            $this->isConsumed = true;
+            return;
+        }
+        yield $this->first;
+        while ($row = $this->result->fetch(PDO::FETCH_ASSOC)) {
+            yield $this->mapper->map($row);
+        }
+        $this->isConsumed = true;
+        $this->result     = null;
+    }
+
+    /**
+     * Map items by consuming the generator
+     *
+     * @template U The type to which each item should be mapped
+     * @param callable(TDoc): U $map The mapping function
+     * @return Generator<U> The result of the mapping function
+     * @throws DocumentException If this is called once the generator has been consumed
+     */
+    public function map(callable $map): Generator
+    {
+        foreach ($this->items() as $item) {
+            yield $map($item);
+        }
+    }
+
+    /**
+     * Iterate the generator, running the given function for each item
+     *
+     * @param callable(TDoc): void $f The function to run for each item
+     * @throws DocumentException If this is called once the generator has been consumed
+     */
+    public function iter(callable $f): void
+    {
+        foreach ($this->items() as $item) {
+            $f($item);
+        }
+    }
+
+    /**
+     * Ensure the statement is destroyed if the generator is not exhausted
+     */
+    public function __destruct()
+    {
+        if (!is_null($this->result)) $this->result = null;
+    }
+
     /**
      * Construct a new document list
      *
@@ -53,37 +125,4 @@ class DocumentList
         $stmt = &Custom::runQuery($query, $parameters);
         return new static($stmt, $mapper);
     }
-
-    /**
-     * The items from the query result
-     *
-     * @return Generator<TDoc> The items from the document list
-     */
-    public function items(): Generator
-    {
-        if (!$this->result) return;
-        yield $this->first;
-        while ($row = $this->result->fetch(PDO::FETCH_ASSOC)) {
-            yield $this->mapper->map($row);
-        }
-        $this->result = null;
-    }
-
-    /**
-     * Does this list have items remaining?
-     *
-     * @return bool True if there are items still to be retrieved from the list, false if not
-     */
-    public function hasItems(): bool
-    {
-        return !is_null($this->result);
-    }
-
-    /**
-     * Ensure the statement is destroyed if the generator is not exhausted
-     */
-    public function __destruct()
-    {
-        if (!is_null($this->result)) $this->result = null;
-    }
 }

src/Parameters.php

@@ -95,7 +95,8 @@ class Parameters
         $mode = Configuration::mode('generate field name parameters');
         return match ($mode) {
             Mode::PgSQL  => [$paramName => "{" . implode(",", $fieldNames) . "}"],
-            Mode::SQLite => array_combine(array_map(fn($idx) => $paramName . $idx, range(0, sizeof($fieldNames) - 1)),
+            Mode::SQLite => array_combine(array_map(fn($idx) => $paramName . $idx,
+                                              empty($fieldNames) ? [] : range(0, sizeof($fieldNames) - 1)),
                                           array_map(fn($field) => "$.$field", $fieldNames))
         };
     }