Start of factor graph port. Things don't work yet, but a lot of syntax updates towards PHP

PHPSkills/FactorGraphs/Schedule.php

@@ -0,0 +1,89 @@
+<?php
+namespace Moserware\Skills\FactorGraphs;
+
+abstract class Schedule
+{
+    private $_name;
+
+    protected function __construct($name)
+    {
+        $this->_name = $name;
+    }
+
+    public abstract function visit($depth = -1, $maxDepth = 0);
+
+    public function __toString()
+    {
+        return $this->_name;
+    }
+}
+
+class ScheduleStep extends Schedule
+{
+    private $_factor;
+    private $_index;
+
+    public function __construct($name, $factor, $index)
+    {
+        parent::__construct($name);
+        $this->_factor = $factor;
+        $this->_index = $index;
+    }
+
+    public function visit($depth, $maxDepth)
+    {
+        $delta = $this->_factor->updateMessageIndex($this->_index);
+        return $delta;
+    }
+}
+
+class ScheduleSequence extends Schedule
+{
+    private $_schedules;
+
+    public function __construct($name, $schedules)
+    {
+        parent::__construct($name);
+        $this->_schedules = $schedules;
+    }
+
+    public function visit($depth, $maxDepth)
+    {
+        $maxDelta = 0;
+
+        foreach ($this->_schedules as $currentSchedule)
+        {
+            $maxDelta = max($currentSchedule->visit($depth + 1, $maxDepth), $maxDelta);
+        }
+
+        return $maxDelta;
+    }
+}
+
+class ScheduleLoop extends Schedule
+{
+    private $_maxDelta;
+    private $_scheduleToLoop;
+
+    public function __construct($name, Schedule $scheduleToLoop, $maxDelta)
+    {
+        parent::__construct($name);
+        $this->_scheduleToLoop = $scheduleToLoop;
+        $this->_maxDelta = $maxDelta;
+    }
+
+    public function visit($depth, $maxDepth)
+    {
+        $totalIterations = 1;
+        $delta = $this->_scheduleToLoop->visit($depth + 1, $maxDepth);
+        while ($delta > $this->_maxDelta)
+        {
+            $delta = $this->_scheduleToLoop->visit($depth + 1, $maxDepth);
+            $totalIterations++;
+        }
+
+        return $delta;
+    }
+}
+
+?>