Q:

Custom Syntax Highlighting in Sublime Text 3 – cannot convert

I am trying to create my own syntax highlighting for Sublime Text 3. The main purpose of it is to distinguish text written in Latin script from text written in Cyrillic script. I have already installed AAAPackageControl and read the tutorial, but I cannot make it work for some reason.
Here's the syntax I wrote
# [PackageDev] target_format: plist, ext: tmLanguage
---
name: ADVANCED TEXT
scopeName: text.mirkowy
fileTypes: []
uuid: 78dbe755-58eb-4cdf-b954-4438334aedb9

patterns:
- comment: Words in Latin Script
  name: latin_text.text.mirkowy
  match: [A-Za-z]+
- comment: Words in Cyrillic Script
  name: cyrillic_text.text.mirkowy
  match: [ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюяёђѓєѕіїјљњћќўџҐґ]+
- comment: Numbers
  name: numbers.text.mirkowy
  match: \d
...

However, when I press F7 to convert that file to plist, I keep getting and error and I don't understand why (bear in mind that I am completely new to creating one's own syntaxes and the like) — here's what it looks like:
Input type not specified, auto-detecting... YAML
No target format specified, searching in file... Property List
Parsing YAML... (C:\Users\iyoossaev\AppData\Roaming\Sublime Text 3\Packages\User\mirkowy.YAML-tmLanguage)
Error parsing YAML: while parsing a block mapping

What do I do wrong?

A:

You almost got it, but there is a minor issue with your regexes - character classes surrounded by square brackets [ ] need to be within parentheses ( ). Your "Numbers" regex \d works fine without parens. So, just change your code to the following:
# [PackageDev] target_format: plist, ext: tmLanguage
---
name: ADVANCED TEXT
scopeName: text.mirkowy
fileTypes: []
uuid: 78dbe755-58eb-4cdf-b954-4438334aedb9

patterns:
- comment: Words in Latin Script
  name: latin_text.text.mirkowy
  match: ([A-Za-z]+)

- comment: Words in Cyrillic Script
  name: cyrillic_text.text.mirkowy
  match: ([ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюяёђѓєѕіїјљњћќўџҐґ]+)

- comment: Numbers
  name: numbers.text.mirkowy
  match: \d

and you should be all set. Note that I put a blank space between each block - it's not required, but it helps you visually separate each block, which comes in very useful when you get very complicated blocks.
If you'd like some examples of more complex .YAML-tmLanguage syntax definitions, two places come immediately to mind. The first is the Syntax Definitions folder in the PackageDev package itself. The second is actually in a personal project of mine, the Python Improved syntax definition which aims to be a much better replacement for the built-in Python syntax that ships with Sublime. You can find the source for PythonImproved.YAML-tmLanguage on Github. Feel free to open an issue there if you have any questions on syntax design, or just ask a new question here. 
Good luck!

