Merge pull request #1788 from udan11/lint

[WIP] Added lint.

30 files changed, 973 insertions, 191 deletions

diff --git a/js/codemirror/addon/lint/lint.css b/js/codemirror/addon/lint/lint.css
new file mode 100644
index 0000000000..ca59a6f1ff
--- /dev/null
+++ b/js/codemirror/addon/lint/lint.css
@@ -0,0 +1,77 @@
+/* The lint marker gutter */
+.CodeMirror-lint-markers {
+  width: 16px;
+}
+
+.CodeMirror-lint-tooltip {
+  background-color: infobackground;
+  border: 1px solid black;
+  border-radius: 4px 4px 4px 4px;
+  color: infotext;
+  font-size: 10pt;
+  overflow: hidden;
+  padding: 2px 5px;
+  position: fixed;
+  white-space: pre;
+  white-space: pre-wrap;
+  z-index: 100;
+  max-width: 600px;
+  opacity: 0;
+  transition: opacity .4s;
+  -moz-transition: opacity .4s;
+  -webkit-transition: opacity .4s;
+  -o-transition: opacity .4s;
+  -ms-transition: opacity .4s;
+}
+
+.CodeMirror-lint-tooltip code {
+  font-family: monospace;
+  font-weight: bold;
+}
+
+.CodeMirror-lint-mark-error, .CodeMirror-lint-mark-warning {
+  background-position: left bottom;
+  background-repeat: repeat-x;
+}
+
+.CodeMirror-lint-mark-error {
+  background-image:
+  url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAADCAYAAAC09K7GAAAAAXNSR0IArs4c6QAAAAZiS0dEAP8A/wD/oL2nkwAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9sJDw4cOCW1/KIAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAAHElEQVQI12NggIL/DAz/GdA5/xkY/qPKMDAwAADLZwf5rvm+LQAAAABJRU5ErkJggg==")
+  ;
+}
+
+.CodeMirror-lint-mark-warning {
+  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAADCAYAAAC09K7GAAAAAXNSR0IArs4c6QAAAAZiS0dEAP8A/wD/oL2nkwAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9sJFhQXEbhTg7YAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAAMklEQVQI12NkgIIvJ3QXMjAwdDN+OaEbysDA4MPAwNDNwMCwiOHLCd1zX07o6kBVGQEAKBANtobskNMAAAAASUVORK5CYII=");
+}
+
+.CodeMirror-lint-marker-error, .CodeMirror-lint-marker-warning {
+  background-position: center center;
+  background-repeat: no-repeat;
+  cursor: pointer;
+  display: inline-block;
+  height: 16px;
+  width: 16px;
+  vertical-align: middle;
+  position: relative;
+}
+
+.CodeMirror-lint-message-error, .CodeMirror-lint-message-warning {
+  padding-left: 18px;
+  background-position: top left;
+  background-repeat: no-repeat;
+}
+
+.CodeMirror-lint-marker-error, .CodeMirror-lint-message-error {
+  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAMAAAAoLQ9TAAAAHlBMVEW7AAC7AACxAAC7AAC7AAAAAAC4AAC5AAD///+7AAAUdclpAAAABnRSTlMXnORSiwCK0ZKSAAAATUlEQVR42mWPOQ7AQAgDuQLx/z8csYRmPRIFIwRGnosRrpamvkKi0FTIiMASR3hhKW+hAN6/tIWhu9PDWiTGNEkTtIOucA5Oyr9ckPgAWm0GPBog6v4AAAAASUVORK5CYII=");
+}
+
+.CodeMirror-lint-marker-warning, .CodeMirror-lint-message-warning {
+  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAMAAAAoLQ9TAAAANlBMVEX/uwDvrwD/uwD/uwD/uwD/uwD/uwD/uwD/uwD6twD/uwAAAADurwD2tQD7uAD+ugAAAAD/uwDhmeTRAAAADHRSTlMJ8mN1EYcbmiixgACm7WbuAAAAVklEQVR42n3PUQqAIBBFUU1LLc3u/jdbOJoW1P08DA9Gba8+YWJ6gNJoNYIBzAA2chBth5kLmG9YUoG0NHAUwFXwO9LuBQL1giCQb8gC9Oro2vp5rncCIY8L8uEx5ZkAAAAASUVORK5CYII=");
+}
+
+.CodeMirror-lint-marker-multiple {
+  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAcAAAAHCAMAAADzjKfhAAAACVBMVEUAAAAAAAC/v7914kyHAAAAAXRSTlMAQObYZgAAACNJREFUeNo1ioEJAAAIwmz/H90iFFSGJgFMe3gaLZ0od+9/AQZ0ADosbYraAAAAAElFTkSuQmCC");
+  background-repeat: no-repeat;
+  background-position: right bottom;
+  width: 100%; height: 100%;
+}
diff --git a/js/codemirror/addon/lint/lint.js b/js/codemirror/addon/lint/lint.js
new file mode 100644
index 0000000000..fc4a636320
--- /dev/null
+++ b/js/codemirror/addon/lint/lint.js
@@ -0,0 +1,209 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+(function(mod) {
+  if (typeof exports == "object" && typeof module == "object") // CommonJS
+    mod(require("../../lib/codemirror"));
+  else if (typeof define == "function" && define.amd) // AMD
+    define(["../../lib/codemirror"], mod);
+  else // Plain browser env
+    mod(CodeMirror);
+})(function(CodeMirror) {
+  "use strict";
+  var GUTTER_ID = "CodeMirror-lint-markers";
+
+  function showTooltip(e, content) {
+    var tt = document.createElement("div");
+    tt.className = "CodeMirror-lint-tooltip";
+    tt.appendChild(content.cloneNode(true));
+    document.body.appendChild(tt);
+
+    function position(e) {
+      if (!tt.parentNode) return CodeMirror.off(document, "mousemove", position);
+      tt.style.top = Math.max(0, e.clientY - tt.offsetHeight - 5) + "px";
+      tt.style.left = (e.clientX + 5) + "px";
+    }
+    CodeMirror.on(document, "mousemove", position);
+    position(e);
+    if (tt.style.opacity != null) tt.style.opacity = 1;
+    return tt;
+  }
+  function rm(elt) {
+    if (elt.parentNode) elt.parentNode.removeChild(elt);
+  }
+  function hideTooltip(tt) {
+    if (!tt.parentNode) return;
+    if (tt.style.opacity == null) rm(tt);
+    tt.style.opacity = 0;
+    setTimeout(function() { rm(tt); }, 600);
+  }
+
+  function showTooltipFor(e, content, node) {
+    var tooltip = showTooltip(e, content);
+    function hide() {
+      CodeMirror.off(node, "mouseout", hide);
+      if (tooltip) { hideTooltip(tooltip); tooltip = null; }
+    }
+    var poll = setInterval(function() {
+      if (tooltip) for (var n = node;; n = n.parentNode) {
+        if (n && n.nodeType == 11) n = n.host;
+        if (n == document.body) return;
+        if (!n) { hide(); break; }
+      }
+      if (!tooltip) return clearInterval(poll);
+    }, 400);
+    CodeMirror.on(node, "mouseout", hide);
+  }
+
+  function LintState(cm, options, hasGutter) {
+    this.marked = [];
+    this.options = options;
+    this.timeout = null;
+    this.hasGutter = hasGutter;
+    this.onMouseOver = function(e) { onMouseOver(cm, e); };
+  }
+
+  function parseOptions(_cm, options) {
+    if (options instanceof Function) return {getAnnotations: options};
+    if (!options || options === true) options = {};
+    return options;
+  }
+
+  function clearMarks(cm) {
+    var state = cm.state.lint;
+    if (state.hasGutter) cm.clearGutter(GUTTER_ID);
+    for (var i = 0; i < state.marked.length; ++i)
+      state.marked[i].clear();
+    state.marked.length = 0;
+  }
+
+  function makeMarker(labels, severity, multiple, tooltips) {
+    var marker = document.createElement("div"), inner = marker;
+    marker.className = "CodeMirror-lint-marker-" + severity;
+    if (multiple) {
+      inner = marker.appendChild(document.createElement("div"));
+      inner.className = "CodeMirror-lint-marker-multiple";
+    }
+
+    if (tooltips != false) CodeMirror.on(inner, "mouseover", function(e) {
+      showTooltipFor(e, labels, inner);
+    });
+
+    return marker;
+  }
+
+  function getMaxSeverity(a, b) {
+    if (a == "error") return a;
+    else return b;
+  }
+
+  function groupByLine(annotations) {
+    var lines = [];
+    for (var i = 0; i < annotations.length; ++i) {
+      var ann = annotations[i], line = ann.from.line;
+      (lines[line] || (lines[line] = [])).push(ann);
+    }
+    return lines;
+  }
+
+  function annotationTooltip(ann) {
+    var severity = ann.severity;
+    if (!severity) severity = "error";
+    var tip = document.createElement("div");
+    tip.className = "CodeMirror-lint-message-" + severity;
+    tip.appendChild(document.createTextNode(ann.message));
+    // Unescaping only the <code> tag.
+    tip.innerHTML = tip.innerHTML.replace("&lt;code&gt;", "<code>")
+      .replace("&lt;/code&gt;", "</code>");
+    return tip;
+  }
+
+  function startLinting(cm) {
+    var state = cm.state.lint, options = state.options;
+    var passOptions = options.options || options; // Support deprecated passing of `options` property in options
+    var getAnnotations = options.getAnnotations || cm.getHelper(CodeMirror.Pos(0, 0), "lint");
+    if (!getAnnotations) return;
+    if (options.async || getAnnotations.async)
+      getAnnotations(cm.getValue(), updateLinting, passOptions, cm);
+    else
+      updateLinting(cm, getAnnotations(cm.getValue(), passOptions, cm));
+  }
+
+  function updateLinting(cm, annotationsNotSorted) {
+    clearMarks(cm);
+    var state = cm.state.lint, options = state.options;
+
+    var annotations = groupByLine(annotationsNotSorted);
+
+    for (var line = 0; line < annotations.length; ++line) {
+      var anns = annotations[line];
+      if (!anns) continue;
+
+      var maxSeverity = null;
+      var tipLabel = state.hasGutter && document.createDocumentFragment();
+
+      for (var i = 0; i < anns.length; ++i) {
+        var ann = anns[i];
+        var severity = ann.severity;
+        if (!severity) severity = "error";
+        maxSeverity = getMaxSeverity(maxSeverity, severity);
+
+        if (options.formatAnnotation) ann = options.formatAnnotation(ann);
+        if (state.hasGutter) tipLabel.appendChild(annotationTooltip(ann));
+
+        if (ann.to) state.marked.push(cm.markText(ann.from, ann.to, {
+          className: "CodeMirror-lint-mark-" + severity,
+          __annotation: ann
+        }));
+      }
+
+      if (state.hasGutter)
+        cm.setGutterMarker(line, GUTTER_ID, makeMarker(tipLabel, maxSeverity, anns.length > 1,
+                                                       state.options.tooltips));
+    }
+    if (options.onUpdateLinting) options.onUpdateLinting(annotationsNotSorted, annotations, cm);
+  }
+
+  function onChange(cm) {
+    var state = cm.state.lint;
+    if (!state) return;
+    clearTimeout(state.timeout);
+    state.timeout = setTimeout(function(){startLinting(cm);}, state.options.delay || 500);
+  }
+
+  function popupSpanTooltip(ann, e) {
+    var target = e.target || e.srcElement;
+    showTooltipFor(e, annotationTooltip(ann), target);
+  }
+
+  function onMouseOver(cm, e) {
+    var target = e.target || e.srcElement;
+    if (!/\bCodeMirror-lint-mark-/.test(target.className)) return;
+    var box = target.getBoundingClientRect(), x = (box.left + box.right) / 2, y = (box.top + box.bottom) / 2;
+    var spans = cm.findMarksAt(cm.coordsChar({left: x, top: y}, "client"));
+    for (var i = 0; i < spans.length; ++i) {
+      var ann = spans[i].__annotation;
+      if (ann) return popupSpanTooltip(ann, e);
+    }
+  }
+
+  CodeMirror.defineOption("lint", false, function(cm, val, old) {
+    if (old && old != CodeMirror.Init) {
+      clearMarks(cm);
+      cm.off("change", onChange);
+      CodeMirror.off(cm.getWrapperElement(), "mouseover", cm.state.lint.onMouseOver);
+      clearTimeout(cm.state.lint.timeout);
+      delete cm.state.lint;
+    }
+
+    if (val) {
+      var gutters = cm.getOption("gutters"), hasLintGutter = false;
+      for (var i = 0; i < gutters.length; ++i) if (gutters[i] == GUTTER_ID) hasLintGutter = true;
+      var state = cm.state.lint = new LintState(cm, parseOptions(cm, val), hasLintGutter);
+      cm.on("change", onChange);
+      if (state.options.tooltips != false)
+        CodeMirror.on(cm.getWrapperElement(), "mouseover", state.onMouseOver);
+
+      startLinting(cm);
+    }
+  });
+});
diff --git a/js/codemirror/addon/lint/sql-lint.js b/js/codemirror/addon/lint/sql-lint.js
new file mode 100644
index 0000000000..557d3a478c
--- /dev/null
+++ b/js/codemirror/addon/lint/sql-lint.js
@@ -0,0 +1,37 @@
+CodeMirror.sqlLint = function(text, updateLinting, options, cm) {
+
+    // Skipping check if text box is empty.
+    if(text.trim() == "") {
+        updateLinting(cm, []);
+        return;
+    }
+
+    function handleResponse(json) {
+        response = JSON.parse(json);
+
+        var found = [];
+        for (var idx in response) {
+            found.push({
+                from: CodeMirror.Pos(
+                    response[idx].fromLine, response[idx].fromColumn
+                ),
+                to: CodeMirror.Pos(
+                    response[idx].toLine, response[idx].toColumn
+                ),
+                message: response[idx].message,
+                severity : response[idx].severity
+            });
+        }
+
+        updateLinting(cm, found);
+    }
+
+    $.ajax({
+        method: "POST",
+        url: "lint.php",
+        data: {
+            'sql_query': text
+        },
+        success: handleResponse
+    });
+}
diff --git a/js/functions.js b/js/functions.js
index 531994079a..b889eeedee 100644
--- a/js/functions.js
+++ b/js/functions.js
@@ -112,6 +112,17 @@ function PMA_getSQLEditor($textarea, options, resize) {
             mode: "text/x-mysql",
             lineWrapping: true
         };
+
+        if (CodeMirror.sqlLint) {
+            $.extend(defaults, {
+                gutters: ["CodeMirror-lint-markers"],
+                lint: {
+                    "getAnnotations": CodeMirror.sqlLint,
+                    "async": true,
+                }
+            });
+        }
+
         $.extend(true, defaults, options);
 
