From fea051ee9065faf423ddd5c67ef4175cc3e4d87b Mon Sep 17 00:00:00 2001
From: LogMANOriginal <LogMANOriginal@users.noreply.github.com>
Date: Mon, 5 Nov 2018 13:13:15 +0100
Subject: [PATCH] Created Keywords (markdown)

---
 Keywords.md | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 Keywords.md

diff --git a/Keywords.md b/Keywords.md
new file mode 100644
index 0000000..e40e4bd
--- /dev/null
+++ b/Keywords.md
@@ -0,0 +1,23 @@
+`true`, `false` and `null` must be written in lower case letters.
+
+<details><summary>Example</summary><div><br>
+
+**Bad**
+
+```PHP
+if($condition === TRUE && $error === FALSE) {
+    return NULL;
+}
+```
+
+**Good**
+
+```PHP
+if($condition === true && $error === false) {
+    return null;
+}
+```
+
+</div></details><br>
+
+_Reference_: [`Generic.PHP.LowerCaseConstant`](https://github.com/squizlabs/PHP_CodeSniffer/blob/master/src/Standards/Generic/Sniffs/PHP/LowerCaseConstantSniff.php)
\ No newline at end of file