Ruby

Overview

My suggestion, learn Python instead. Really. Understanding both languages, that's my professional opinion.

Ruby is a language similar to perl or Python in many regards. It is, in a way, a Lisp-y, Python-y perl.

History

Ruby is unique in that it was first developed and popularized in Japan. I am sure early developers in the US found it fascinating to study a foreign language in a foreign language.

At the time, there wasn't any solid languages to fill the niche that Ruby tries to fill. If Python had been more mature back then, I am sure it would have been adopted.

Ruby on Rails gained in popularity with the PHP refugees. They were leaving PHP because of its numerous bugs and the impossibility of building anything remotely complicated well. Now people are flocking from Ruby on Rails to Node.js, which is sad.

Observations

Having used Ruby extensively for the past few years, as of 2015 these are my practical observations.

• Ruby is really, really hard. No one I know really understands every aspect of the language.
• The syntax of Ruby is very confusing, even for experts. I see a lot of "Spaghetti Noodle Programming": "Run it and see if it works, because heck if I know."
• Ruby doesn't handle exceptions well. It makes writing robust code very difficult.
• Ruby is painfully slow. It seems fast enough in the beginning, but as you start to scale, even moderately, bad things happen.
• Ruby on Rails is a very bad API to program for. Things change so rapidly and so dramatically that you really can't get much help for it. Everyone is always verifying that the version they are talking about is the same before they can answer questions or carry on any kind of conversation.

Recommendation: Avoid at almost every cost.

If your organization already has Ruby on Rails, you don't need to work very hard to replace it with something else. At some point in the lifecycle of the codebase, even the most ardent supporters of Ruby will start looking for something else. Currently (2015) it seems the back-up language is Node.js. I do not understand why people don't switch to Python, or maybe they are and they are quiet about it.

Syntax

Programs

Programs consist of comments and expressions.

Comments

Comments begin with '#' and go to the end of the line. This is just like in Python, perl, and shell.

Ruby also has a POD-like syntax. Lines that begin with '=' mark the beginning of a documentation section, and lines beginning with '=end' end it.

Expressions

Expressions are terminated with semicolons or newlines. A backslash "\" at the end of the line continues the expression on the next line.

String Literals

String literals can be:

• Surrounded by single quotes (')
• Surrounded by double quotes (")
• Started by %, followed by an optional "Q" or "q", then surrounded by any character that is not alphanumeric, even a newline. In the case of brackets, the opening bracket is on the left and the closing is on the right.

In other words, much like perl, except they use %, %q, or %Q instead of q and qq.

Double quoted strings are those with double quotes (") or % or %Q. These interpret the inside a little different than a literal.

Identifiers

Identifiers are much like in C: [a-zA-Z_][a-zA-Z0-9_]*

Reserved Words

The following words may not be identifiers.

BEGIN	 class	  ensure   nil	    self     when
END	 def	  false    not	    super    while
alias	 defined  for	   or	    then     yield
and	 do	  if	   redo     true
begin	 else	  in	   rescue   undef
break	 elsif	  module   retry    unless
case	 end	  next	   return   until

Variables

• Global variables start with '$' and are available everywhere in the program.
• Instance variables start with '@'.
• Constants start with an upper-case letter.
• Special variables are "self", "nil", "true", "false", "__LINE__", and "__FILE__". These have different values depending on where they are executed.
• All other variables are local variables.