Trends in Scripting Languages

History For me the purpose of life is partly to have joy. Programmers often feel joy when they can concentrate on the creative side of programming, so Ruby is designed to make programmers happy. Yukihiro “Matz” Matsumoto

History  1993  Fill what lacked in Perl and Python  More powerful than Perl  More Object Oriented than Python  Facilitate creativity  1995 – First release

Basic Syntax #example if-block if goldilocks > 10 puts “too big” elsif goldilocks < 10 puts “too small” else puts “just right” end

Basic Syntax #example function call def my_funct(arg) “Hello #{arg}” end puts my_funct(“world!”)

Example Bear Object Part 1  Initialization  Accessor Methods  Mutator Methods

Types  Seven basic types: numbers strings hashes ranges symbols regular expressions

Types - Numbers num = 81 6.times do puts “#{num.class}: #{num}” num *= num end

Types - Strings  single quoted strings  double quoted strings puts ‘string \n string’ puts “string \n string”

Types - Hashes  Basically Associative Arrays  Uses {} and => notation bears = { “mamma” =>1, “pappa” =>2, “baby” =>3 } puts[“pappa”]

Types - Ranges  Inclusive ranges (‘a’..’e’)  Exclusive ranges (‘a’…’e’)  As a “Comparator” must support comparable operator must implement the succ method

Example Bear Object Part 2  Implementing Range support Comparable operator succ method

Types – Regular Expressions  Pattern matching of String objects  Object of class Regexp declared from constructor defined directly re1 = Regexp.new(‘[a-z]’) re2 = /[a-z]/ “Goldilocks” =~ re1 “GOLDILOCKS” =~ re1

Scope of Variables  Specific syntax for declaring scope LocalGlobalInstanceClassConstant  Local  within each block  Global, Instance, Class  maintain their scope with their respective definition Can use the :: operator i.e. ClassName::ConstName

Conclusion  A programmer’s language  Readability vs. Writability  Facilitate creativity?

Questions?