Update 'Coding Style'

Coding-Style.md

@@ -282,6 +282,28 @@ Do eliminate trailing whitespace on any line, preferably as a separate patch or
 
 ### Conditions
 
+Boolean values should not be checked for equality to make the code more readable:
+```c
+if (error)
+  return 1;
+
+if (!error)
+  return 0;
+```
+
+The check for 0 should refer to the specific way the 0 is used: `0` for a numeric value, `'\0'` for the end of a string, or `NULL` for a pointer. In this way, the variable type can be derived implicitly by reading the comparison. For the FALSE boolean we refer to the rule about boolean equations.
+```c
+if (buffer == NULL)
+    return NULL;
+
+if (get_bit (stream) == 0)
+    node->value++;
+
+if (bwc->info.file_ext [0] != '\0')
+    return 0;
+```
+
+
 ### Functions
 The following general rules should be followed when defining a function in BigWhoop:
 * Function name must be lowercase, optionally separated with underscore _ character