python raw input in haml

py.haml

!!!
%html{:xmlns => "http://www.w3.org/1999/xhtml"}
  %head
    %meta{:content => "text/html; charset=utf-8", "http-equiv" => "Content-Type"}/
    %title raw_input and input 2.6 vs. 3.0
    :css
        %body
    %p input statements
    %p
      using the input() and raw_input() functions
      %br/
      implicitly casting
    %table{:border => "1", :cellpadding => "1", :cellspacing => "1", :width => "864"}
      %tr
        %td{:colspan => "2"}
          %div{:align => "center"}
            %br/
            Version 2.6 and 2.7 (these are the versions we'll be using)
            %br/
            %br/
      %tr
        %td{:width => "347"}
          %pre.style1 var = raw_input( "prompt string" )
        %td{:width => "504"} returns whatever user user typed - up to hitting the ENTER key - as a string
      %tr
        %td
          %pre.style1
            :preserve
              var = input( "prompt string" )
                   # SUGGESTION: DON'T        %td
          returns the numeric value the user types
          %br/
          %em actually
          returns the evaluation as a numeric type of the keystrokes typed
      %tr
        %td{:colspan => "2"}
          %div{:align => "center"}
            %br/
            Version 3.x (this is the "new" version)
            %br/
            %br/
      %tr
        %td
          %pre.style1 var = input( "prompt string" )
        %td returns whatever user user typed - up to hitting the ENTER key - as a string
    %p The prompt string is provided to, well, prompt the (who is almost always an idiot) to type what the programmer wants from them.
    %p
      Whatever the user types is taken up to but not including the ENTER (newline character -
      = succeed ")" do
        %span.style1 '\n'
      and returned.
    %p
      The cursor stays on the same line as the prompt string and there is no blank place after it.
      %br/
      So make sure you are happy with your UI (user interface)
    %p Ugly:(user input shown in bold)
    %p.style1
      \>>> raw_input("Please enter your name")
      %br/
      Please enter your name
      %b test
      %br/
      'test'
      %br/
    %p Pretty:(user input shown in bold)
    %p.style1
      \>>> raw_input("Please enter your name ")
      %br/
      Please enter your name
      %b test
      %br/
      'test'
      %br/
    %p.style2
      Anything the user types is taken - up to but
      %em not including
      ENTER - and returned
    %p.style1
      \>>> raw_input("Go--->>> ")
      %br/
      Go--->>> "this is a test"
      %br/
      '"this is a test"'
    %p.style2 If the user types nothing before ENTER, the NULL STRING is returned.
    %p.style1
      \>>> raw_input("Go--->>> ")
      %br/
      Go--->>>
      %br/
      ''
    %p.style2
      A dumb programmer could decide not to provide a prompt string, which would be a horrible design for their UI.
      %br/
      (And we don't like dumb programmers.)
    %p.style1
      \>>> raw_input()
      %br/
    %p.style3
      [at this point the user stares at the screen, waiting and waiting and waiting for something to happen...]
      %br/
      BAD PROGRAMMER!
    %p
      When you need a numeric input, you'll need to explicitly cast by calling the appropriate function that coerces a string to a numeric type.
      %br/
      %br/
      %span.style1
        \>>> intVal = int(raw_input("enter a small integer value: "))
        %br/
        \>>> floatVal = float(raw_input("enter a floating point value: "))
        %br/
      %span.style1
        \>>> longVal = long(raw_input("enter a integer value (it can be large): "))
        %br/
    %p
      Notice that we used the returned value of the function call to
      %span.style1 raw_input()
      as the parameter to the
      %span.style1 long()
      cast.
    %p SNAKEBYTE:
    %p input vs. raw_input
    %p
      Mostly you will use the raw_input function.
      %br/
      For the
      %span.style1 input
      function, things are a bit different and going to be even worse when you move to 3.0
    %p In python version 2.6/7:
    %p.style1
      \>>> val = input("enter a floating point value: ")
      %br/
      enter a floating point value: 4.3
      %br/
      \>>> val
      %br/
      4.2999999999999998
    %p (Also note the round-off error)
    %p
      %span.style1
        \>>> val = input("type a valid arithmetic expression: " )
        %br/
        type a valid arithmetic expression: 34.6 ** 82
        %br/
        \>>> val
        %br/
        1.6004425935658933e+126
      %br/
    %p
      %strong
        SNAKEBYTE - 2.6/7 vs. 3.x
        %br/
        in Python 3,
        %span.style1 raw_input
        has been
        %em renamed
        to
        %span.style1 input
        and the function previously known as
        %span.style1 input
        has been dropped.
    %p Ouch!
    %p In this course we'll be using 2.6/7.x so hopefully this won't affect anyone.
    %p This means that in 3.x you need to do:
    %p.style1
      amountOwed = float(
      %u>
        %strong input
      ("How much is the bill? ") # 3.x
    %p
      instead of
      %br/
    %p.style1
      amountOwed = float(
      %u>
        %strong raw_input
      ("How much is the bill? ") # will not compile in 3.x
      %br/
      NameError: name 'raw_input' is not defined
      %br/
    %p
      To get the 2.6/7 input way of inputting and evaluating expression strings, you'll have call the eval() function to evaluate an "expression string":
      %br/
    %p.style1
      valueOfExpression = eval(
      %u>
        %strong input
      ("Type a valid arithmetic expression: ") # 3.x
    %p.style1  
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    %p.style1
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    %p  
    %p