SimpleEdit

These definitions can be easily created and edited with SimpleEdit itself or you can use any other Plist Editor. The definitions are stored in a sub folder of its 'Application Support Folder'.

This can be found in the Mac App Store version here:
~/Library/Containers/com.myownapp.SimpleEdit/Data/Library/Application\Support/SimpleEdit/Definitions

And in the Non-MAS version here:
~/Library/Application\Support/SimpleEdit/Definitions

These definitions are 'loaded' every time you start SimpleEdit or when you create a new document. A definition is nothing else than a dictionary with objects and keys - much like JSON. You can think of definitions as rules for a language. They describe how your code's syntax will be highlighted and how you comment it. They also contain the words that are used for the completion. You will also find the items used for the command menu in such a definition file.

Currently SimpleEdit comes with the following definitions:

CSS
HTML
Java
JavaScript
LaTeX
Objective-C
Swift
PHP
Plist
Text
XML

You can create as many definitions as you like and usually you directly select one when you create a new document - but, of course, you can change them at any time.

There is a reason why, at the moment, only these languages have a definition file - I don't know anything about other languages. It would be AWESOME if you could send me your definitions so that I can offer them for downloading here.

SimpleEdit is capable of working with any language, the syntax highlighting is designed to do more than just highlight some keywords. The customizable command menu can handle simple snippets, insert and replace strings, handle templates, open links, run terminal commands** - you can communicate with other Apps via AppleScript** and you can even send URL request. Please keep in mind that the sandboxed App Store version has limitations I can do nothing about and that, of course, not every fancy long-winded command may be possible simply because I have to support a wide range of possibilities.

Of course, you have to know what you are doing before you start to write furious emails - which you can do here by the way. Please check for your self first, that the problem does not sit in front of your screen. Chances are that I'm the culprit and I will happely fix it.

You may want to use this definition file as a starting point. I've used a similar approach that you may already know from other editors.

A definition needs a title and you can make it your default definition. For different tasks you could create different definitions - even if it is the same language.