         // create CodeMirror editor
diff --git a/libraries/Header.class.php b/libraries/Header.class.php
index f138679be1..00da50a661 100644
--- a/libraries/Header.class.php
+++ b/libraries/Header.class.php
@@ -407,6 +407,10 @@ class PMA_Header
                     $this->_scripts->addFile('codemirror/addon/runmode/runmode.js');
                     $this->_scripts->addFile('codemirror/addon/hint/show-hint.js');
                     $this->_scripts->addFile('codemirror/addon/hint/sql-hint.js');
+                    if ($GLOBALS['cfg']['LintEnable']) {
+                        $this->_scripts->addFile('codemirror/addon/lint/lint.js');
+                        $this->_scripts->addFile('codemirror/addon/lint/sql-lint.js');
+                    }
                 }
                 $this->_scripts->addCode(
                     'ConsoleEnterExecutes='
@@ -659,6 +663,8 @@ class PMA_Header
             $retval .= '<link rel="stylesheet" type="text/css" href="'
                 . $basedir . 'js/codemirror/addon/hint/show-hint.css" />';
             $retval .= '<link rel="stylesheet" type="text/css" href="'
+                . $basedir . 'js/codemirror/addon/lint/lint.css" />';
+            $retval .= '<link rel="stylesheet" type="text/css" href="'
                 . $basedir . 'phpmyadmin.css.php?'
                 . 'nocache=' . $theme_id . $GLOBALS['text_dir'] . '" />';
             // load Print view's CSS last, so that it overrides all other CSS while 'printing'
diff --git a/libraries/Linter.class.php b/libraries/Linter.class.php
new file mode 100644
index 0000000000..5315ce479f
--- /dev/null
+++ b/libraries/Linter.class.php
@@ -0,0 +1,162 @@
+<?php
+/* vim: set expandtab sw=4 ts=4 sts=4: */
+/**
+ * Analyzes a query and gives user feedback.
+ *
+ * @package PhpMyAdmin
+ */
+if (! defined('PHPMYADMIN')) {
+    exit;
+}
+
+/**
+ * The linter itself.
+ *
+ * @package PhpMyAdmin
+ */
+class PMA_Linter
+{
+
+    /**
+     * Gets the starting position of each line.
+     *
+     * @param string $str String to be analyzed.
+     *
+     * @return array
+     */
+    public static function getLines($str)
+    {
+        $lines = array(0);
+
+        // The reason for using the '8bit' parameter is that the length
+        // required is the length in bytes, not characters.
+        //
+        // Given the following string: `????+`, where `?` represents a
+        // multi-byte character (lets assume that every `?` is a 2-byte
+        // character) and `+` is a newline, the first value of `$i` is `0` and
+        // the last one is `4` (because there are 5 characters). Bytes `$str[0]`
+        // and `$str[1]` are the first character, `$str[2]` and `$str[3]` are
+        // the second one and `$str[4]` is going to be the first byte of the
+        // third character. The fourth and the last one (which is actually a new
+        // line) aren't going to be processed at all.
+        for ($i = 0, $len = /*overload*/mb_strlen($str, '8bit'); $i < $len; ++$i) {
+            if ($str[$i] === "\n") {
+                $lines[] = $i + 1;
+            }
+        }
+        return $lines;
+    }
+
+    /**
+     * Computes the number of the line and column given an absolute position.
+     *
+     * @param array $lines The starting position of each line.
+     * @param int   $pos   The absolute position
+     *
+     * @return void
+     */
+    public static function findLineNumberAndColumn($lines, $pos)
+    {
+        $line = 0;
+        foreach ($lines as $lineNo => $lineStart) {
+            if ($lineStart > $pos) {
+                break;
+            }
+            $line = $lineNo;
+        }
+        return array($line, $pos - $lines[$line]);
+    }
+
+    /**
+     * Runs the linting process.
+     *
+     * @param string $query The query to be checked.
+     *
+     * @return void
+     */
+    public static function lint($query)
+    {
+        // Disabling lint for huge queries to save some resources.
+        if (/*overload*/mb_strlen($query) > 10000) {
+            echo json_encode(
+                array(
+                    array(
+                        'message' => 'The linting is disabled for this query because it exceededs the maxmimum length.',
+                        'fromLine' => 0,
+                        'fromColumn' => 0,
+                        'toLine' => 0,
+                        'toColumn' => 0,
+                        'severity' => 'warning',
+                    )
+                )
+            );
+            return;
+        }
+
+        /**
+         * Lexer used for tokenizing the query.
+         *
+         * @var SqlParser\Lexer
+         */
+        $lexer = new SqlParser\Lexer($query);
+
+        /**
+         * Parsed used for analysing the query.
+         *
+         * @var SqlParser\Parser
+         */
+        $parser = new SqlParser\Parser($lexer->list);
+
+        /**
+         * Array containing all errors.
+         *
+         * @var array
+         */
+        $errors = SqlParser\Utils\Error::get(array($lexer, $parser));
+
+        /**
+         * The response containing of all errors.
+         *
+         * @var array
+         */
+        $response = array();
+
+        /**
+         * The starting position for each line.
+         *
+         * CodeMirror requires relative position to line, but the parser stores
+         * only the absolute position of the character in string.
+         *
+         * @var array
+         */
+        $lines = static::getLines($query);
+
+        // Building the response.
+        foreach ($errors as $idx => $error) {
+
+            // Starting position of the string that caused the error.
+            list($fromLine, $fromColumn) = static::findLineNumberAndColumn(
+                $lines, $error[3]
+            );
+
+            // Ending position of the string that caused the error.
+            list($toLine, $toColumn) = static::findLineNumberAndColumn(
+                $lines, $error[3] + /*overload*/mb_strlen($error[2])
+            );
+
+            // Building the response.
+            $response[] = array(
+                'message' => $error[0] . ' (near <code>' . $error[2] . '</code>)',
+                'fromLine' => $fromLine,
+                'fromColumn' => $fromColumn,
+                'toLine' => $toLine,
+                'toColumn' => $toColumn,
+                'severity' => 'error',
+            );
+        }
+
+        // Sending back the answer.
+        echo json_encode($response);
+    }
+
+}
\ No newline at end of file
diff --git a/libraries/config.default.php b/libraries/config.default.php
index 4a5195d442..7e5c6c8ec3 100644
--- a/libraries/config.default.php
+++ b/libraries/config.default.php
@@ -758,6 +758,13 @@ $cfg['RetainQueryBox'] = false;
 $cfg['CodemirrorEnable'] = true;
 
