Merge pull request #16 from xp-forge/feature/each-with-params

Add support for `each` with block params

src/main/php/com/handlebarsjs/BlockParams.class.php

@@ -0,0 +1,46 @@
+<?php namespace com\handlebarsjs;
+
+use lang\Value;
+use util\Objects;
+
+class BlockParams implements Value {
+  public $names;
+
+  /**
+   * Creates a new constant
+   *
+   * @param  string[] $names
+   */
+  public function __construct($names) {
+    $this->names= $names;
+  }
+
+  /**
+   * (string) cast overloading
+   *
+   * @return string
+   */
+  public function __toString() {
+    return 'as |'.implode(' ', $this->names).'|';
+  }
+
+  /**
+   * Compares
+   *
+   * @param  var $value
+   * @return int
+   */
+  public function compareTo($value) {
+    return $value instanceof self ? Objects::compare($this->names, $value->names) : 1;
+  }
+
+  /** @return string */
+  public function hashCode() {
+    return Objects::hashOf($this->names);
+  }
+
+  /** @return string */
+  public function toString() {
+    return nameof($this).'('.implode(' ', $this->names).')';
+  }
+}

src/main/php/com/handlebarsjs/EachBlockHelper.class.php

@@ -6,6 +6,7 @@
  * @test xp://com.handlebarsjs.unittest.EachHelperTest
  */
 class EachBlockHelper extends BlockNode {
+  private $params;
 
   /**
    * Creates a new with block helper
@@ -18,6 +19,7 @@ class EachBlockHelper extends BlockNode {
    */
   public function __construct($options= [], NodeList $fn= null, NodeList $inverse= null, $start= '{{', $end= '}}') {
     parent::__construct('each', $options, $fn, $inverse, $start, $end);
+    $this->params= isset($options[1]) ? cast($options[1], BlockParams::class)->names : [];
   }
 
   /**
@@ -27,28 +29,14 @@ public function __construct($options= [], NodeList $fn= null, NodeList $inverse=
    * @param  io.streams.OutputStream $out
    */
   public function write($context, $out) {
-    $f= $this->options[0];
-    $target= $f($this, $context, []);
+    $target= $this->options[0]($this, $context, []);
 
     if ($target instanceof \Generator) {
-      $first= true;
-      foreach ($target as $key => $value) {
-        $this->fn->write(new HashContext($key, $first, $context->asContext($value)), $out);
-        $first= false;
-      }
+      (new HashContext($context, $target, ...$this->params))->write($this->fn, $out);
     } else if ($context->isList($target)) {
-      $list= $context->asTraversable($target);
-      $size= sizeof($list);
-      foreach ($list as $index => $element) {
-        $this->fn->write(new ListContext($index, $size, $context->asContext($element)), $out);
-      }
+      (new ListContext($context, $target, ...$this->params))->write($this->fn, $out);
     } else if ($context->isHash($target)) {
-      $hash= $context->asTraversable($target);
-      $first= true;
-      foreach ($hash as $key => $value) {
-        $this->fn->write(new HashContext($key, $first, $context->asContext($value)), $out);
-        $first= false;
-      }
+      (new HashContext($context, $target, ...$this->params))->write($this->fn, $out);
     } else {
       $this->inverse->write($context, $out);
     }

src/main/php/com/handlebarsjs/HandlebarsParser.class.php

@@ -79,10 +79,10 @@ public function options($tag) {
             $value= new Constant(null);
           } else if ('.' === $token) {
             $value= new Lookup(null);
-          } else if ('as' === $token) {                     // Aliases (as |...|)
+          } else if ('as' === $token) {                     // Block parameters (as |...|)
             $o= strpos($tag, '|', $o);
             $p= strcspn($tag, '|', $o + 1);
-            $value= new Alias(trim(substr($tag, $o + 1, $p)));
+            $value= new BlockParams(explode(' ', trim(substr($tag, $o + 1, $p))));
             $p++;
           } else if (strspn($token, '-.0123456789') === strlen($token)) {
             $value= new Constant(strstr($token, '.') ? (double)$token : (int)$token);

src/main/php/com/handlebarsjs/HashContext.class.php

@@ -7,52 +7,63 @@
  *
  * @test  xp://com.handlebarsjs.unittest.EachHelperTest
  */
-class HashContext extends Context {
-  protected $key;
-  protected $first;
-  protected $backing;
+class HashContext extends DataContext {
+  private $map, $element, $index;
+  private $first= true;
+  private $last= null;
+  private $key= null;
 
   /**
    * Constructor
    *
-   * @param  string $key
-   * @param  bool $first
-   * @param  parent $backing
+   * @param  com.github.mustache.Context $parent
+   * @param  [:var]|Generator $iterable
+   * @param  ?string $element
+   * @param  ?string $index
    */
-  public function __construct($key, $first, parent $backing) {
-    parent::__construct($backing->variables, $backing->parent);
-    $this->key= $key;
-    $this->first= $first;
-    $this->backing= $backing;
+  public function __construct(Context $parent, $iterable, $element= null, $index= null) {
+    parent::__construct(null, $parent);
+    $this->map= $iterable;
+    $this->last= is_array($iterable) ? (end($this->map) ? key($this->map) : null) : null; // array_key_last for PHP >= 7.3
+    $this->element= $element;
+    $this->index= $index;
   }
 
