From: Patrick Hurley <phurley@...>
Date: 2007-09-16T08:43:48+09:00
Subject: Re: one line to print the statement AS WELL AS the evaluated value like in C

On 9/15/07, Summercool <Summercoolness@gmail.com> wrote:
> It works!  both for globals and for instance variables...
> but what is this call   dbg{"n"}  using  {  } instead of  (  )
> does it have a name?  and does any book talk about it?
>
> i guess there is no way to do

Using other people's magic try this:

require 'rubygems'
require 'ruby2ruby'

def annotated(&blk)
  # the real magic, thanks ZenSpider :-)
  lines = blk.to_ruby

  # Turn the results into an array
  lines = lines.split(/\n/)

  # Chop off the proc stuff
  lines = lines[1..-2]

  # Find longest expression in block
  max_width = lines.map { |l| l.size }.max

  # scope result, so we can be polite and return it
  result = nil

  # Process each line, why limit ourselves to one
  lines.each do |line|
    # get the result, be sure to keep the correct binding
    result = eval(line, blk.binding)

    # format and display the output line
    puts "#{line} #{" " * (max_width - line.size)}=> #{result.inspect}"
  end

  result
end

array = [1, 2, 3, 4]
annotated do
  array.map { |v| v * 2 }
  array[3] + 1
end

### Needs better exception handling to be "real"
### pth