php/php-langspec — pull request #69 by smalyshev (2014-08-27 09:02:02+00:00)
Title: Lexical structure fixes

The following major changes were made:
- Null & boolean literals removed since those are not literals but constants
- Added variable substitution part with detailed description & syntax
- Changed negative literals description to be less conversational and more normative
- Changed references to c-constant to a constant expression