   /**
-   * Returns a context inherited from this context
+   * Writes output
    *
-   * @param  var $result
-   * @return self
+   * @param  com.handlebarsjs.Nodes $fn
+   * @param  io.streams.OutputStream $out
    */
-  public function asContext($result) {
-    return new DataContext($result, $this);
+  public function write($fn, $out) {
+
+    // We modify this context directly while we're going - this way,
+    // we save creating context instances for each element.
+    foreach ($this->map as $this->key => $this->variables) {
+      $fn->write($this, $out);
+      $this->first= false;
+    }
   }
 
   /**
-   * Helper method to retrieve a pointer inside a given data structure
-   * using a given segment. Returns null if there is no such segment.
-   * Called from within the `lookup()` method for every segment in the
-   * variable name.
+   * Looks up segments inside a given collection
    *
-   * @param  var $ptr
-   * @param  string $segment
+   * @param  var $v
+   * @param  string[] $segments
    * @return var
    */
-  protected function pointer($ptr, $segment) {
-    if ('@first' === $segment) {
-      return $this->first ? 'true' : null;
-    } else if ('@key' === $segment) {
+  protected function lookup0($v, $segments) {
+    $s= $segments[0];
+    if ('@key' === $s || $this->index === $s) {
       return $this->key;
-    } else {
-      return $this->backing->pointer($ptr, $segment);
+    } else if ('@first' === $s) {
+      return $this->first ? 'true' : null;
+    } else if ('@last' === $s && null !== $this->last) {
+      return $this->key === $this->last ? 'true' : null;
+    } else if ($this->element === $s) {
+      return $this->variables;
     }
+
+    return parent::lookup0($v, $segments);
   }
 }

src/main/php/com/handlebarsjs/ListContext.class.php

@@ -7,54 +7,60 @@
  *
  * @test  xp://com.handlebarsjs.unittest.EachHelperTest
  */
-class ListContext extends Context {
-  protected $index;
-  protected $last;
-  protected $backing;
+class ListContext extends DataContext {
+  private $list, $last, $element, $index;
+  private $offset= null;
 
   /**
    * Constructor
    *
-   * @param  int $index
-   * @param  int $size
-   * @param  parent $backing
+   * @param  com.github.mustache.Context $parent
+   * @param  var[] $list
+   * @param  ?string $element
+   * @param  ?string $index
    */
-  public function __construct($index, $size, parent $backing) {
-    parent::__construct($backing->variables, $backing->parent);
+  public function __construct(Context $parent, $list, $element= null, $index= null) {
+    parent::__construct(null, $parent);
+    $this->list= $list;
+    $this->last= sizeof($this->list) - 1;
+    $this->element= $element;
     $this->index= $index;
-    $this->last= $size - 1;
-    $this->backing= $backing;
   }
 
   /**
-   * Returns a context inherited from this context
+   * Writes output
    *
-   * @param  var $result
-   * @return self
+   * @param  com.handlebarsjs.Nodes $fn
+   * @param  io.streams.OutputStream $out
    */
-  public function asContext($result) {
-    return new DataContext($result, $this);
+  public function write($fn, $out) {
+
+    // We modify this context directly while we're going - this way,
+    // we save creating context instances for each element.
+    foreach ($this->list as $this->offset => $this->variables) {
+      $fn->write($this, $out);
+    }
   }
 
   /**
-   * Helper method to retrieve a pointer inside a given data structure
-   * using a given segment. Returns null if there is no such segment.
-   * Called from within the `lookup()` method for every segment in the
-   * variable name.
+   * Looks up segments inside a given collection
    *
-   * @param  var $ptr
-   * @param  string $segment
+   * @param  var $v
+   * @param  string[] $segments
    * @return var
    */
-  protected function pointer($ptr, $segment) {
-    if ('@first' === $segment) {
-      return 0 === $this->index ? 'true' : null;
-    } else if ('@last' === $segment) {
-      return $this->last === $this->index ? 'true' : null;
-    } else if ('@index' === $segment) {
-      return $this->index;
-    } else {
-      return $this->backing->pointer($ptr, $segment);
+  protected function lookup0($v, $segments) {
+    $s= $segments[0];
+    if ('@index' === $s || $this->index === $s) {
+      return $this->offset;
+    } else if ('@first' === $s) {
+      return 0 === $this->offset ? 'true' : null;
+    } else if ('@last' === $s) {
+      return $this->last === $this->offset ? 'true' : null;
+    } else if ($this->element === $s) {
+      return $this->variables;
     }
+
+    return parent::lookup0($v, $segments);
   }
 }

src/main/php/com/handlebarsjs/WithBlockHelper.class.php

@@ -6,6 +6,7 @@
  * @test xp://com.handlebarsjs.unittest.WithHelperTest
  */
 class WithBlockHelper extends BlockNode {
+  private $alias;
 
   /**
    * Creates a new with block helper
@@ -18,6 +19,7 @@ class WithBlockHelper extends BlockNode {
    */
   public function __construct($options= [], NodeList $fn= null, NodeList $inverse= null, $start= '{{', $end= '}}') {
     parent::__construct('with', $options, $fn, $inverse, $start, $end);
+    $this->alias= isset($options[1]) ? cast($options[1], BlockParams::class)->names[0] : null;
   }
 
   /**
@@ -28,7 +30,7 @@ public function __construct($options= [], NodeList $fn= null, NodeList $inverse=
    */
   public function write($context, $out) {
     $target= $this->options[0]($this, $context, []);
-    $self= $context->asContext(isset($this->options[1]) ? $this->options[1]($this, $target, []) : $target);
+    $self= $context->asContext($this->alias ? [$this->alias => $target] : $target);
 
     if ($context->isTruthy($target)) {
       $this->fn->write($self, $out);