Class: RVM::Languages::Math::Tree

Inherits:
Object
  • Object
show all
Defined in:
lib/rvm/languages/math/tree.rb

Constant Summary collapse

PRIORITIES = 
{
  ';' => -100,
  '=' => -50,
  '(' => 0,
  '+' => 10,
  '-' => 10,
  '*' => 20,
  '/' => 20,
  '^' => 30,
}
ASSOSICATIONS = 
{
  ';' => :right, 
  '+' => :left,
  '-' => :left,
  '*' => :left,
  '/' => :left,
  '^' => :right,
  '=' => :right
}

Class Method Summary collapse

Class Method Details

.generate(tokens) ⇒ Object 



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# File 'lib/rvm/languages/math/tree.rb', line 24

def Tree.generate tokens
  output = []
  dbgoutput = []
  stack = []
  dbgstack = []
  while not tokens.empty?
    token = tokens.shift
    case token[1]
      when :function 
      fun = token[0]
      stack << {:type => :function, :op => fun}
      output << {:type => :function_end}
      dbgoutput << ')'
      dbgstack << fun
      when :function_sep
      while stack.last && (stack.last[:type] != :function)
        output << stack.pop
        dbgoutput << dbgstack.pop
      end
      when :paren_open
      op = token[0]
      stack << {:type => :op, :op => op}
      dbgstack << op
      when :paren_close
      while stack.last && (stack.last[:op] != '(')
        output << stack.pop
        dbgoutput << dbgstack.pop
      end
      stack.pop
      dbgstack.pop
      when :number
      output << {:type => :number, :number => token[0]}
      dbgoutput << token[0]
      when :ident
      output << {:type => :ident, :ident => token[0]}
      dbgoutput << token[0]
      when :opperator
      op = token[0]
      ass = ASSOSICATIONS[op]
      o1p = PRIORITIES[op]
      while stack.last && (stack.last[:type] != :function) &&
       (((ass == :left) && (o1p <= PRIORITIES[stack.last[:op]])) || 
       ((ass == :right) && (o1p < PRIORITIES[stack.last[:op]])))
        output << stack.pop
        dbgoutput << dbgstack.pop
      end
      stack << {:type => :op, :op => op}
      dbgstack << op
    else
       raise "Unknown element in parser tree: #{token.inspect}"
    end
    p(dbgstack) if $DEBUG
    p(dbgoutput) if $DEBUG
  end
  while not stack.empty?
    output <<  stack.pop
  end
  gen_tree output
end