Class: Wee::Examples::Calculator

Inherits:
Component show all
Defined in:
lib/wee/examples/calculator.rb

Overview

NEEDS: FormDecoration

Instance Method Summary collapse

Methods inherited from Component

#add_decoration, #backtrack_state, #backtrack_state_chain, #decoration, #decoration=, #do_render_chain, #each_decoration, #process_callbacks, #process_callbacks_chain, #remove_decoration, #remove_decoration_if

Methods inherited from Presenter

#backtrack_state, #do_render, #get_property, #lookup_property, #process_callbacks, #properties, #properties=, #session, template, uses_property

Constructor Details

#initialize ⇒ Calculator

Returns a new instance of Calculator.



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# File 'lib/wee/examples/calculator.rb', line 4

def initialize
  super()

  @number_stack = []
  @input = "" 
end

Instance Method Details

#append(str) ⇒ Object 



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# File 'lib/wee/examples/calculator.rb', line 54

def append(str)
  @input << str 
end

#clear ⇒ Object 



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# File 'lib/wee/examples/calculator.rb', line 50

def clear
  @input = ""
end

#enter ⇒ Object 



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# File 'lib/wee/examples/calculator.rb', line 45

def enter
  @number_stack << @input.to_f
  @input = "" 
end

#operation(op) ⇒ Object 



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# File 'lib/wee/examples/calculator.rb', line 58

def operation(op)
  unless @input.empty?
    @number_stack << @input.to_f
    @input = ""
  end
  if @number_stack.size < 2
    call Wee::MessageBox.new('Stack underflow!')
  else
    r2, r1 = @number_stack.pop, @number_stack.pop
    @number_stack.push(r1.send(op, r2))
  end
end

#render ⇒ Object 



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# File 'lib/wee/examples/calculator.rb', line 11

def render
  # the number stack

  r.ul { @number_stack.each {|num| r.li(num)} }

  # the display

  r.text_input.value(@input).readonly

  r.space

  r.submit_button.value("Enter").callback(:enter)

  r.submit_button.value("C").callback(:clear)

  r.break

  # the number buttons

  (0..9).each {|num|
    r.submit_button.value(num).callback(:append, num.to_s)
  }

  # the decimal point

  r.submit_button.value(".").disabled(@input.include?(".")).callback(:append, '.')

  # binary operators

  ['+', '-', '*', '/'].each { |op|
    r.submit_button.value(op).callback(:operation, op)
  }
end