Update README.md

Author: josef-poetzl

README.md

@@ -1,2 +1,29 @@
 # ACLibDeclarationDictionaryCore
 This Add-In lists all VBA declarations (variables, function names, constants, etc.) and ensures consistent letter case - Core components
+
+## API
+
+### RunVcsCheck([OpenDialogToFixLettercase], [DeclDictFilePath]) As Variant
+Compare lettercase from CurrentVbProject with saved (table/file) dictionary items
+ 
+#### Parameters
+- OpenDialogToFixLettercase - (Boolean) - Open dialog to fix lettercase
+- DeclDictFilePath - (String) - use alternative file path
+
+#### Returns
+- Boolean (True) ... if DiffCount = 0
+- String ... if DiffCount > 0 => "Failed: <lettercase info>"
+ 
+#### Example
+```
+Dim Result As Variant
+Result = Application.Run(Environ("appdata") & "\Microsoft\AddIns\ACLibDeclarationDictCore.RunVcsCheck", True)
+If Result = True Then
+    Debug.Print "No problems with letter case"
+Else
+    Debug.Print Result
+End If
+```
+
+### RunVcsCheckDialog()
+Equal to RunVcsCheck(True)