Ruby - Scripting and web services

Ruby has been designed by Yukihiro "Matz" Matsumoto from 1993 to 1995. The goal was to program in human style rather than adapting its mind to the computer structure. This was firmed up by applying a principle of least surprise that means that the language syntax is always as the programmer does expect it is. But there is also a lot of conventional rules to simplify the programming: only a way to do a thing.
It is interpreted (uses bytecode), fully object-oriented and dynamically typed. Has been inspired by Perl, Smalltalk and Python.
Ruby on rails was released in 2004. This is an alternative to Ajax, easier and more complete but requires the server-side part to be (re)written in Ruby also.

Features

• By the trickery of the "main" object, variables and functions becomes attributes and methods.
• Single inheritance.
• Operator overloading.
• Closures and continuations.
• Threads, exceptions.
• Reflection.
• UTF-8.

The language

Syntax

Capitalized or uppercase identifiers are constants.
Floating point numbers are denoted by a dot followed by a number or zéro.
Variables:
- global variables start with $
- attributes in classes start with @
- local variables are simple identifiers.

Symbols

# starts a comment.
[ exp, ... ] enclose arrays.
{ 1 => a, ... } is for a dictionary.

Control structures

The if structure has elsif and else options.

 if x < 10 then
   print "x less than 10\n"
 else
   print "etc...\n"
 end

 while expr [do]
    ... 
 end 
         

Function or method

The definition starts with the def keyword, plus the name and the list or arguments separated by commas, then the statements and is terminated by the end keyword.
The return keyword in the body of the definition allows to return one or several values.

def funcname( arguments )
 ...statements...
 return x, y, z
end

Class

  class name
    ...
  end

Why to use Ruby?

The language was locally used before the rails framework appears and shares its success with the language itself.

Sites

• Main
  The interpreter may be downloaded on the main site.
• Dmoz
  Ruby in the open directory.
• Ruby-doc
  Documentation for Ruby only.
• Ruby On Rails
  Main site for the successful framework.

Sample code

do puts "Hello, World!" end  

mylist = [ "d", "e", "m", "o" ] 
 
for i in mylist do
  print i, "\n"
end 

References

The Ruby reference manual.