Search and offset for Posts objects

[michaeltwofish]

The attached patch provides an easy way to find the index of a Post within a Posts object, and find the Post n away from it. This means that you can now get next and previous posts from single post templates relatively easily (some form of which should probably be put into the Theme class or the ThemeHelper plugin).

For example, a horrible and quick implementation might be:

In your theme's theme.php:

public function next( $needle, $params= array() )
{
  return $this->offset($needle, -1, $params);
}

public function previous( $needle, $params= array() )
{
  return $this->offset($needle, 1, $params);
}

private function offset( $needle, $offset, $params= array() )
{
  if ( empty( $params ) ) {
    $params= array( 'content_type' => $needle->content_type, 'status' => 'published', 'nolimit' => 1 );
  }
  $haystack= Posts::get( $params );
  return $haystack->offset($needle, $offset);
}

In your theme's entry.single.php

<?php
  $previous= $theme->previous($post);
  $next= $theme->next($post);
  if ( $previous ) { 
    echo "<a href=\"{$previous->permalink}\" title=\"{$previous->slug}\">{$previous->title}</a>";
  } 
  if ( $previous && $next ) { 
    echo "|";
  } 
  if ( $next ) { 
    echo "<a href=\"{$next->permalink}\" title=\"{$next->slug}\">{$next->title}</a>";
  } 
?>

[michaeltwofish]

There are some flaws in the patch attached. After discussion with ringmaster I have another approach planned.

[michaeltwofish]

Alternate approach committed in r1592. More work is required (allowing arbitrary offsets, more sensible retrieval when not using the default).