 /**
+ * use the parser to find any errors in the query before executing
+ *
+ * @global boolean $cfg['LintEnable']
+ */
+$cfg['LintEnable'] = true;
+
+/**
  * show a 'Drop database' link to normal users
  *
  * @global boolean $cfg['AllowUserDropDatabase']
diff --git a/libraries/config/messages.inc.php b/libraries/config/messages.inc.php
index 583678ff13..d70b19706e 100644
--- a/libraries/config/messages.inc.php
+++ b/libraries/config/messages.inc.php
@@ -57,6 +57,9 @@ $strConfigCodemirrorEnable_desc = __(
     . 'line numbers.'
 );
 $strConfigCodemirrorEnable_name = __('Enable CodeMirror');
+$strConfigLintEnable_desc = __('Find any erorors in the query before executing it.'
+    . 'Requires CodeMirror to be enabled.');
+$strConfigLintEnable_name = __('Enable linter');
 $strConfigMinSizeForInputField_desc = __(
     'Defines the minimum size for input fields generated for CHAR and VARCHAR '
     . 'columns.'
diff --git a/libraries/config/setup.forms.php b/libraries/config/setup.forms.php
index 304919c940..5ab03c8b27 100644
--- a/libraries/config/setup.forms.php
+++ b/libraries/config/setup.forms.php
@@ -162,6 +162,7 @@ $forms['Sql_queries']['Sql_queries'] = array(
     'MaxCharactersInDisplayedSQL',
     'RetainQueryBox',
     'CodemirrorEnable',
+    'LintEnable',
     'EnableAutocompleteForTablesAndColumns',
     'DefaultForeignKeyChecks');
 $forms['Sql_queries']['Sql_box'] = array('SQLQuery' => array(
diff --git a/libraries/config/user_preferences.forms.php b/libraries/config/user_preferences.forms.php
index c150905a6e..d51acd25d0 100644
--- a/libraries/config/user_preferences.forms.php
+++ b/libraries/config/user_preferences.forms.php
@@ -70,6 +70,7 @@ $forms['Sql_queries']['Sql_queries'] = array(
     'MaxCharactersInDisplayedSQL',
     'RetainQueryBox',
     'CodemirrorEnable',
+    'LintEnable',
     'EnableAutocompleteForTablesAndColumns',
     'DefaultForeignKeyChecks');
 $forms['Sql_queries']['Sql_box'] = array(
diff --git a/libraries/sql-parser/src/Components/AlterOperation.php b/libraries/sql-parser/src/Components/AlterOperation.php
index 7c528283be..9f859e2787 100644
--- a/libraries/sql-parser/src/Components/AlterOperation.php
+++ b/libraries/sql-parser/src/Components/AlterOperation.php
@@ -139,12 +139,19 @@ class AlterOperation extends Component
                 break;
             }
 
