title: Slide Show (S9) Code Syntax Highlighting
code-theme: all-hallows-eve


h1. Slide Show (S9) Code Syntax Highlighting

The slideshow (S9) gem now includes the Ultraviolet (Uv) gem that lets you use/turn on
experimental syntax highlighting in your slides for your code. Add @#!ruby@ after
the code block. Example: 

{{{{{{
#!ruby
puts "Syntaxes:"
puts Uv.syntaxes.join( ", " )

puts "Themes:"
puts Uv.themes.join( ", " )
}}}}}} 

Or use any of the other 40+ languages supported by Ultraviolet. Use headers to select any of the 20+ Ultraviolet syntax highlighting themes[1] and/or turn off line numbering. Example:

{{{
code-theme: blackboard
code-line-numbers: false
}}}

fn1. active4d, all-hallows-eve, amy, blackboard, cobalt, dawn, eiffel, espresso-libre, idle, iplastic, lazy, 
mac-classic, pastels-on-dark, slush-poppies, spacecadet, sunburst, twilight, zenburnesque


h1. Rubyize This: 5th Edition

{{{
#!ruby
@wordsToHighlight=["important","monkey","dancing"]
def highlightText(input)
  for i in 0..@wordsToHighlight.length-1 do
    input = input.gsub(@wordsToHighlight[i],"*" + @wordsToHighlight[i] + "*")
  end
  return input
end
}}}

Source: "Rubyize this: 5th edition":http://www.rubyfleebie.com/rubyize-this-5th-edition by RubyFleebie (François Lamontagne)

Refactoring:

{{{
#!ruby
def highlight_text(input, words_to_highlight=%w(important monkey dancing))
  input.gsub(/#{words_to_highlight.join('|')}/i, '*\0*')
end

puts highlight_text("Hey monkey, it's important you start dancing right now!")
# >> Hey *monkey*, it's *important* you start *dancing* right now!
}}}


Another Refactoring:


{{{
#!ruby
class String
  def highlight(words=[])
    words.empty? ? self : self.gsub(Regexp.union(*words), '*\0*')
  end
end

puts "I think it's important to have a dancing monkey in your bedroom.".highlight %w(important monkey dancing)
# => I think it's *important* to have a *dancing* *monkey* in your bedroom.
}}}


h1. Rubyize This: Vancouver RubyCamp 2008 Edition

{{{
#!ruby

# create num random numbers between min and max 
# and print them to a file called file_name, one per line

def create_random_numbers(file_name, min, max, num)
  file = File.open(file_name, 'w')
  n = 0
  while n < num
    r = rand(max - min) + min
    file.puts(r)
    n += 1
  end
  file.close   
end

create_random_numbers('random.txt', 0, 10, 1000)
}}}

Source: "Rubyize this: Live in Vancouver. Refactoring #1":http://spattendesign.com/2008/1/27/rubyize-this-live-in-vancouver 

Refactoring:

{{{
#!ruby
def create_random_numbers(file_name, min, max, num)
  File.open(file_name, 'w') do |file|
    num.times {file.puts(rand(max - min) + min)}
  end
end

create_random_numbers('random.txt', 0, 10, 1000)
}}}

Another Refactoring:

{{{
#!ruby
class Range
  def random_member
    offset = rand(max - min)
    min + offset
  end
end

def create_random_numbers(file_name, range, num)
  File.open(file_name, 'w') do |file|
    num.times { file.puts(range.random_member) }
  end
end

create_random_numbers('random.txt', (0..10), 1000)
}}}


h1. Hello World - From Ada to CSS

Ada

{{{
#!ada
-- Hello World in Ada

with Text_IO;
procedure Hello_World is

begin
  Text_IO.Put_Line("Hello World!");
end Hello_World;
}}}


C

{{{
#!c
/* Hello World in C, Ansi-style */

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
  puts("Hello World!");
  return EXIT_SUCCESS;
}
}}}

CSS

{{{
#!css
/* Hello World in CSS */
body:before {
    content: "Hello World";
}
}}}


h1. Hello World - From Erlang to PHP

Erlang

{{{
#!erlang
%% Hello World in Erlang

-module(hello).

-export([hello/0]).

hello() ->
   io:format("Hello World!~n", []).
}}}

Java

{{{
#!java
// Hello World in Java

class HelloWorld {
  static public void main( String args[] ) {
    System.out.println( "Hello World!" );
  }
}
}}}


PHP

{{{
#!php
<?php
  // Hello World in PHP
  echo 'Hello World!';
?>
}}}