For the DSL I have developed, I wanted to have Geany support it as it does the embedded languages like java and C#. I created filetypes.myLang.conf and added the configuration fields as in the manual. For the filed [settings] I added : lexer_filetype=C Now everything seems fine. My language comes in the list in Geany and the syntax is highlighted based on the keywords defined in primary and secondary fields in the config file. My question is, should I add a lexer file for my language or setting it as I've done is ok. If the answer is yes, could someone explain to me how this is done. Also, what's the meaning of this field?