Class: Nudge::Stack

Inherits:
Object
  • Object
show all
Defined in:
lib/interpreter/stack.rb

Overview

Nudge Stacks are Arrays with some added convenience functions.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ Stack

Stack name must be a symbol

Raises:

  • (ArgumentError) 


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# File 'lib/interpreter/stack.rb', line 12

def initialize(name)
  raise(ArgumentError,"Stack name must be a Symbol") if !name.kind_of?(Symbol)
  @name = name
  @entries = []
end

Instance Attribute Details

#entries ⇒ Object

Returns the value of attribute entries.



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# File 'lib/interpreter/stack.rb', line 8

def entries
  @entries
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/interpreter/stack.rb', line 9

def name
  @name
end

Instance Method Details

#depth ⇒ Object

Stack#depth returns the number of items



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# File 'lib/interpreter/stack.rb', line 34

def depth
  @entries.length
end

#inspect ⇒ Object 



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# File 'lib/interpreter/stack.rb', line 38

def inspect
  result = @entries.reverse.inject("[") do |return_string, item|
    return_string << "\n«#{item.type}» #{item.value},"
  end
  result.chop+"]"
end

#peek ⇒ Object

Reference to the last item pushed to the Stack. Doesn’t remove it



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# File 'lib/interpreter/stack.rb', line 29

def peek
  return @entries.last
end

#pop ⇒ Object

Removes the last item pushed to the Stack and returns it



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# File 'lib/interpreter/stack.rb', line 24

def pop
  return @entries.pop
end

#push(item) ⇒ Object

Only non-nil objects can be pushed; there is no type checking or validation beyond that.



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# File 'lib/interpreter/stack.rb', line 19

def push(item)
  @entries.push(item) unless item == nil
end