-            // Skipping whitespaces and comments.
-            if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
-                if ($state !== 2) {
-                    // State 2 parses the unknown part which must include whitespaces as well.
-                    continue;
+            // Skipping comments.
+            if ($token->type === Token::TYPE_COMMENT) {
+                continue;
+            }
+
+            // Skipping whitespaces.
+            if ($token->type === Token::TYPE_WHITESPACE) {
+                if ($state === 2) {
+                    // When parsing the unknown part, the whitespaces are
+                    // included to not break anything.
+                    $ret->unknown[] = $token;
                 }
+                continue;
             }
 
             if ($state === 0) {
@@ -179,6 +186,11 @@ class AlterOperation extends Component
             }
         }
 
+        if ($ret->options->isEmpty()) {
+            $parser->error('Unrecognized alter operation.', $list->tokens[$list->idx]);
+            return null;
+        }
+
         --$list->idx;
         return $ret;
     }
diff --git a/libraries/sql-parser/src/Components/Array2d.php b/libraries/sql-parser/src/Components/Array2d.php
index c521de2a16..117ad75624 100644
--- a/libraries/sql-parser/src/Components/Array2d.php
+++ b/libraries/sql-parser/src/Components/Array2d.php
@@ -26,39 +26,38 @@ class Array2d extends Component
 {
 
     /**
-     * An array with the values of the row to be inserted.
-     *
-     * @var array
-     */
-    public $values;
-
-    /**
      * @param Parser     $parser  The parser that serves as context.
      * @param TokensList $list    The list of tokens that are being parsed.
      * @param array      $options Parameters for parsing.
      *
-     * @return Array2d
+     * @return ArrayObj[]
      */
     public static function parse(Parser $parser, TokensList $list, array $options = array())
     {
         $ret = array();
 
-        $expr = new Array2d();
-        $value = '';
+        /**
+         * Whether an array was parsed or not. To be a valid parsing, at least
+         * one array must be parsed after each comma.
+         * @var bool $parsed
+         */
+        $parsed = false;
+
+        /**
+         * The number of values in each set.
+         * @var int
+         */
+        $count = -1;
 
         /**
          * The state of the parser.
          *
          * Below are the states of the parser.
          *
-         *      0 ------------------------[ ( ]-----------------------> 1
+         *      0 ----------------------[ array ]---------------------> 1
          *
-         *      1 ----------------------[ value ]---------------------> 2
-         *
-         *      2 ------------------------[ , ]-----------------------> 1
-         *      2 ------------------------[ ) ]-----------------------> 3
-         *
-         *      3 ---------------------[ options ]--------------------> 4
+         *      1 ------------------------[ , ]------------------------> 0
+         *      1 -----------------------[ else ]----------------------> -1
          *
          * @var int
          */
@@ -86,40 +85,36 @@ class Array2d extends Component
                 break;
             }
 
-            if ($token->type === Token::TYPE_OPERATOR) {
+            if ($state === 0) {
                 if ($token->value === '(') {
-                    $state = 1;
-                    continue;
-                } elseif ($token->value === ',') {
-                    if ($state !== 3) {
-                        $expr->values[] = $value;
-                        $value = '';
-                        $state = 1;
+                    $arr = ArrayObj::parse($parser, $list, $options);
+                    $arrCount = count($arr->values);
+                    if ($count === -1) {
+                        $count = $arrCount;
+                    } elseif ($arrCount != $count) {
+                        $parser->error("{$count} values were expected, but found {$arrCount}.", $token);
                     }
-                    continue;
-                } elseif ($token->value === ')') {
-                    $state = 3;
-                    $expr->values[] = $value;
-                    $ret[] = $expr;
-                    $value = '';
-                    $expr = new Array2d();
-                    continue;
+                    $ret[] = $arr;
+                    $parsed = true;
+                    $state = 1;
+                } else {
+                    break;
+                }
+            } elseif ($state === 1) {
+                if ($token->value === ',') {
+                    $parsed = false;
+                    $state = 0;
+                } else {
+                    break;
                 }
-
-                // No other operator is expected.
-                break;
-            }
-
-            if ($state === 1) {
-                $value .= $token->value;
-                $state = 2;
             }
-
         }
 
-        // Last iteration was not saved.
-        if (!empty($expr->values)) {
-            $ret[] = $expr;
+        if (!$parsed) {
+            $parser->error(
+                'An opening bracket followed by a set of values was expected.',
+                $list->tokens[$list->idx]
+            );
         }
 
         --$list->idx;
diff --git a/libraries/sql-parser/src/Components/ArrayObj.php b/libraries/sql-parser/src/Components/ArrayObj.php
index 01571defa3..d38077c88d 100644
--- a/libraries/sql-parser/src/Components/ArrayObj.php
+++ b/libraries/sql-parser/src/Components/ArrayObj.php
@@ -97,7 +97,7 @@ class ArrayObj extends Component
 
             if ($state === 0) {
                 if (($token->type !== Token::TYPE_OPERATOR) || ($token->value !== '(')) {
-                    $parser->error('An open bracket was expected.', $token);
+                    $parser->error('An opening bracket was expected.', $token);
                     break;
                 }
                 $state = 1;
@@ -111,7 +111,7 @@ class ArrayObj extends Component
                 $state = 2;
             } elseif ($state === 2) {
                 if (($token->type !== Token::TYPE_OPERATOR) || (($token->value !== ',') && ($token->value !== ')'))) {
-                    $parser->error('Symbols \')\' or \',\' were expected', $token);
+                    $parser->error('A comma or a closing bracket was expected', $token);
                     break;
                 }
                 if ($token->value === ',') {
diff --git a/libraries/sql-parser/src/Components/Expression.php b/libraries/sql-parser/src/Components/Expression.php
index 065810c523..964ceb931c 100644
--- a/libraries/sql-parser/src/Components/Expression.php
+++ b/libraries/sql-parser/src/Components/Expression.php
@@ -126,9 +126,9 @@ class Expression extends Component
 
         /**
          * Whether a period was previously found.
-         * @var bool $period
+         * @var bool $dot
          */
-        $period = false;
+        $dot = false;
 
         /**
          * Whether an alias is expected. Is 2 if `AS` keyword was found.
@@ -146,7 +146,7 @@ class Expression extends Component
          * Keeps track of the previous token.
          * Possible values:
          *     string, if function was previously found;
-         *     true, if open bracket was previously found;
+         *     true, if opening bracket was previously found;
          *     null, in any other case.
          * @var string|bool $prev
          */
@@ -169,7 +169,7 @@ class Expression extends Component
                 if (($isExpr) && (!$alias)) {
                     $ret->expr .= $token->token;
                 }
-                if (($alias === 0) && (empty($options['noAlias'])) && (!$isExpr) && (!$period) && (!empty($ret->expr))) {
+                if (($alias === 0) && (empty($options['noAlias'])) && (!$isExpr) && (!$dot) && (!empty($ret->expr))) {
                     $alias = 1;
                 }
                 continue;
@@ -202,9 +202,6 @@ class Expression extends Component
                 }
                 if ($token->value === '(') {
                     ++$brackets;
-                    // We don't check to see if `$prev` is `true` (open bracket
-                    // was found before) because the brackets count is one (the
-                    // only bracket we found is this one).
                     if ((empty($ret->function)) && ($prev !== null) && ($prev !== true)) {
                         // A function name was previously found and now an open
                         // bracket, so this is a function call.
@@ -222,7 +219,7 @@ class Expression extends Component
                             break;
                         }
                     } elseif ($brackets < 0) {
-                        $parser->error('Unexpected bracket.', $token);
+                        $parser->error('Unexpected closing bracket.', $token);
                         $brackets = 0;
                     }
                 } elseif ($token->value === ',') {
@@ -250,28 +247,36 @@ class Expression extends Component
                         // Found a `.` which means we expect a column name and
                         // the column name we parsed is actually the table name
                         // and the table name is actually a database name.
-                        if ((!empty($ret->database)) || ($period)) {
+                        if ((!empty($ret->database)) || ($dot)) {
                             $parser->error('Unexpected dot.', $token);
                         }
                         $ret->database = $ret->table;
                         $ret->table = $ret->column;
                         $ret->column = null;
-                        $period = true;
+                        $dot = true;
                     } else {
                         // We found the name of a column (or table if column
                         // field should be skipped; used to parse table names).
-                        if (!empty($options['skipColumn'])) {
-                            if (!empty($ret->table)) {
+                        $field = (!empty($options['skipColumn'])) ? 'table' : 'column';
+                        if (!empty($ret->$field)) {
+
+                            // No alias is expected.
+                            if (!empty($options['noAlias'])) {
                                 break;
                             }
-                            $ret->table = $token->value;
-                        } else {
-                            if (!empty($ret->column)) {
-                                break;
+
+                            // Parsing aliases without `AS` keyword and any whitespace.
+                            // Example: SELECT 1`foo`
+                            if (($token->type === Token::TYPE_STRING)
+                                || (($token->type === Token::TYPE_SYMBOL)
+                                && ($token->flags & Token::FLAG_SYMBOL_BACKTICK))
+                            ) {
+                                $ret->alias = $token->value;
                             }
-                            $ret->column = $token->value;
+                        } else {
+                            $ret->$field = $token->value;
                         }
-                        $period = false;
+                        $dot = false;
                     }
                 } else {
                     // Parsing aliases without `AS` keyword.
@@ -298,9 +303,8 @@ class Expression extends Component
             }
 
