git.m6w6.name Git - m6w6/pq-gateway/blob - lib/pq/Query/Expr.php

   1 <?php
   2
   3 namespace pq\Query;
   4
   5 class Expr
   6 {
   7         /**
   8          * @var string
   9          */
  10         protected $expression;
  11
  12         /**
  13          * @var \pq\Query\Expr
  14          */
  15         protected $next;
  16
  17         /**
  18          * @param string $e the expression or a format string followed by arguments
  19          * @param string ...
  20          */
  21         function __construct($e) {
  22                 if (func_num_args() > 1) {
  23                         $e = call_user_func_array("sprintf", func_get_args());
  24                 }
  25                 $this->expression = trim($e);
  26         }
  27
  28         /**
  29          * Get the string expression
  30          * @return string
  31          */
  32         function __toString() {
  33                 return (string) $this->expression . $this->next;
  34         }
  35
  36         /**
  37          * Check for NULL
  38          * @return bool
  39          */
  40         function isNull() {
  41                 return !strcasecmp($this->expression, "null");
  42         }
  43
  44         /**
  45          * Append an expresssion
  46          * @param \pq\Query\Expr $next
  47          * @return \pq\Query\Expr $this
  48          * @throws \UnexpectedValueException if any expr is NULL
  49          */
  50         function add(Expr $next) {
  51                 if ($this->isNull() || $next->isNull()) {
  52                         throw new \UnexpectedValueException("Cannot add anything to NULL");
  53                 }
  54                 for ($that = $this; $that->next; $that = $that->next);
  55                 $that->next = $next;
  56                 return $this;
  57         }
  58 }