GNU M4 - GNU M4 is an implementation of the m4 macro preprocessor.
Python - Python is a clear and powerful object-oriented programming language, comparable to Perl, Ruby, Scheme, or Java.
GCC C Preprocessor (cpp) - Top (The C Preprocessor)
Java - A concurrent, class-based, object-oriented, language specifically designed to have as few implementation dependencies as possible
PP - A generic Preprocessor - P is a text preprocessor designed for Pandoc (and more generally Markdown and reStructuredText).
Rust - A safe, concurrent, practical language