         }
-
         if ($alias === 2) {
-            $parser->error('Alias was expected.');
+            $parser->error('An alias was expected.', $list->tokens[$list->idx - 1]);
         }
 
         // Whitespaces might be added at the end.
diff --git a/libraries/sql-parser/src/Components/FieldDefinition.php b/libraries/sql-parser/src/Components/FieldDefinition.php
index 0217964068..4df98cb2a5 100644
--- a/libraries/sql-parser/src/Components/FieldDefinition.php
+++ b/libraries/sql-parser/src/Components/FieldDefinition.php
@@ -36,6 +36,11 @@ class FieldDefinition extends Component
      * @var array
      */
     public static $FIELD_OPTIONS = array(
+
+        // Tells the `OptionsArray` to not sort the options.
+        // See the note below.
+        '_UNSORTED'                     => true,
+
         'NOT NULL'                      => 1,
         'NULL'                          => 1,
         'DEFAULT'                       => array(2, 'var'),
@@ -48,13 +53,26 @@ class FieldDefinition extends Component
         'COLUMN_FORMAT'                 => array(6, 'var'),
         'ON UPDATE'                     => array(7, 'var'),
 
-        // MariaDB options.
-        'GENERATED ALWAYS'              => 1,
-        'AS'                            => array(2, 'expr', array('bracketsDelimited' => true)),
-        'VIRTUAL'                       => 3,
-        'PERSISTENT'                    => 3,
-        // 'UNIQUE'                        => 4, // common
-        // 'UNIQUE KEY'                    => 4, // common
+        // Generated columns options.
+        'GENERATED ALWAYS'              => 8,
+        'AS'                            => array(9, 'expr', array('bracketsDelimited' => true)),
+        'VIRTUAL'                       => 10,
+        'PERSISTENT'                    => 11,
+        'STORED'                        => 11,
+        // Common entries.
+        //
+        // NOTE: Some of the common options are not in the same order which
+        // causes troubles when checking if the options are in the right order.
+        // I should find a way to define multiple sets of options and make the
+        // parser select the right set.
+        //
+        // 'UNIQUE'                        => 4,
+        // 'UNIQUE KEY'                    => 4,
+        // 'COMMENT'                       => array(5, 'var'),
+        // 'NOT NULL'                      => 1,
+        // 'NULL'                          => 1,
+        // 'PRIMARY'                       => 4,
+        // 'PRIMARY KEY'                   => 4,
     );
 
     /**
@@ -153,7 +171,7 @@ class FieldDefinition extends Component
          *      4 --------------------[ REFERENCES ]------------------> 4
          *
          *      5 ------------------------[ , ]-----------------------> 1
-         *      5 ------------------------[ ) ]-----------------------> -1
+         *      5 ------------------------[ ) ]-----------------------> 6 (-1)
          *
          * @var int
          */
@@ -179,6 +197,9 @@ class FieldDefinition extends Component
             if ($state === 0) {
                 if (($token->type === Token::TYPE_OPERATOR) && ($token->value === '(')) {
                     $state = 1;
+                } else {
+                    $parser->error('An opening bracket was expected.', $token);
+                    break;
                 }
             } elseif ($state === 1) {
                 if (($token->type === Token::TYPE_KEYWORD) && ($token->value === 'CONSTRAINT')) {
@@ -213,13 +234,12 @@ class FieldDefinition extends Component
                 $expr = new FieldDefinition();
                 if ($token->value === ',') {
                     $state = 1;
-                    continue;
                 } elseif ($token->value === ')') {
+                    $state = 6;
                     ++$list->idx;
                     break;
                 }
             }
-
         }
 
         // Last iteration was not saved.
@@ -227,12 +247,16 @@ class FieldDefinition extends Component
             $ret[] = $expr;
         }
 
+        if (($state !== 0) && ($state !== 6)) {
+            $parser->error('A closing bracket was expected.', $list->tokens[$list->idx - 1]);
+        }
+
         --$list->idx;
         return $ret;
     }
 
     /**
-     * @param FieldDefinition[] $component The component to be built.
+     * @param FieldDefinition|FieldDefinition[] $component The component to be built.
      *
      * @return string
      */
diff --git a/libraries/sql-parser/src/Components/Limit.php b/libraries/sql-parser/src/Components/Limit.php
index 1e25d2aedd..86ab55afb7 100644
--- a/libraries/sql-parser/src/Components/Limit.php
+++ b/libraries/sql-parser/src/Components/Limit.php
@@ -87,7 +87,7 @@ class Limit extends Component
 
             if (($token->type === Token::TYPE_KEYWORD) && ($token->value === 'OFFSET')) {
                 if ($offset) {
-                    $parser->error('An offset was expected.');
+                    $parser->error('An offset was expected.', $token);
                 }
                 $offset = true;
                 continue;
@@ -108,7 +108,7 @@ class Limit extends Component
         }
 
         if ($offset) {
-            $parser->error('An offset was expected.');
+            $parser->error('An offset was expected.', $list->tokens[$list->idx - 1]);
         }
 
         --$list->idx;
diff --git a/libraries/sql-parser/src/Components/OptionsArray.php b/libraries/sql-parser/src/Components/OptionsArray.php
index aabb807488..487eefd4d2 100644
--- a/libraries/sql-parser/src/Components/OptionsArray.php
+++ b/libraries/sql-parser/src/Components/OptionsArray.php
@@ -36,7 +36,8 @@ class OptionsArray extends Component
      * Constructor.
      *
      * @param array $options The array of options. Options that have a value
-     *                       must be an array with two keys 'name' and 'value'.
+     *                       must be an array with at least two keys `name` and
+     *                       `expr` or `value`.
      */
     public function __construct(array $options = array())
     {
@@ -162,11 +163,11 @@ class OptionsArray extends Component
                         'name' => $token->value,
                         // @var bool Whether it contains an equal sign.
                         //           This is used by the builder to rebuild it.
-                        'equal' => $lastOption[1] === 'var=',
+                        'equals' => $lastOption[1] === 'var=',
                         // @var string Raw value.
-                        'value' => '',
+                        'expr' => '',
                         // @var string Processed value.
-                        'value_' => '',
+                        'value' => '',
                     );
                     $state = 1;
                 } elseif ($lastOption[1] === 'expr') {
@@ -179,14 +180,14 @@ class OptionsArray extends Component
                         // @var string The name of the option.
                         'name' => $token->value,
                         // @var Expression The parsed expression.
-                        'value' => null,
+                        'expr' => null,
                     );
                     $state = 1;
                 }
             } elseif ($state === 1) {
                 $state = 2;
                 if ($token->value === '=') {
-                    $ret->options[$lastOptionId]['equal'] = true;
+                    $ret->options[$lastOptionId]['equals'] = true;
                     continue;
                 }
             }
@@ -195,11 +196,13 @@ class OptionsArray extends Component
             // change this iteration.
             if ($state === 2) {
                 if ($lastOption[1] === 'expr') {
-                    $ret->options[$lastOptionId]['value'] = Expression::parse(
+                    $ret->options[$lastOptionId]['expr'] = Expression::parse(
                         $parser,
                         $list,
                         empty($lastOption[2]) ? array() : $lastOption[2]
                     );
+                    $ret->options[$lastOptionId]['value']
+                        = $ret->options[$lastOptionId]['expr']->expr;
                     $lastOption = null;
                     $state = 0;
                 } else {
@@ -209,11 +212,14 @@ class OptionsArray extends Component
                         --$brackets;
                     }
 
