Awesome

Program.java.rb.ws.txt

Program.java.rb.ws.txt is a “simple” piece of esoteric script. Even though it looks like a mess when viewed as plaintext, it is, in fact, valid for not one, not two, but three programming languages:

• When compiled by Java (Program.java), it will print ‘Java’;
• When interpreted with Ruby (Program.java.rb), it will print ‘Ruby’; and
• I even squeezed the easy-to-interlace (but no-so-easy-to-actually-write) language Whitespace (Program.java.rb.ws) into the mix. Yup, it will print ‘Whitespace’.

How the heck did I mix three programs together

The esoteric programming language Whitespace only reads Spaces ( ), Tabs (\t) and Line-Feeds (\n). Non-whitespace characters are ignored and therefore can even code for another programming language. This inspired me to see if two practical languages can be mixed into a single file.

I am familiar with Ruby and Java, and conveniently, ‘//’ begins a single-line comment but makes an empty RegExp in Ruby. With it, Java ignores the first line of the script and reads after it, whereäs Ruby takes it as a function whose parameter is the lengthy Java code and whose computed value unused. Because Java does not bother with whitespaces, splitting its code among multiple lines is the cherry I placed on the top.

To include the Ruby script, the Java side wraps it inside a multi-line comment (/* … */). The Ruby side then close the String parameter, do its job, and closes Java’s comment with its own single-line comment. Finally, the Whitespace script was inserted back in as a “cheap” freebie.