Added check spaces around dot when concatenating strings for #24 (#26)

Author: edgardmessias

Yii2/Sniffs/Files/SpacesAroundConcatSniff.php

@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * Class for a sniff to oblige whitespaces before and after a concatenation operator
+ *
+ * This Sniff check if a whitespace is missing before or after any concatenation
+ * operator.
+ * The concatenation operator is identified by the PHP token T_STRING_CONCAT
+ * The whitespace is identified by the PHP token T_WHITESPACE
+ *
+ * @since 2.0.2
+ */
+class Yii2_Sniffs_Files_SpacesAroundConcatSniff implements PHP_CodeSniffer_Sniff
+{
+    public function register()
+    {
+        return [T_STRING_CONCAT];
+    }
+
+    public function process(PHP_CodeSniffer_File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        if ($tokens[$stackPtr-1]['type'] !== 'T_WHITESPACE') {
+            $error = 'Whitespace is expected before any concat operator "."';
+            $fix = $phpcsFile->addFixableError($error, $stackPtr, 'NoSpace');
+            if ($fix === true) {
+                $phpcsFile->fixer->addContentBefore($stackPtr, ' ');
+            }
+        }
+        if ($tokens[$stackPtr+1]['type'] !== 'T_WHITESPACE') {
+            $error = 'Whitespace is expected after any concat operator "."';
+            $fix = $phpcsFile->addFixableError($error, $stackPtr, 'NoSpace');
+            if ($fix === true) {
+                $phpcsFile->fixer->addContent($stackPtr, ' ');
+            }
+        }
+    }
+}