-                    // Raw value.
-                    $ret->options[$lastOptionId]['value'] .= $token->token;
+                    $ret->options[$lastOptionId]['expr'] .= $token->token;
 
-                    // Processed value.
-                    $ret->options[$lastOptionId]['value_'] .= $token->value;
+                    if (!((($token->token === '(') && ($brackets === 1))
+                        || (($token->token === ')') && ($brackets === 0)))
+                    ) {
+                        // First pair of brackets is being skipped.
+                        $ret->options[$lastOptionId]['value'] .= $token->value;
+                    }
 
                     // Checking if we finished parsing.
                     if ($brackets === 0) {
@@ -223,7 +229,9 @@ class OptionsArray extends Component
             }
         }
 
-        ksort($ret->options);
+        if (empty($options['_UNSORTED'])) {
+            ksort($ret->options);
+        }
 
         --$list->idx;
         return $ret;
@@ -245,9 +253,9 @@ class OptionsArray extends Component
                 $options[] = $option;
             } else {
                 $options[] = $option['name']
-                    . (!empty($option['equal']) ? '=' : ' ')
-                    . ((string) $option['value']);
-                // If `$option['value']` happens to be a component, the magic
+                    . (!empty($option['equals']) ? '=' : ' ')
+                    . (!empty($option['expr']) ? ((string) $option['expr']) : $option['value']);
+                // If `$option['expr']` happens to be a component, the magic
                 // method will build it automatically.
             }
         }
@@ -257,17 +265,19 @@ class OptionsArray extends Component
     /**
      * Checks if it has the specified option and returns it value or true.
      *
-     * @param string $key The key to be checked.
+     * @param string $key     The key to be checked.
+     * @param bool   $getExpr Gets the expression instead of the value.
+     *                        The value is the processed form of the expression.
      *
      * @return mixed
      */
-    public function has($key)
+    public function has($key, $getExpr = false)
     {
         foreach ($this->options as $option) {
             if ($key === $option) {
                 return true;
             } elseif ((is_array($option)) && ($key === $option['name'])) {
-                return $option['value'];
+                return $getExpr ? $option['expr'] : $option['value'];
             }
         }
         return false;
@@ -309,4 +319,14 @@ class OptionsArray extends Component
             $this->options = array_merge_recursive($this->options, $options->options);
         }
     }
+
+    /**
+     * Checks tf there are no options set.
+     *
+     * @return bool
+     */
+    public function isEmpty()
+    {
+        return empty($this->options);
+    }
 }
diff --git a/libraries/sql-parser/src/Components/ParameterDefinition.php b/libraries/sql-parser/src/Components/ParameterDefinition.php
index db0f815c1e..d10a460f38 100644
--- a/libraries/sql-parser/src/Components/ParameterDefinition.php
+++ b/libraries/sql-parser/src/Components/ParameterDefinition.php
@@ -120,7 +120,6 @@ class ParameterDefinition extends Component
                 $expr = new ParameterDefinition();
                 if ($token->value === ',') {
                     $state = 1;
-                    continue;
                 } elseif ($token->value === ')') {
                     ++$list->idx;
                     break;
diff --git a/libraries/sql-parser/src/Components/RenameOperation.php b/libraries/sql-parser/src/Components/RenameOperation.php
index 335043791a..9a91f81b8f 100644
--- a/libraries/sql-parser/src/Components/RenameOperation.php
+++ b/libraries/sql-parser/src/Components/RenameOperation.php
@@ -53,6 +53,13 @@ class RenameOperation extends Component
         $expr = new RenameOperation();
 
         /**
+         * Whether an operation was parsed or not. To be a valid parsing, at
+         * least one operation must be parsed after each comma.
+         * @var bool $parsed
+         */
+        $parsed = false;
+
+        /**
          * The state of the parser.
          *
          * Below are the states of the parser.
@@ -87,29 +94,7 @@ class RenameOperation extends Component
                 continue;
             }
 
-            if (($token->type === Token::TYPE_KEYWORD) && ($token->flags & Token::FLAG_KEYWORD_RESERVED)) {
-                if (($state === 1) && ($token->value === 'TO')) {
-                    $state = 2;
-                    continue;
-                }
-
-                // No other keyword is expected.
-                break;
-            }
-
-            if ($token->type === Token::TYPE_OPERATOR) {
-                if (($state === 3) && ($token->value === ',')) {
-                    $ret[] = $expr;
-                    $expr = new RenameOperation();
-                    $state = 0;
-                    continue;
-                }
-
-                // No other operator is expected.
-                break;
-            }
-
-            if ($state == 0) {
+            if ($state === 0) {
                 $expr->old = Expression::parse(
                     $parser,
                     $list,
@@ -119,8 +104,18 @@ class RenameOperation extends Component
                         'skipColumn' => true,
                     )
                 );
+                if (empty($expr->old)) {
+                    $parser->error('The old name of the table was expected.', $token);
+                }
                 $state = 1;
-            } elseif ($state == 2) {
+            } elseif ($state === 1) {
+                if (($token->type === Token::TYPE_KEYWORD) && ($token->value === 'TO')) {
+                    $state = 2;
+                } else {
+                    $parser->error('Keyword "TO" was expected.', $token);
+                    break;
+                }
+            } elseif ($state === 2) {
                 $expr->new = Expression::parse(
                     $parser,
                     $list,
@@ -130,9 +125,26 @@ class RenameOperation extends Component
                         'noAlias' => true,
                     )
                 );
+                if (empty($expr->new)) {
+                    $parser->error('The new name of the table was expected.', $token);
+                }
                 $state = 3;
+                $parsed = true;
+            } elseif ($state === 3) {
+                if (($token->type === Token::TYPE_OPERATOR) && ($token->value === ',')) {
+                    $ret[] = $expr;
+                    $expr = new RenameOperation();
+                    $state = 0;
+                    // Found a comma, looking for another operation.
+                    $parsed = false;
+                } else {
+                    break;
+                }
             }
+        }
 
+        if (!$parsed) {
+            $parser->error('A rename operation was expected.', $list->tokens[$list->idx - 1]);
         }
 
         // Last iteration was not saved.
diff --git a/libraries/sql-parser/src/Components/SetOperation.php b/libraries/sql-parser/src/Components/SetOperation.php
index dad91e5425..a9e8ba1624 100644
--- a/libraries/sql-parser/src/Components/SetOperation.php
+++ b/libraries/sql-parser/src/Components/SetOperation.php
@@ -88,25 +88,23 @@ class SetOperation extends Component
                 break;
             }
 
-            if ($token->type === Token::TYPE_OPERATOR) {
-                if ($token->value === ',') {
+            if ($state === 0) {
+                if ($token->token === '=') {
+                    $state = 1;
+                } else {
+                    $expr->column .= $token->token;
+                }
+            } elseif ($state === 1) {
+                if ($token->token === ',') {
                     $expr->column = trim($expr->column);
                     $expr->value = trim($expr->value);
                     $ret[] = $expr;
                     $expr = new SetOperation();
                     $state = 0;
-                    continue;
-                } elseif ($token->value === '=') {
-                    $state = 1;
-                    continue;
+                } else {
+                    $expr->value .= $token->token;
                 }
             }
-
-            if ($state === 0) {
-                $expr->column .= $token->token;
-            } else { // } else if ($state === 1) {
-                $expr->value .= $token->token;
-            }
         }
 
