From 3a7d3a198d6f6e7f46bcf48dfe071a8a6999b341 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wenzel=20P=C3=BCnter?= <wenzel@phelix.me>
Date: Thu, 23 Oct 2014 16:57:08 +0200
Subject: [PATCH] Prefer single quotes

---
 src/Isbn/CheckDigit.php |  2 +-
 src/Isbn/Hyphens.php    | 10 +++++-----
 src/Isbn/Translate.php  |  4 ++--
 src/Isbn/Validation.php |  6 +++---
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/Isbn/CheckDigit.php b/src/Isbn/CheckDigit.php
index 96bd338..1f34b8d 100644
--- a/src/Isbn/CheckDigit.php
+++ b/src/Isbn/CheckDigit.php
@@ -75,7 +75,7 @@ public function make10($isbn)
         //Calculate check digit
         $check = 0;
         for ($i = 0; $i < 9; $i++) {
-            if ($isbn[$i] === "X") {
+            if ($isbn[$i] === 'X') {
                 $check += 10 * intval(10 - $i);
             } else {
                 $check += intval($isbn[$i]) * intval(10 - $i);
diff --git a/src/Isbn/Hyphens.php b/src/Isbn/Hyphens.php
index 3692176..3022cd0 100644
--- a/src/Isbn/Hyphens.php
+++ b/src/Isbn/Hyphens.php
@@ -42,8 +42,8 @@ public function removeHyphens($isbn)
             throw new Exception('Invalid parameter type.');
         }
 
-        $isbn = str_replace(" ", "", $isbn);
-        $isbn = str_replace("-", "", $isbn);
+        $isbn = str_replace(' ', '', $isbn);
+        $isbn = str_replace('-', '', $isbn);
         return $isbn;
     }
 
@@ -54,7 +54,7 @@ public function removeHyphens($isbn)
      * @param string $char
      * @return string
     */
-    public function fixHyphens($isbn, $char = "-")
+    public function fixHyphens($isbn, $char = '-')
     {
         $isbn = $this->removeHyphens($isbn);
         return $this->addHyphens($isbn, $char);
@@ -67,7 +67,7 @@ public function fixHyphens($isbn, $char = "-")
      * @param string $char
      * @throws Exception
     */
-    public function addHyphens($isbn, $char = "-")
+    public function addHyphens($isbn, $char = '-')
     {
         if(is_string($isbn) === false ||
             is_string($char) === false) {
@@ -168,7 +168,7 @@ private function getRegistrantElement()
         if (isset($this->isbnSplit[0]) === true) {
             $soFar = implode('-', $this->isbnSplit);
         } else {
-            $soFar = "978-".$this->isbnSplit[1];
+            $soFar = '978-'.$this->isbnSplit[1];
         }
 
         switch ($soFar) {
diff --git a/src/Isbn/Translate.php b/src/Isbn/Translate.php
index 05ae58c..782c515 100644
--- a/src/Isbn/Translate.php
+++ b/src/Isbn/Translate.php
@@ -71,9 +71,9 @@ public function to13($isbn)
         $isbn = substr($isbn, 0, -1);
 
         if (strlen($isbn) > 9) {
-            $isbn = "978-".$isbn;
+            $isbn = '978-'.$isbn;
         } else {
-            $isbn = "978".$isbn;
+            $isbn = '978'.$isbn;
         }
 
         return $isbn.$this->checkDigit->make($isbn);
diff --git a/src/Isbn/Validation.php b/src/Isbn/Validation.php
index f2b5070..d367ad6 100644
--- a/src/Isbn/Validation.php
+++ b/src/Isbn/Validation.php
@@ -74,14 +74,14 @@ public function isbn10($isbn)
         if (strlen($isbn) != 10) {
             return false;
         }
-        if (preg_match("/\d{9}[0-9xX]/i",$isbn) == false) {
+        if (preg_match('/\d{9}[0-9xX]/i',$isbn) == false) {
             return false;
         }
 
         //Verify checksum
         $check = 0;
         for ($i = 0; $i < 10; $i++) {
-            if ($isbn[$i] === "X") {
+            if ($isbn[$i] === 'X') {
                 $check += 10 * intval(10 - $i);
             } else {
                 $check += intval($isbn[$i]) * intval(10 - $i);
@@ -108,7 +108,7 @@ public function isbn13($isbn)
         if (strlen($isbn) != 13) {
             return false;
         }
-        if (preg_match("/\d{13}/i",$isbn) == false) {
+        if (preg_match('/\d{13}/i',$isbn) == false) {
             return false;
         }