         // Last iteration was not saved.
diff --git a/libraries/sql-parser/src/Context.php b/libraries/sql-parser/src/Context.php
index 7f937dc2c4..dd912fb279 100644
--- a/libraries/sql-parser/src/Context.php
+++ b/libraries/sql-parser/src/Context.php
@@ -397,7 +397,9 @@ abstract class Context
      */
     public static function isSeparator($str)
     {
-        return !ctype_alnum($str) && $str !== '_';
+        // NOTES:   Only ASCII characters may be separators.
+        //          `~` is the last printable ASCII character.
+        return ($str <= '~') && (!ctype_alnum($str)) && ($str !== '_');
     }
 
     /**
@@ -434,7 +436,7 @@ abstract class Context
      * Loads the context with the closest version to the one specified.
      *
      * The closest context is found by replacing last digits with zero until one
-     * is loaded succesfully.
+     * is loaded successfully.
      *
      * @see Context::load()
      *
@@ -448,13 +450,12 @@ abstract class Context
         /**
          * The number of replaces done by `preg_replace`.
          * This actually represents whether a new context was generated or not.
-         * @var int
+         * @var int $count
          */
         $count = 0;
 
-        // As long as a new context can be generated, we try to laod it.
+        // As long as a new context can be generated, we try to load it.
         do {
-            $loaded = true;
             try {
                 // Trying to load the new context.
                 static::load($context);
diff --git a/libraries/sql-parser/src/Lexer.php b/libraries/sql-parser/src/Lexer.php
index d70641fbdb..aae95f1a58 100644
--- a/libraries/sql-parser/src/Lexer.php
+++ b/libraries/sql-parser/src/Lexer.php
@@ -13,6 +13,23 @@ namespace SqlParser;
 
 use SqlParser\Exceptions\LexerException;
 
+if (!defined('USE_UTF_STRINGS')) {
+
+    /**
+     * Forces usage of `UtfString` if the string is multibyte.
+     * `UtfString` may be slower, but it gives better results.
+     * @var bool
+     */
+    define('USE_UTF_STRINGS', true);
+}
+
+// Set internal character to UTF-8.
+// In previous versions of PHP (5.5 and older) the default internal encoding is
+// "ISO-8859-1".
+if ((defined('USE_UTF_STRINGS')) && (USE_UTF_STRINGS)) {
+    mb_internal_encoding('UTF-8');
+}
+
 /**
  * Performs lexical analysis over a SQL statement and splits it in multiple
  * tokens.
@@ -149,11 +166,24 @@ class Lexer
      */
     public function __construct($str, $strict = false)
     {
+        // `strlen` is used instead of `mb_strlen` because the lexer needs to
+        // parse each byte of the input.
+        $len = ($str instanceof UtfString) ? $str->length() : strlen($str);
+
+        // For multi-byte strings, a new instance of `UtfString` is
+        // initialized (only if `UtfString` usage is forced.
+        if (!($str instanceof UtfString)) {
+            if ((USE_UTF_STRINGS) && ($len != mb_strlen($str))) {
+                $str = new UtfString($str);
+            }
+        }
+
         $this->str = $str;
-        $this->len = ($str instanceof UtfString) ?
-            $str->length() : strlen($str);
+        $this->len = ($str instanceof UtfString) ? $str->length() : $len;
+
         $this->strict = $strict;
 
+        // Setting the delimiter.
         $this->delimiter = static::$DEFAULT_DELIMITER;
 
         $this->lex();
diff --git a/libraries/sql-parser/src/Parser.php b/libraries/sql-parser/src/Parser.php
index 260ea25a53..f4763063f2 100644
--- a/libraries/sql-parser/src/Parser.php
+++ b/libraries/sql-parser/src/Parser.php
@@ -338,7 +338,7 @@ class Parser
             // Checking if it is a known statement that can be parsed.
             if (empty(static::$STATEMENT_PARSERS[$token->value])) {
                 $this->error(
-                    'Unrecognized statement type "' . $token->value . '".',
+                    'Unrecognized statement type.',
                     $token
                 );
                 // Skipping to the end of this statement.
@@ -376,6 +376,10 @@ class Parser
                 && ($lastStatement instanceof SelectStatement)
                 && ($stmt instanceof SelectStatement)
             ) {
+                /**
+                 * Last SELECT statement.
+                 * @var SelectStatement $lastStatement
+                 */
                 $lastStatement->union[] = $stmt;
                 $inUnion = false;
             } else {
diff --git a/libraries/sql-parser/src/Statement.php b/libraries/sql-parser/src/Statement.php
index 3739310224..4eb3ccbe63 100644
--- a/libraries/sql-parser/src/Statement.php
+++ b/libraries/sql-parser/src/Statement.php
@@ -244,7 +244,7 @@ abstract class Statement
                 // There is no parser for this keyword and isn't the beginning
                 // of a statement (so no options) either.
                 $parser->error(
-                    'Unrecognized keyword "' . $token->value . '".',
+                    'Unrecognized keyword.',
                     $token
                 );
                 continue;
@@ -300,8 +300,8 @@ abstract class Statement
      *
      * @return string
      */
-    public function __toString() 
+    public function __toString()
     {
-        return static::build($this);
+        return $this->build();
     }
 }
diff --git a/libraries/sql-parser/src/Statements/CreateStatement.php b/libraries/sql-parser/src/Statements/CreateStatement.php
index 8475448b41..afabc6a8c5 100644
--- a/libraries/sql-parser/src/Statements/CreateStatement.php
+++ b/libraries/sql-parser/src/Statements/CreateStatement.php
@@ -287,7 +287,15 @@ class CreateStatement extends Statement
                 'skipColumn' => true,
             )
         );
-        ++$list->idx; // Skipping field.
+
+        if (empty($this->name)) {
+            $parser->error(
+                'The name of the entity was expected.',
+                $list->tokens[$list->idx]
+            );
+        } else {
+            ++$list->idx; // Skipping field.
+        }
 
         if ($this->options->has('DATABASE')) {
             $this->entityOptions = OptionsArray::parse(
@@ -297,6 +305,12 @@ class CreateStatement extends Statement
             );
         } elseif ($this->options->has('TABLE')) {
             $this->fields = FieldDefinition::parse($parser, $list);
+            if (empty($this->fields)) {
+                $parser->error(
+                    'At least one field definition was expected.',
+                    $list->tokens[$list->idx]
+                );
+            }
             ++$list->idx;
 
             $this->entityOptions = OptionsArray::parse(
@@ -312,7 +326,7 @@ class CreateStatement extends Statement
                 $token = $list->getNextOfType(Token::TYPE_KEYWORD);
                 if ($token->value !== 'RETURNS') {
                     $parser->error(
-                        '\'RETURNS\' keyword was expected.',
+                        'A \'RETURNS\' keyword was expected.',
                         $token
                     );
                 } else {
diff --git a/libraries/sql-parser/src/UtfString.php b/libraries/sql-parser/src/UtfString.php
index 27e3f93008..1e863a4546 100644
--- a/libraries/sql-parser/src/UtfString.php
+++ b/libraries/sql-parser/src/UtfString.php
@@ -93,7 +93,7 @@ class UtfString implements \ArrayAccess
      */
     public function offsetExists($offset)
     {
-        return $offset < $this->charLen;
+        return ($offset >= 0) && ($offset < $this->charLen);
     }
 
     /**
@@ -190,26 +190,13 @@ class UtfString implements \ArrayAccess
             return 3;
         } elseif ($byte < 248) {
             return 4;
-        } elseif ($byte === 252) {
+        } elseif ($byte < 252) {
             return 5; // unofficial
         }
         return 6; // unofficial
     }
 
     /**
-     * Returns the number of remaining characters.
-     *
-     * @return int
-     */
-    public function remaining()
-    {
-        if ($this->charIdx < $this->charLen) {
-            return $this->charLen - $this->charIdx;
-        }
-        return 0;
-    }
-
-    /**
      * Returns the length in characters of the string.
      *
      * @return int
@@ -220,30 +207,12 @@ class UtfString implements \ArrayAccess
     }
 
     /**
-     * Gets the values of the indexes.
-     *
-     * @param int &$byte Reference to the byte index.
-     * @param int &$char Reference to the character index.
-     *
-     * @return void
-     */
-    public function getIndexes(&$byte, &$char)
-    {
-        $byte = $this->byteIdx;
-        $char = $this->charIdx;
-    }
-
-    /**
-     * Sets the values of the indexes.
+     * Returns the contained string.
      *
-     * @param int $byte The byte index.
-     * @param int $char The character index.
-     *
-     * @return void
+     * @return strin
      */
-    public function setIndexes($byte = 0, $char = 0)
+    public function __toString()
     {
-        $this->byteIdx = $byte;
-        $this->charIdx = $char;
+        return $this->str;
     }
 }
diff --git a/libraries/sql-parser/src/Utils/Misc.php b/libraries/sql-parser/src/Utils/Misc.php
index 9d3dfa99f8..2107172317 100644
--- a/libraries/sql-parser/src/Utils/Misc.php
+++ b/libraries/sql-parser/src/Utils/Misc.php
@@ -8,6 +8,7 @@
  */
 namespace SqlParser\Utils;
 
+use SqlParser\Components\Expression;
 use SqlParser\Statements\SelectStatement;
 
 /**
diff --git a/libraries/sql-parser/src/Utils/Table.php b/libraries/sql-parser/src/Utils/Table.php
index 6b17457d3a..c5ce2fe9db 100644
--- a/libraries/sql-parser/src/Utils/Table.php
+++ b/libraries/sql-parser/src/Utils/Table.php
@@ -125,7 +125,7 @@ class Table
 
                 if (($option = $field->options->has('AS'))) {
                     $ret[$field->name]['generated'] = true;
-                    $ret[$field->name]['expr'] = $option->expr;
+                    $ret[$field->name]['expr'] = $option;
                 }
             }
 
diff --git a/lint.php b/lint.php
new file mode 100644
index 0000000000..b1d4bb414c
--- /dev/null
+++ b/lint.php
@@ -0,0 +1,38 @@
+<?php
+/* vim: set expandtab sw=4 ts=4 sts=4: */
+/**
+ * Represents the interface between the linter and  the query editor.
+ *
+ * @package PhpMyAdmin
+ */
+
+define('PHPMYADMIN', true);
+
+// We load the minimum files required to check if the user is logged in.
+require_once 'libraries/core.lib.php';
+require_once 'libraries/Config.class.php';
+$GLOBALS['PMA_Config'] = new PMA_Config(CONFIG_FILE);
+require_once 'libraries/session.inc.php';
+
+// If user is not logged in, he should not send any requests, so we exit here to
+// avoid external requests.
+if (empty($_SESSION['encryption_key'])) {
+    // Unauthorized access detected.
+    exit;
+}
+
+/**
+ * Loads the SQL lexer and parser, which are used to detect errors.
+ */
+require_once 'libraries/sql-parser/autoload.php';
+
+/**
+ * Loads the linter.
+ */
+require_once 'libraries/Linter.class.php';
+
+// The input of this function does not need to be checked again XSS or MySQL
+// injections because it is never executed, just parsed.
+// The client, which will recieve the JSON response will decode the message and
+// and any HTML fragments that are displayed to the user will be encoded anyway.
+PMA_Linter::lint($_REQUEST['sql_query']);
diff --git a/test/libraries/PMA_Linter_Test.php b/test/libraries/PMA_Linter_Test.php
new file mode 100644
index 0000000000..56667170a5
--- /dev/null
+++ b/test/libraries/PMA_Linter_Test.php
@@ -0,0 +1,147 @@
+<?php
+/* vim: set expandtab sw=4 ts=4 sts=4: */
+/**
+ * Tests for Linter.class.php.
+ *
+ * @package PhpMyAdmin-test
+ */
+
+/*
+ * Include to test.
+ */
+require_once 'libraries/Linter.class.php';
+
+/**
+ * Tests for Linter.class.php.
+ *
+ * @package PhpMyAdmin-test
+ */
+class PMA_Linter_Test extends PHPUnit_Framework_TestCase
+{
+
+    /**
+     * Test for PMA_Linter::getLines
+     *
+     * @return void
+     */
+    public function testGetLines()
+    {
+        $this->assertEquals(array(0), PMA_Linter::getLines(''));
+        $this->assertEquals(array(0, 2), PMA_Linter::getLines("a\nb"));
+        $this->assertEquals(array(0, 4, 7), PMA_Linter::getLines("abc\nde\n"));
+    }
+
+    /**
+     * Test for PMA_Linter::findLineNumberAndColumn
+     *
+     * @return void
+     */
+    public function testFindLineNumberAndColumn()
+    {
+        // Let the analyzed string be:
+        //      ^abc$
+        //      ^de$
+        //      ^$
+        //
+        // Where `^` is the beginning of the line and `$` the end of the line.
+        //
+        // Positions of each character (by line):
+        //      ( a, 0), ( b, 1), ( c, 2), (\n, 3),
+        //      ( d, 4), ( e, 5), (\n, 6),
+        //      (\n, 7).
+        $this->assertEquals(
+            array(1, 0),
+            PMA_Linter::findLineNumberAndColumn(array(0, 4, 7), 4)
+        );
+        $this->assertEquals(
+            array(1, 1),
+            PMA_Linter::findLineNumberAndColumn(array(0, 4, 7), 5)
+        );
+        $this->assertEquals(
+            array(1, 2),
+            PMA_Linter::findLineNumberAndColumn(array(0, 4, 7), 6)
+        );
+        $this->assertEquals(
+            array(2, 0),
+            PMA_Linter::findLineNumberAndColumn(array(0, 4, 7), 7)
+        );
+    }
+
+    /**
+     * Test for PMA_Linter::lint
+     *
+     * @return void
+     */
+    public function testLintEmpty()
+    {
+        $this->expectOutputString('[]');
+        PMA_Linter::lint('');
+    }
+
+    /**
+     * Test for PMA_Linter::lint
+     *
+     * @return void
+     */
+    public function testLintNoErrors()
+    {
+        $this->expectOutputString('[]');
+        PMA_Linter::lint('SELECT * FROM tbl');
+    }
+
+    /**
+     * Test for PMA_Linter::lint
+     *
+     * @return void
+     */
+    public function testLintErrors()
+    {
+        $this->expectOutputString(
+            json_encode(
+                array(
+                    array(
+                        'message' => 'Unrecognized data type. (near <code>IN</code>)',
+                        'fromLine' => 0,
+                        'fromColumn' => 22,
+                        'toLine' => 0,
+                        'toColumn' => 24,
+                        'severity' => 'error',
+                    ),
+                    array(
+                        'message' => 'A closing bracket was expected. (near <code>IN</code>)',
+                        'fromLine' => 0,
+                        'fromColumn' => 22,
+                        'toLine' => 0,
+                        'toColumn' => 24,
+                        'severity' => 'error',
+                    )
+                )
+            )
+        );
+        PMA_Linter::lint('CREATE TABLE tbl ( id IN');
+    }
+
+    /**
+     * Test for PMA_Linter::lint
+     *
+     * @return void
+     */
+    public function testLongQuery()
+    {
+        $this->expectOutputString(
+            json_encode(
+                array(
+                    array(
+                        'message' => 'The linting is disabled for this query because it exceededs the maxmimum length.',
+                        'fromLine' => 0,
+                        'fromColumn' => 0,
+                        'toLine' => 0,
+                        'toColumn' => 0,
+                        'severity' => 'warning',
+                    )
+                )
+            )
+        );
+        PMA_Linter::lint(str_repeat(";", 10001));
+    }
+}